[top]
000
FXUS64 KLIX 212122
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
322 PM CST SAT NOV 21 2009
.SHORT TERM...
SURFACE LOW PRESSURE SYSTEM ESTIMATED 1006MB ABOUT 40 MILES SOUTH
OF MARSH ISLAND AND MOVING NORTHEAST AROUND 15 KNOTS TOWARDS
POINTE AU FER ISLAND. IT SHOULD MOVE ASHORE AROUND 7 PM AND PLACE
THE LOWER PARISHES BRIEFLY IN WARM SECTOR FOR A SHORT DURATION
OPPORTUNITY OF SURFACE BASED CONVECTION. TORNADIC SUPERCELL
INDICATED IN THE COASTAL WATERS ABGOUT 15 MILES SOUTH OF MS RIVER
DELTA IS MOVING RIGHT OF MEAN FLOW AND TRAJECTORY SHOULD KEEP CELL
WELL AWAY FROM LAND AREAS...BUT PROMPTED MARINE WARNINGS FOR
LIKELY TORNADIC WATERSPOUT. OTHER WEAKER ROTATING CELL MOVED
ASHORE NEAR CAMINADA PASS AND WEAKENED. DRY SLOT HAS WORKED AROUND
OCCLUDED LOW CIRCULATION AND APPEARS TO BE DESTABILIZING THE
AIRMASS NEAR THE COAST. WILL CONTINUE TO BE VIGILANT FOR DEEPER
CONVECTIVE DEVELOPMENT...BUT MANY FACTORS INHIBITING CONDITIONS TO
BE ANY MORE THAN AN ISOLATED RISK AT BEST THROUGH THE EVENING.
MODELS SEEM TO HAVE BETTER HANDLE ON SITUATION THAN PAST RUNS AND
WILL BE GOING CLOSE TO GFS WITH REGARDS TO SYSTEM PASSAGE AND WIND
FIELDS...THEREBY DICTATING REST OF FORECAST ELEMENTS. WRAP-AROUND
CLOUDS MAY REMAIN IN THE AREA SUNDAY UNTIL DEFORMATION ZONE AND
UPPER TROUGH FINALLY MOVES EAST OF REGION AND SOME LIGHT SPRINKLES
OR PATCHES OF DRIZZLE MAY TAKE PLACE AT TIMES SUNDAY
MORNING...WILL NOT ANTICIPATE ANY MEASURABLE AMOUNTS AFTER SUNRISE
SUNDAY.
.LONG TERM...
LOWER EXTENSION OF COLD FRONT SWINGS THROUGH THE REGION TUESDAY
BUT MODELS CONTINUE TO INDICATE LOW LEVEL MOISTURE DIVERGING UPON
ARRIVAL. NO CHANGES MADE TO THE LONG TERM AS DRY DAYS ARE EXPECTED
THROUGH THE WEEK. TEMPERATURES SHOULD BE NEAR TO SLIGHTLY BELOW
NORMAL EACH DAY.
&&
.AVIATION...
SCATTERED SHOWERS CONTINUE TO MOVE ACROSS THE AREA. DRY AIR HAS BE
PROTRUDING IN FROM THE SOUTH...WITH RAIN TO IN ALL DIRECTIONS AROUND
TERMINALS BUT SOUTH. A LARGE BAND OF LIGHT TO MODERATE RAIN TO THE
WEST OF THE AREA WILL TRACK EASTWARD ACROSS THE AREA THIS EVENING.
CIGS AND VIS WILL LOWER TO IFR WITH THIS RAINFALL. ACTIVITY SHOULD
DIMINISH THROUGH THE OVERNIGHT HOURS. IFR CIGS WILL MOVE IN FROM THE
WEST TONIGHT AS LOW PRESSURE SYSTEM JUST OFF THE LA COAST MOVES ENE
ACROSS THE COASTAL PARISHES. VIS SHOULD BE MVFR OR LOWER THROUGH THE
NIGHT DUE TO SATURATED SOIL. CONDITIONS WILL BE SLOW TO IMPROVE
TOMORROW. MEFFER
&&
.MARINE...
WILL MAINTAIN SMALL CRAFT ADVISORY THROUGH 6 PM AS WINDS APPEAR TO
BE INCREASING INTO CRITERIA WITH THE APPROACH OF THE LOW. WINDS
SHOULD DIMINISH RATHER QUICKLY AFTER LOW MOVES ASHORE EARLY THIS
EVENING. GUSTINESS MAY CONTINUE THROUGH SUNDAY AS DRIER AIR AND
MODEST COLD AIR ADVECTION MOVES INTO THE NORTH GULF.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 49 60 48 69 / 80 10 10 0
BTR 51 62 48 69 / 40 10 10 0
MSY 54 63 51 69 / 70 10 10 0
GPT 55 65 50 69 / 80 20 10 0
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM SATURDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER TO LOWER ATCHAFALAYA RIVER LA FROM 20 TO
60 NM...AND COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER TO LOWER ATCHAFALAYA RIVER LA OUT 20 NM.
MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM SATURDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER TO LOWER ATCHAFALAYA RIVER LA FROM 20 TO
60 NM...AND COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER TO LOWER ATCHAFALAYA RIVER LA OUT 20 NM.
&&
$$
24/RR
MEFFER
[top]
000
FXUS64 KSHV 212107
AFDSHV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
307 PM CST SAT NOV 21 2009
.DISCUSSION...
LARGE SLOW MOVING UPPER LEVEL LOW PRESSURE SYSTEM OVER THE
LOUISIANA GULF COAST WILL CONTINUE TO DRIFT SLOWLY EAST TO THE
ALABAMA AREA BY SUNDAY AFTERNOON. RAINFALL WILL CONTINUE INTO THE
EVENING OVER THE CENTRAL LOUISIANA ZONES...INCLUDING THE NORTH
CENTRAL LOUISIANA AREA NEAR MONROE...AS MOISTURE WRAPS AROUND THE
LOW PRESSURE SYSTEM UP INTO LOUISIANA. LATE TONIGHT RAIN SHOULD
GRADUALLY TAPER OFF FROM WEST TO EAST...AS THE WHOLE SYSTEM MOVES
EAST.
THE PERIOD OF SUNDAY AND MONDAY LOOK TO BE DRY IN BETWEEN
SYSTEMS. THE NEXT POSSIBLE RAIN MAKER WILL BE A COLD FRONT THAT
WILL MOVE THROUGH THE FOUR STATE AREA MONDAY NIGHT AND TUESDAY.
THIS PROBABLY WONT BE AS EFFICIENT A RAIN MAKER AS THIS PAST UPPER
LOW SYSTEM THAT MOVED ALONG THE GULF COAST. THE FRONT WONT HAVE AS
MUCH MOISTURE TO WORK WITH MONDAY NIGHT AND TUESDAY...BUT IT WILL
PROBABLY PRODUCE A NARROW LINE OF SHOWERS AND THUNDERSTORMS
SOMETIME LATE MONDAY NIGHT AND/OR TUESDAY MORNING AS THE FRONT
MOVES THROUGH THE AREA.
LATE NEXT WEEK LOOKS TO BE DRY ALTHOUGH A FAIRLY STRONG
REINFORCING COLD FRONT WILL MOVE THROUGH THE FOUR STATE AREA
AROUND WEDNESDAY NIGHT. LOOKS TO BE RATHER CHILLY FOR THANKSGIVING
AND THE END OF NEXT WEEK.
&&
.AVIATION...
SURFACE LOW OUT OVER THE GULF IS OFFSHORE SOUTH OF KLFT AND SLOWLY
MOVING EASTWARD. THE UPPER LOW IS OVER KLCH. MOISTURE WRAPPING
AROUND THE LOW IS MOSTLY IN THE MID LEVELS OVER OUR CWA WITH VFR
CONTINUING FOR ALL BUT KLFK WHERE MVFR IS LINGERING. CIGS ARE
DROPPING A BIT IN THE WAKE OF THE LOW...BUT WILL KEEP VFR THIS
PM...BUT CANT RULE OUT IFR/MVFR FOR A COUPLE OR FEW TERMINALS
OVERNIGHT. SFC WINDS ARE LIGHT N/NE FOR OUR TERMINALS AND WILL
KEEP LESS THAN 10 KTS FOR THIS TAF CYCLE. LOOK FOR THE RAIN CLOUDS
TO EXIT EASTERN SECTIONS THIS EVENING AS THE LOW MOVES OUT...BUT
IFR CIGS/VSBY MAY DEVELOP GENERALLY ALONG AND SOUTH OF I-20
OVERNIGHT AND FOR EARLY DAYLIGHT ON SUNDAY AS THE WINDS SLACK.
IMPROVEMENTS BY LUNCH AS WEAK 1017 MB HIGH PRESSURE BUILDS IN OVER
TEXAS.
/24/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 48 65 45 71 52 / 30 0 0 10 20
MLU 49 63 44 69 48 / 60 10 0 10 20
DEQ 44 66 43 69 47 / 20 0 0 10 30
TXK 48 65 44 69 50 / 20 0 0 10 30
ELD 47 63 42 69 50 / 40 0 0 10 20
TYR 46 67 47 72 52 / 10 0 0 10 20
GGG 46 67 45 73 50 / 10 0 0 10 20
LFK 48 68 45 74 52 / 30 0 0 10 20
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
03/24
[top]
000
FXUS64 KLCH 212047
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
247 PM CST SAT NOV 21 2009
.DISCUSSION...SURFACE ANALYSIS NOW INDICATING SURFACE LOW JUST
OFFSHORE NEAR MARSH ISLAND. RADAR SHOWING BULK OF RAINS NORTH OF
INTERSTATE 10...NORTH AND NORTHEAST OF FEATURE.
SURFACE LOW...MID LEVEL LOW AND UPPER TROF TO ADVANCE EAST NORTHEAST
OVERNIGHT WITH ANY LINGERING RAINS COMING TO AN END. REMAINDER OF
THE WEEKEND LOOKING PLEASANT WITH DRIER AIR ADVECTING IN FROM A LOW LEVEL
NORTHERLY FLOW...TRENDING TOWARD ZONAL ALOFT. EXPECTING SEASONABLY
WARM DAYS AND COOL NIGHTS BOTH SUNDAY AND MONDAY.
NEXT RAIN CHANCE ARRIVES TUESDAY WITH OUR NEXT FRONTAL PASSAGE
DEPICTED SIMILARLY BY THE GFS AND ECMWF. COOLER 1025 MB HIGH
FOLLOWING FROPA WILL BRING LOWER TEMPS THROUGH THE REMAINDER OF
THE WEEK ALONG WITH AN EXTENDED DRY PERIOD.
&&
.MARINE...WINDS WILL WEAKEN OVERNIGHT AND SEAS LOWER AS LOW
PRESSURE MOVES INLAND OVER SOUTH CENTRAL LOUISIANA THEN ADVANCES
EAST NORTHEAST. AN OFFSHORE FLOW WILL CONTINUE THROUGH THE
REMAINDER OF THE WEEKEND...BECOMING SOUTHERLY MONDAY AHEAD OF OUR
NEXT FRONTAL PASSAGE EXPECTED TUESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 49 67 46 72 53 / 20 0 0 0 10
KBPT 49 68 47 74 56 / 10 0 0 0 20
KAEX 48 65 43 70 47 / 50 10 0 0 10
KLFT 50 64 48 70 51 / 30 10 0 0 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE
FOLLOWING ZONES: CALCASIEU LAKE...COASTAL WATERS FROM
CAMERON, LA TO HIGH ISLAND, TX OUT 20 NM...COASTAL WATERS
FROM INTRACOASTAL CITY TO CAMERON, LA OUT 20 NM...COASTAL
WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY,
LA OUT 20 NM...SABINE LAKE...VERMILION BAY...WATERS FROM
CAMERON, LA TO HIGH ISLAND, TX EXTENDING FROM 20 NM TO 60
NM...WATERS FROM INTRACOASTAL CITY, LA TO CAMERON, LA
EXTENDING FROM 20 NM TO 60 NM...WATERS FROM LOWER
ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA EXTENDING FROM
20 NM TO 60 NM.
&&
$$
000
FXUS64 KLIX 211755
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1155 AM CST SAT NOV 21 2009
.AVIATION...
WIDESPREAD SHOWERS CONTINUE TO MOVE ACROSS THE AREA. GPT IS THE
ONLY SITE NOT SEEING RAIN...BUT SHOULDN/T BE TOO MUCH LONGER. IFR
CIGS HAVE BEEN FAIRLY SPORADIC BUT SHOULD BECOME MORE COMMON LATER
TONIGHT. SO...EXPECT OFF AND ON LIGHT TO OCCASIONALLY MODERATE
SHOWER THROUGH 00Z AND TAPERING OFF AFTER THAT. IFR CIGS AND MVFR
VIS WILL RESUME THROUGH MUCH OF THE REST OF THE PERIOD.
&&
.PREV DISCUSSION... /ISSUED 738 AM CST SAT NOV 21 2009/
UPDATE...
SOUNDING DISCUSSION...
THE ATMOSPHERE HAS BECOME SATURATED FROM 815 MB TO 580
MB...PRECIPITABLE WATER VALUE IS 1.10 INCHES. AN ALTOSTRATUS CLOUD
DECK WAS PRESENT AT LAUNCH DUE TO QUITE A BIT OF STRATIFORM RAIN
MOVING ACROSS THE CWA ALONG WITH A FEW EMBEDDED STRONGER SHOWERS.
AN INVERSION IS PRESENT NEAR 3000 FEET WHILE WINDS ARE OUT OF THE
EAST AT THE SURFACE SHIFTING SOUTH THEN SOUTHWEST ALOFT.
PREV DISCUSSION... /ISSUED 403 AM CST SAT NOV 21 2009/
SHORT TERM...AT 9Z THE SFC LOW WAS LOCATED JUST EAST OF THE CNTRL
TX COAST AND STILL WELL SW OF THE CWA WHILE A LARGE AREA OF SHRA ARE
MAKING THERE WAY NORTH ONTO THE SWRN AND S-CNTRL LA COAST. THERE IS
AN AREA OF TSRA WELL SOUTH OF THE LA COAST AND THESE WERE MAINLY
MOVING TO THE EAST. THE MID LVL DISTURBANCE WAS STILL BACK IN ERN TX
TODAY THROUGH TOMORROW...THERE IS STILL SOME UNCERTAINTY IN THE
TRACK OF THE SFC LOW. EVEN THOUGH THE MDLS ARE WITHIN THE NOISE LVL
THE GFS IS FURTHER SOUTH THAN THE ECMWF. LOOKING AT CURRENT
FEATURES...MSAS SHOWS BEST PRESSURE FALLS EAST TO ENE OF THE SFC LOW
ALONG WITH THE STRONGEST CONVECTION WELL INTO THE GULF MOVING EAST.
THE GFES AND SREF ARE ALSO MORE IN LINE WITH THE GFS AND WITH ALL OF
THIS I PREFER THE FURTHER SOUTH TRACK. THAT SAID ANY DEVIATION
NORTH(EVEN BY JUST 50 MILES) WOULD MAKE A PRETTY GOOD DIFFERENCE IN
STRONG/SVR RISK. WITH THE TRACK EXPECTED TO REMAIN JUST OFF THE
COAST TODAY THE WARM SECTOR WILL REMAIN OVER THE COASTAL WATERS
MAKING TODAY MORE OF A ISENTROPIC LIFT/WAA SHRA DAY AND THIS SHOWS
UP REALLY WELL IN THE 290-300K LVLS FOR OUR CWA. WITH THAT SAID I
EXPECT THE LARGE AREA OF SHRA JUST OFF TO OUR SW TO CONTINUE TO
EXPAND TO THE NE THROUGH THE MORNING. THERE WILL EVEN BE ISLTD TO
SCT TSRA EMBEDDED IN THIS ACTIVITY THANKS TO ELEVATED
INSTABILITY(SHOWALTERS NEAR -3). AS FOR RAINFALL TOTALS AREA WIDE
1-2" LOOK PRETTY GOOD. THE HEAVIEST RAIN WILL LIKELY OCCUR ALONG AND
SOUTH OF A LINE FROM MORGAN CITY TO LUCEDALE THIS AFTN. THIS
LOCATION LINES UP WELL WITH THE LFQ OF A 100KT SUBTROPICAL JET.
OUR SFC LOW WILL CONTINUE TO PUSH ENE ALONG/JUST OFF THE COAST AND
SHOULD BE ALONG THE AL COAST BY TOMORROW MORNING. THIS WILL LEAD TO
VERY GOOD RAIN CHANCES ACROSS THE ERN HALF OF THE CWA THIS EVN WITH
RAIN TAPERING OFF AFTER MIDNIGHT. ACROSS THE SW WE COULD SEE RAIN
COME TO AN END QUICKLY LATE THIS AFTN/EARLY EVN AS WE SHOULD BEGIN
TO GET DRY SLOTTED. BY TOMORROW MORNING LIGHT RAIN MAY STILL BE
OCCURRING ACROSS THE EXTREME ERN PORTIONS OF THE CWA AND POSSIBLY IN
OUR OUTER WATERS. SUNDAY MAY BE A DREARY COOL DAY AS THE MID LVL
DISTURBANCE WILL BE SLOW TO LIFT OUT OF THE LOWER MS VALLEY TWRDS THE
TN VALLEY. THE LL THERMAL TROUGH WILL REMAIN WEST OF THE AREA SO WE
EXPECT TO SEE A GOOD BIT OF LOW CLOUDS STILL. /CAB/
LONG TERM...NO BIG CHANGES IN THE EXTENDED. THERE AREA SOME TIMING
DIFFERENCES B/T THE MEDIUM RANGE MDLS WITH THE PASSAGE OF THE NEXT
FRONTAL SYSTEM BUT OVERALL THE MDLS ARE IN GENERAL AGREEMENT AND
YOUR TURKEY DAY IS LOOKING RATHER QUIET ALONG THE N-CNTRL GULF COAST
AND LOWER MS VALLEY. WITH MAINLY JUST TIMING ISSUES I WILL USE A
BLEND OF THE GFS AND ECMWF WITH OUR NEXT SYSTEM
THE FIRST HALF OF THE WORK WEEK WILL BEGIN QUIET BUT ANOTHER MOSTLY
DRY FRONTAL SYSTEM WILL APPROACH THE AREA SOMETIME TUE/TUE NIGHT/WED
MORNING. BY MON NIGHT ANOTHER DISTURBANCE WILL DROP INTO THE
CNTRL/NRN PLAINS WITH A SFC LOW DEEPENING JUST WEST OF THE MID/UPPER
MS VALLEY. AS THIS SYSTEM PUSHES EAST TUE IT WILL DRAG A COLD FRONT
ACROSS THE SRN PLAINS AND INTO THE LOWER MS VALLEY. AGAIN THERE IS
SOME UNCERTAINTY AS TO WHEN THE FRONT WILL PUSH INTO THE CWA BUT IT
IS LOOKING LIKE SOMETIME TUE AFTN/EVN. NOW MOISTURE RETURN WILL BE
QUITE LIMITED AHEAD OF THIS SYSTEM THANKS TO STRONG HIGH PRESSURE
REMAINING OVER THE SERN CONUS/NRN GULF. WITH THAT LOOK FOR ISLTD TO
WIDELY SCT SHRA MAINLY WITH THE FRONT. AS FOR TEMPS LOOK FOR
SEASONABLY COOL TEMPS WITH LOWS IN THE MAINLY IN THE 40S TO MID
50S(NORTH TO SOUTH) AND HIGHS IN THE UPPER 60S/LOWER 70S MON AND TUE
AND THEN IN THE 60S BEHIND OUR FRONT ON WED.
YOUR TURKEY DAY LOOKS RATHER QUIET AND COOL. ANOTHER SURGE OF COOLER
CONTINENTAL AIR WILL BE ON THE WAY DOWN AND THIS SHOULD HELP KEEP
HIGHS IN THE UPPER 50S TO LOWER 60S. LOWS THANKSGIVING MORNING WILL
MAINLY BE IN THE 40S THANKS TO THE SFC HIGH STILL OFF TO OUR NW BUT
IF THE COOLER AIR IS A LITTLE FASTER THEN UPPER 30S WILL BE LIKELY
ACROSS THE NRN 3RD.
HIGH PRESSURE WILL DOMINATE AT THE SFC INTO THE WEEKEND AND THIS
SHOULD HELP KEEP THINGS ON THE COOL AND DRY SIDE. /CAB/
AVIATION...
CURRENT VFR CONDITIONS LIKELY TO PERSIST THROUGH THROUGH AT LEAST
SUNRISE...BEFORE LOWER CONDITIONS MOVE IN. CURRENT FORECAST MAY
ACTUALLY BE A TAD ON THE PESSIMISTIC SIDE AS LOWER CEILINGS HAVE NOT
MOVED ON SHORE YET. ONCE CONDITIONS DO FALL BELOW VFR...THEY WILL
REMAIN AT MVFR TO IFR CONDITIONS THROUGH THE REMAINDER OF THE
FORECAST PERIOD. CONVECTION SHOULD BE LIMITED...AND DO NOT PLAN ON
MENTIONING THUNDER IN TERMINALS AT THIS TIME. 35
MARINE...
MAIN CONCERN REMAINS WINDS TODAY. MOST OF THE COASTAL WATERS REMAIN
IN EXERCISE CAUTION WIND RANGES...BUT A FEW SITES OVER THE WESTERN
WATERS HAVE REACHED 20 KNOTS SUSTAINED. SPLL1...SOUTH OF TERREBONNE
PARISH REPORTING 30 KNOTS...BUT THIS IS SOMEWHAT ELEVATED WITH
ANEMOMETER AT 40 METERS...SO SURFACE WINDS LIKELY SOMEWHAT LESS.
GRADIENT FORECAST TO RELAX DURING THE DAY...AND THIS IS SHOWN IN
MODEL WIND GRIDS. WILL CARRY SCA IN WESTERN WATERS...AND EXERCISE
CAUTION EAST AND TIDAL LAKES THROUGH 00Z. EXPECT THAT THE EXERCISE
CAUTION WILL NEED TO BE CARRIED INTO THE OVERNIGHT HOURS BY THE DAY
SHIFT.
ONCE CONDITIONS RELAX OVERNIGHT TONIGHT...NO FLAGS EXPECTED BEFORE
MIDWEEK. AT THAT POINT...COLD AIR ADVECTION BEHIND NEXT FRONTAL
SYSTEM TUESDAY NIGHT OR WEDNESDAY WILL LIKELY ALLOW EXERCISE CAUTION
CONDITIONS TO RETURN. 35
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 58 49 60 48 / 100 80 10 10
BTR 58 50 62 48 / 100 40 10 10
MSY 62 53 64 51 / 100 50 10 10
GPT 60 52 65 51 / 100 80 10 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM SATURDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER TO LOWER ATCHAFALAYA RIVER LA FROM 20 TO
60 NM...AND COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER TO LOWER ATCHAFALAYA RIVER LA OUT 20 NM.
MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM SATURDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER TO LOWER ATCHAFALAYA RIVER LA FROM 20 TO
60 NM...AND COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER TO LOWER ATCHAFALAYA RIVER LA OUT 20 NM.
&&
$$
000
FXUS64 KLCH 211731
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
1131 AM CST SAT NOV 21 2009
.AVIATION...
FOR THE 21/18Z TAF ISSUANCE...
UPPER LEVEL LOW LOCATED OVER EAST CENTRAL TEXAS THIS LATE MORNING
WITH ASSOCIATED SURFACE LOW LOCATED IN THE NORTHWEST GULF ABOUT
100 MILES SOUTH-SOUTHEAST OF LAKE CHARLES. BOTH SYSTEMS WILL MOVE
SLOWLY OFF TO THE EAST-NORTHEAST TODAY AND TONIGHT. STEADY LIGHT TO MODERATE
RAIN WITH MVFR CEILINGS AND VISIBILITIES WILL CONTINUE INTO THE
AFTERNOON HOURS. RAIN IS EXPECTED TO END AT KBPT TAF SITE BY LATE
AFTERNOON...AND REMAINDER OF TAF SITES DURING THE EVENING HOURS.
AFTER THE RAIN ENDS...LOW END MVFR CEILINGS WILL PREVAIL THROUGH
THE NIGHT AS WRAP AROUND MOISTURE FROM THE UPPER LOW CONTINUES.
SOME DRIER AIR WILL GRADUALLY FILTER IN DURING THE MORNING HOURS
ON SUNDAY WITH A GRADUAL SCATTERING OUT OF THE CLOUD COVER FROM
WEST TO EAST.
RUA
&&
.PREV DISCUSSION... /ISSUED 1019 AM CST SAT NOV 21 2009/
UPDATE...NEW DISCUSSION AVAILABLE.
DISCUSSION...ANALYSIS SUGGESTING SURFACE LOW OVER THE COASTAL WATERS
CENTERED ABOUT 100 MILES SOUTH SOUTHWEST OF CAMERON. FEATURE TO
CONTINUE A NORTHEAST TRACK WITH CURRENT SCATTERED RAINS TAPERING
OFF AS THE DAY PROGRESSES. CLOUDS...RAINS AND A NORTHERLY FLOW
DEVELOPING OVER THE ENTIRE AREA WILL LIMIT ANY SIGNIFICANT WARMUP
FROM OUR CURRENT TEMPS SO A RATHER DISMAL DAY CONTINUING. GRIDS/ZONES
LOOK ON TRACK AND SEE NO NEED FOR ANY CHANGES.
MARCOTTE
PREV DISCUSSION... /ISSUED 558 AM CST SAT NOV 21 2009/
DISCUSSION...
LATEST UPPER AIR ANALYSIS/WATER VAPOR SATELLITE IMAGERY SHOWED
SPLIT FLOW ACROSS NOAM...WITH THE SUBTROPICAL JET RUNNING FROM THE
PACIFIC ACROSS NORTHERN MEXICO AND THROUGH THE CENTRAL GULF...AND
THE ACTIVE POLAR JET STREAMING ACROSS THE WESTERN AND NORTHERN
CONUS. VIGOROUS MID/UPPER LOW WAS NOTED OVER CENTRAL/EASTERN
TEXAS.
AT THE SFC...LOW PRESSURE SYSTEM CURRENTLY OVER THE NORTHWEST GULF
ABOUT 150 MILES SOUTH OF SABINE PASS...WITH HIGH PRESSURE
CENTERED OVER THE OHIO RIVER VALLEY. REGIONAL RADARS SHOW A LARGE
SWATH OF LIGHT TO MODERATE MAINLY STRATIFORM RAIN OVER THE COASTAL
WATERS AND INTO EAST TEXAS AND LOUISIANA...WITH A FEW CONVECTIVE
CELLS STARTING ABOUT 60 NM SOUTH OF GRAND CHENIER AND EXTENDING
SOUTH INTO THE GULF.
MID/UPPER LOW IS FORECAST TO CONTINUE HEADING EAST ACROSS THE
REGION TODAY...LIFTING NORTHEAST INTO CENTRAL MS TONIGHT. THE SFC
LOW IS EXPECTED TO TRACK EAST NORTHEAST ACROSS THE NORTHWEST
GULF...CROSSING SOUTHEAST LOUISIANA TONIGHT. WIDESPREAD AND
PRIMARILY ISENTROPIC LIFT DRIVEN RAINS WILL CONTINUE ON THE NORTH
SIDE OF THE SFC LOW. ISOLATED ELEVATED THUNDER IS POSSIBLE OVER
THE GULF WATERS...BUT LITTLE TO NO LIGHTNING IS EXPECTED INLAND. THE
RAINFALL WILL GRADUALLY COME TO AN END FROM WEST TO EAST THIS
AFTERNOON AND TONIGHT AS THE LOW SHIFTS EAST OF THE AREA. TOTAL
RAINFALL AMOUNTS SHOULD GENERALLY REMAIN UNDER ONE INCH.
VERY LIGHT WRAP-AROUND RAIN OR DRIZZLE IS POSSIBLE OVER EAST
CENTRAL LOUISIANA EARL SUNDAY BEFORE THE MID/UPPER SYSTEM PULLS
AWAY...BUT AT THIS TIME OPTED TO LEAVE THE FORECAST DRY. A
GENERALLY ZONAL PATTERN BEHIND THIS DEPARTING SYSTEM ALONG WITH
THE DRY AIR IT WILL HAVE BROUGHT IN WILL KEEP RAIN OUT OF THE
FORECAST ON MONDAY.
A BRIEF PERIOD OF RETURN FLOW WILL OCCUR MONDAY AFTERNOON INTO
EARLY TUESDAY AHEAD OF THE NEXT FRONTAL SYSTEM SLATED TO MOVE
THROUGH THE AREA TUESDAY AFTERNOON AND NIGHT. NEVERTHELESS...THIS
FRONT LOOKS TO BE QUITE STARVED OF MOISTURE AND THE MID/UPPER
LEVEL SUPPORT WILL PASS WELL NORTH OF THE AREA. THUS...ONLY SLIGHT
CHANCE OF RAIN IS WARRANTED AT THIS TIME. TEMPERATURES WILL CREEP
ABOVE NORMAL AHEAD OF THIS SYSTEM...BUT FALL BACK TO AT OR BELOW
NORMAL TUESDAY NIGHT AND REMAIN THERE THE REST OF THE WORK WEEK.
THANKSGIVING DAY LOOKS DRY AND MILD...WITH EARLY MORNING TEMPS IN
THE LOWER TO MID 40S AND DAYTIME HIGHS IN THE LOWER TO MID 60S.
FORECAST FOR THE WEEKEND AND BEYOND BECOMES MORE UNCERTAIN...AS
THE GLOBAL MODELS BECOME QUITE DIVERGENT IN THEIR SOLUTIONS.
SHOULD THE ECMWF PAN OUT...YET ANOTHER VIGOROUS STORM SYSTEM WOULD
AFFECT THE AREA EARLY NEXT WEEK.
MARINE...
LOW PRESSURE MOVING EAST ACROSS THE NORTHWEST GULF WILL BRING
STRONG WINDS AND ROUGH SEAS TODAY. WIDESPREAD RAIN WITH ISOLATED
THUNDERSTORMS WILL ACCOMPANY THE SYSTEM. WINDS AND RAINS WILL
DIMINISH TONIGHT INTO SATURDAY AS THE SYSTEM EXITS TO THE EAST.
GALE WARNING MAY BE BECOMING A BIT MORE MARGINAL BASED ON LATEST
OBS...BUT AT THE TIME OF EXTENSION THERE WERE STILL SOME GUSTS IN
EXCESS OF GALE FORCE BEING REPORTED. WILL CONTINUE TO MONITOR FOR
POSSIBLE CANCELLATION BEFORE THE SCHEDULED 16Z EXPIRATION TIME.
AVIATION...
AREAS OF RAIN CONTINUE TO OVERSPREAD SOUTHEAST TEXAS AND SOUTHERN
LOUISIANA AS A SFC LOW CONTINUES TO MOVE EAST NORTHEAST ACROSS THE
NW GULF. WINDS HAVE NOT STRENGTHENED AS MUCH AS INITIALLY
ANTICIPATED...BUT STILL EXPECT NE WINDS AROUND 8-12 KT THIS MORNING
AS THE LOW TREKS TOWARD SOUTHEAST LOUISIANA...GRADUALLY SHIFTING
NORTH DURING THE AFTN AND DECREASING AS IT MOVES AWAY FROM THE AREA
LATE THIS AFTN AND EVENING. PATCHY LIGHT RAIN WILL LINGER THIS
MORNING AT ALL TAF SITES...WITH OCCASIONALLY MODERATE RAINFALL
POSSIBLE ESPECIALLY AT KLFT AND KARA. IN ADDITION...MVFR CIGS
ARE EXPECTED TODAY...LOWERING TO IFR BY LATE AFTN AND EVENING
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 59 48 64 46 71 / 70 10 10 10 10
KBPT 59 47 67 48 72 / 50 10 10 10 10
KAEX 56 48 63 43 70 / 70 20 10 10 10
KLFT 59 50 62 47 69 / 80 20 10 10 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: CALCASIEU LAKE...COASTAL WATERS FROM
CAMERON, LA TO HIGH ISLAND, TX OUT 20 NM...COASTAL WATERS
FROM INTRACOASTAL CITY TO CAMERON, LA OUT 20 NM...COASTAL
WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY,
LA OUT 20 NM...SABINE LAKE...VERMILION BAY...WATERS FROM
CAMERON, LA TO HIGH ISLAND, TX EXTENDING FROM 20 NM TO 60
NM...WATERS FROM INTRACOASTAL CITY, LA TO CAMERON, LA
EXTENDING FROM 20 NM TO 60 NM...WATERS FROM LOWER
ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA EXTENDING FROM
20 NM TO 60 NM.
&&
$$
000
FXUS64 KSHV 211639
AFDSHV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
1039 AM CST SAT NOV 21 2009
.DISCUSSION...
WILL MAKE A FEW ADJUSTMENTS ON A LATE MORNING FORECAST AND GRIDS
UPDATE TO BRING THE ZONE FORECAST AND GRIDS MORE IN LINE WITH
ONGOING AND EXPECTED WEATHER FOR THIS AFTERNOON. HAVE RAISED THE
POPS IN THE SOUTHEAST ZONES FOR THE AFTERNOON BECAUSE THE UPPER
LEVEL LOW OVER THE GULF COAST NEAR BEAUMONT...AND ASSOCIATED
SURFACE LOW OUT OVER THE GULF...ARE THROWING ABUNDANT MOISTURE
NORTH INTO EAST TEXAS AND CENTRAL LOUISIANA. THIS IS CAUSING
CONSISTENT SOLID RAINFALL SOUTH OF A LINE FROM NACOGDOCHES TEXAS
TO CLARKS LOUISIANA. THIS RAIN SHOULD CONTINUE MOST OF THE
AFTEROON IN THE SAME AREA...AND TAPER OFF DURING THE EVENING AS THE
LOW PRESSURE SYSTEM MOVES EAST OF THE FOUR STATE AREA.
NORTH OF THE NACOGDOCHES TX TO CLARKS LA LINE...THE RAIN IS MORE
SCATTERED AND TENDS TO DISSIPATE AS THE RAINFALL OVER THE
SOUTH...MOVES NORTH. WILL GO WITH A 60 POP IN THE MLU AREA...40
PERCENT AT SHV...AND 30 AT TYR FOR THE AFTERNOON. IN ARKANSAS AND
SOUTHEAST OKLAHOMA 20 AND 30 PERCENT POPS SHOULD BE SUFFICIENT FOR
THE AFTERNOON. ONLY A FEW LIGHT SHOWERS AREA ANTICIPATED FOR THOSE
AREAS. ALL THE RAINFALL SHOULD MOVE EAST DURING THE EVENING...AND
OUT OF THE FOUR STATE AREA.
TEMPERATURES ARE A LITTLE WARMER THAN EARLIER FORECAST FOR THIS
AFTERNOON...SO HAVE UPPED THAT MAX TEMPERATURES FOR THIS AFTERNOON
ONE CATEGORY IN THE EAST ZONES.
NO OTHER CHANGES TO PREVIOUS FORECAST WERE MADE.
&&
.AVIATION...
SURFACE LOW OUT OVER THE GULF IS WELL OFFSHORE AND SLOWLY MOVING
EASTWARD. THE UPPER LOW IS OVER SE TX AND SHIFTING THE WINDS
ALOFT...BUT SPEEDS ARE GENERALLY LESS THAN 30 KTS BELOW FL240.
MOISTURE WRAPPING AROUND THE LOW IS MOSTLY IN THE MID LEVELS WITH
VFR CONTINUING FOR ALL BUT KLFK WHERE MODERATE RAIN IS FALLING ATTM.
CIGS ARE DROPPING A BIT IN THE WAKE OF THE LOW...BUT WILL KEEP CLOSE
TO VFR DAYLIGHT...BUT MAY GO SOUTH OVERNIGHT. SFC WINDS ARE LIGHT
N/NE FOR OUR TERMINALS AND WILL KEEP LESS THAN 10 KTS. LOOK FOR
THE RAIN CLOUDS TO PART OVERNIGHT AS THE LOW MOVES OUT...BUT IFR
CIGS/VSBY MAY DEVELOP GENERALLY ALONG AND SOUTH OF I-20 OVERNIGHT
AND FOR EARLY DAYLIGHT ON SUNDAY. IMPROVEMENTS BY LUNCH AS WEAK 1017
MB HIGH PRESSURE BUILDS IN OVER TEXAS.
/24/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 60 45 64 43 70 / 40 30 10 0 10
MLU 58 47 63 43 68 / 60 40 20 0 10
DEQ 61 41 65 42 67 / 20 20 0 0 10
TXK 60 45 64 42 69 / 30 30 0 0 10
ELD 60 45 64 42 69 / 30 40 10 0 10
TYR 60 44 67 45 71 / 30 20 0 0 10
GGG 60 43 65 44 71 / 40 20 0 0 10
LFK 58 44 67 44 72 / 60 20 0 0 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
03/24
000
FXUS64 KLCH 211619
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
1019 AM CST SAT NOV 21 2009
.UPDATE...NEW DISCUSSION AVAILABLE.
&&
.DISCUSSION...ANALYSIS SUGGESTING SURFACE LOW OVER THE COASTAL WATERS
CENTERED ABOUT 100 MILES SOUTH SOUTHWEST OF CAMERON. FEATURE TO
CONTINUE A NORTHEAST TRACK WITH CURRENT SCATTERED RAINS TAPERING
OFF AS THE DAY PROGRESSES. CLOUDS...RAINS AND A NORTHERLY FLOW
DEVELOPING OVER THE ENTIRE AREA WILL LIMIT ANY SIGNIFICANT WARMUP
FROM OUR CURRENT TEMPS SO A RATHER DISMAL DAY CONTINUING. GRIDS/ZONES
LOOK ON TRACK AND SEE NO NEED FOR ANY CHANGES.
MARCOTTE
&&
.PREV DISCUSSION... /ISSUED 558 AM CST SAT NOV 21 2009/
DISCUSSION...
LATEST UPPER AIR ANALYSIS/WATER VAPOR SATELLITE IMAGERY SHOWED
SPLIT FLOW ACROSS NOAM...WITH THE SUBTROPICAL JET RUNNING FROM THE
PACIFIC ACROSS NORTHERN MEXICO AND THROUGH THE CENTRAL GULF...AND
THE ACTIVE POLAR JET STREAMING ACROSS THE WESTERN AND NORTHERN
CONUS. VIGOROUS MID/UPPER LOW WAS NOTED OVER CENTRAL/EASTERN
TEXAS.
AT THE SFC...LOW PRESSURE SYSTEM CURRENTLY OVER THE NORTHWEST GULF
ABOUT 150 MILES SOUTH OF SABINE PASS...WITH HIGH PRESSURE
CENTERED OVER THE OHIO RIVER VALLEY. REGIONAL RADARS SHOW A LARGE
SWATH OF LIGHT TO MODERATE MAINLY STRATIFORM RAIN OVER THE COASTAL
WATERS AND INTO EAST TEXAS AND LOUISIANA...WITH A FEW CONVECTIVE
CELLS STARTING ABOUT 60 NM SOUTH OF GRAND CHENIER AND EXTENDING
SOUTH INTO THE GULF.
MID/UPPER LOW IS FORECAST TO CONTINUE HEADING EAST ACROSS THE
REGION TODAY...LIFTING NORTHEAST INTO CENTRAL MS TONIGHT. THE SFC
LOW IS EXPECTED TO TRACK EAST NORTHEAST ACROSS THE NORTHWEST
GULF...CROSSING SOUTHEAST LOUISIANA TONIGHT. WIDESPREAD AND
PRIMARILY ISENTROPIC LIFT DRIVEN RAINS WILL CONTINUE ON THE NORTH
SIDE OF THE SFC LOW. ISOLATED ELEVATED THUNDER IS POSSIBLE OVER
THE GULF WATERS...BUT LITTLE TO NO LIGHTNING IS EXPECTED INLAND. THE
RAINFALL WILL GRADUALLY COME TO AN END FROM WEST TO EAST THIS
AFTERNOON AND TONIGHT AS THE LOW SHIFTS EAST OF THE AREA. TOTAL
RAINFALL AMOUNTS SHOULD GENERALLY REMAIN UNDER ONE INCH.
VERY LIGHT WRAP-AROUND RAIN OR DRIZZLE IS POSSIBLE OVER EAST
CENTRAL LOUISIANA EARL SUNDAY BEFORE THE MID/UPPER SYSTEM PULLS
AWAY...BUT AT THIS TIME OPTED TO LEAVE THE FORECAST DRY. A
GENERALLY ZONAL PATTERN BEHIND THIS DEPARTING SYSTEM ALONG WITH
THE DRY AIR IT WILL HAVE BROUGHT IN WILL KEEP RAIN OUT OF THE
FORECAST ON MONDAY.
A BRIEF PERIOD OF RETURN FLOW WILL OCCUR MONDAY AFTERNOON INTO
EARLY TUESDAY AHEAD OF THE NEXT FRONTAL SYSTEM SLATED TO MOVE
THROUGH THE AREA TUESDAY AFTERNOON AND NIGHT. NEVERTHELESS...THIS
FRONT LOOKS TO BE QUITE STARVED OF MOISTURE AND THE MID/UPPER
LEVEL SUPPORT WILL PASS WELL NORTH OF THE AREA. THUS...ONLY SLIGHT
CHANCE OF RAIN IS WARRANTED AT THIS TIME. TEMPERATURES WILL CREEP
ABOVE NORMAL AHEAD OF THIS SYSTEM...BUT FALL BACK TO AT OR BELOW
NORMAL TUESDAY NIGHT AND REMAIN THERE THE REST OF THE WORK WEEK.
THANKSGIVING DAY LOOKS DRY AND MILD...WITH EARLY MORNING TEMPS IN
THE LOWER TO MID 40S AND DAYTIME HIGHS IN THE LOWER TO MID 60S.
FORECAST FOR THE WEEKEND AND BEYOND BECOMES MORE UNCERTAIN...AS
THE GLOBAL MODELS BECOME QUITE DIVERGENT IN THEIR SOLUTIONS.
SHOULD THE ECMWF PAN OUT...YET ANOTHER VIGOROUS STORM SYSTEM WOULD
AFFECT THE AREA EARLY NEXT WEEK.
MARINE...
LOW PRESSURE MOVING EAST ACROSS THE NORTHWEST GULF WILL BRING
STRONG WINDS AND ROUGH SEAS TODAY. WIDESPREAD RAIN WITH ISOLATED
THUNDERSTORMS WILL ACCOMPANY THE SYSTEM. WINDS AND RAINS WILL
DIMINISH TONIGHT INTO SATURDAY AS THE SYSTEM EXITS TO THE EAST.
GALE WARNING MAY BE BECOMING A BIT MORE MARGINAL BASED ON LATEST
OBS...BUT AT THE TIME OF EXTENSION THERE WERE STILL SOME GUSTS IN
EXCESS OF GALE FORCE BEING REPORTED. WILL CONTINUE TO MONITOR FOR
POSSIBLE CANCELLATION BEFORE THE SCHEDULED 16Z EXPIRATION TIME.
AVIATION...
AREAS OF RAIN CONTINUE TO OVERSPREAD SOUTHEAST TEXAS AND SOUTHERN
LOUISIANA AS A SFC LOW CONTINUES TO MOVE EAST NORTHEAST ACROSS THE
NW GULF. WINDS HAVE NOT STRENGTHENED AS MUCH AS INITIALLY
ANTICIPATED...BUT STILL EXPECT NE WINDS AROUND 8-12 KT THIS MORNING
AS THE LOW TREKS TOWARD SOUTHEAST LOUISIANA...GRADUALLY SHIFTING
NORTH DURING THE AFTN AND DECREASING AS IT MOVES AWAY FROM THE AREA
LATE THIS AFTN AND EVENING. PATCHY LIGHT RAIN WILL LINGER THIS
MORNING AT ALL TAF SITES...WITH OCCASIONALLY MODERATE RAINFALL
POSSIBLE ESPECIALLY AT KLFT AND KARA. IN ADDITION...MVFR CIGS
ARE EXPECTED TODAY...LOWERING TO IFR BY LATE AFTN AND EVENING
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 59 48 64 46 71 / 70 10 10 10 10
KBPT 59 47 67 48 72 / 50 10 10 10 10
KAEX 56 48 63 43 70 / 70 20 10 10 10
KLFT 59 50 62 47 69 / 80 20 10 10 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: CALCASIEU LAKE...COASTAL WATERS FROM
CAMERON, LA TO HIGH ISLAND, TX OUT 20 NM...COASTAL WATERS
FROM INTRACOASTAL CITY TO CAMERON, LA OUT 20 NM...COASTAL
WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY,
LA OUT 20 NM...SABINE LAKE...VERMILION BAY...WATERS FROM
CAMERON, LA TO HIGH ISLAND, TX EXTENDING FROM 20 NM TO 60
NM...WATERS FROM INTRACOASTAL CITY, LA TO CAMERON, LA
EXTENDING FROM 20 NM TO 60 NM...WATERS FROM LOWER
ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA EXTENDING FROM
20 NM TO 60 NM.
&&
$$
000
FXUS64 KLIX 211338
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
738 AM CST SAT NOV 21 2009
.UPDATE...
.SOUNDING DISCUSSION...
THE ATMOSPHERE HAS BECOME SATURATED FROM 815 MB TO 580
MB...PRECIPITABLE WATER VALUE IS 1.10 INCHES. AN ALTOSTRATUS CLOUD
DECK WAS PRESENT AT LAUNCH DUE TO QUITE A BIT OF STRATIFORM RAIN
MOVING ACROSS THE CWA ALONG WITH A FEW EMBEDDED STRONGER SHOWERS.
AN INVERSION IS PRESENT NEAR 3000 FEET WHILE WINDS ARE OUT OF THE
EAST AT THE SURFACE SHIFTING SOUTH THEN SOUTHWEST ALOFT.
&&
.PREV DISCUSSION... /ISSUED 403 AM CST SAT NOV 21 2009/
SHORT TERM...AT 9Z THE SFC LOW WAS LOCATED JUST EAST OF THE CNTRL
TX COAST AND STILL WELL SW OF THE CWA WHILE A LARGE AREA OF SHRA ARE
MAKING THERE WAY NORTH ONTO THE SWRN AND S-CNTRL LA COAST. THERE IS
AN AREA OF TSRA WELL SOUTH OF THE LA COAST AND THESE WERE MAINLY
MOVING TO THE EAST. THE MID LVL DISTURBANCE WAS STILL BACK IN ERN TX
TODAY THROUGH TOMORROW...THERE IS STILL SOME UNCERTAINTY IN THE
TRACK OF THE SFC LOW. EVEN THOUGH THE MDLS ARE WITHIN THE NOISE LVL
THE GFS IS FURTHER SOUTH THAN THE ECMWF. LOOKING AT CURRENT
FEATURES...MSAS SHOWS BEST PRESSURE FALLS EAST TO ENE OF THE SFC LOW
ALONG WITH THE STRONGEST CONVECTION WELL INTO THE GULF MOVING EAST.
THE GFES AND SREF ARE ALSO MORE IN LINE WITH THE GFS AND WITH ALL OF
THIS I PREFER THE FURTHER SOUTH TRACK. THAT SAID ANY DEVIATION
NORTH(EVEN BY JUST 50 MILES) WOULD MAKE A PRETTY GOOD DIFFERENCE IN
STRONG/SVR RISK. WITH THE TRACK EXPECTED TO REMAIN JUST OFF THE
COAST TODAY THE WARM SECTOR WILL REMAIN OVER THE COASTAL WATERS
MAKING TODAY MORE OF A ISENTROPIC LIFT/WAA SHRA DAY AND THIS SHOWS
UP REALLY WELL IN THE 290-300K LVLS FOR OUR CWA. WITH THAT SAID I
EXPECT THE LARGE AREA OF SHRA JUST OFF TO OUR SW TO CONTINUE TO
EXPAND TO THE NE THROUGH THE MORNING. THERE WILL EVEN BE ISLTD TO
SCT TSRA EMBEDDED IN THIS ACTIVITY THANKS TO ELEVATED
INSTABILITY(SHOWALTERS NEAR -3). AS FOR RAINFALL TOTALS AREA WIDE
1-2" LOOK PRETTY GOOD. THE HEAVIEST RAIN WILL LIKELY OCCUR ALONG AND
SOUTH OF A LINE FROM MORGAN CITY TO LUCEDALE THIS AFTN. THIS
LOCATION LINES UP WELL WITH THE LFQ OF A 100KT SUBTROPICAL JET.
OUR SFC LOW WILL CONTINUE TO PUSH ENE ALONG/JUST OFF THE COAST AND
SHOULD BE ALONG THE AL COAST BY TOMORROW MORNING. THIS WILL LEAD TO
VERY GOOD RAIN CHANCES ACROSS THE ERN HALF OF THE CWA THIS EVN WITH
RAIN TAPERING OFF AFTER MIDNIGHT. ACROSS THE SW WE COULD SEE RAIN
COME TO AN END QUICKLY LATE THIS AFTN/EARLY EVN AS WE SHOULD BEGIN
TO GET DRY SLOTTED. BY TOMORROW MORNING LIGHT RAIN MAY STILL BE
OCCURRING ACROSS THE EXTREME ERN PORTIONS OF THE CWA AND POSSIBLY IN
OUR OUTER WATERS. SUNDAY MAY BE A DREARY COOL DAY AS THE MID LVL
DISTURBANCE WILL BE SLOW TO LIFT OUT OF THE LOWER MS VALLEY TWRDS THE
TN VALLEY. THE LL THERMAL TROUGH WILL REMAIN WEST OF THE AREA SO WE
EXPECT TO SEE A GOOD BIT OF LOW CLOUDS STILL. /CAB/
LONG TERM...NO BIG CHANGES IN THE EXTENDED. THERE AREA SOME TIMING
DIFFERENCES B/T THE MEDIUM RANGE MDLS WITH THE PASSAGE OF THE NEXT
FRONTAL SYSTEM BUT OVERALL THE MDLS ARE IN GENERAL AGREEMENT AND
YOUR TURKEY DAY IS LOOKING RATHER QUIET ALONG THE N-CNTRL GULF COAST
AND LOWER MS VALLEY. WITH MAINLY JUST TIMING ISSUES I WILL USE A
BLEND OF THE GFS AND ECMWF WITH OUR NEXT SYSTEM
THE FIRST HALF OF THE WORK WEEK WILL BEGIN QUIET BUT ANOTHER MOSTLY
DRY FRONTAL SYSTEM WILL APPROACH THE AREA SOMETIME TUE/TUE NIGHT/WED
MORNING. BY MON NIGHT ANOTHER DISTURBANCE WILL DROP INTO THE
CNTRL/NRN PLAINS WITH A SFC LOW DEEPENING JUST WEST OF THE MID/UPPER
MS VALLEY. AS THIS SYSTEM PUSHES EAST TUE IT WILL DRAG A COLD FRONT
ACROSS THE SRN PLAINS AND INTO THE LOWER MS VALLEY. AGAIN THERE IS
SOME UNCERTAINTY AS TO WHEN THE FRONT WILL PUSH INTO THE CWA BUT IT
IS LOOKING LIKE SOMETIME TUE AFTN/EVN. NOW MOISTURE RETURN WILL BE
QUITE LIMITED AHEAD OF THIS SYSTEM THANKS TO STRONG HIGH PRESSURE
REMAINING OVER THE SERN CONUS/NRN GULF. WITH THAT LOOK FOR ISLTD TO
WIDELY SCT SHRA MAINLY WITH THE FRONT. AS FOR TEMPS LOOK FOR
SEASONABLY COOL TEMPS WITH LOWS IN THE MAINLY IN THE 40S TO MID
50S(NORTH TO SOUTH) AND HIGHS IN THE UPPER 60S/LOWER 70S MON AND TUE
AND THEN IN THE 60S BEHIND OUR FRONT ON WED.
YOUR TURKEY DAY LOOKS RATHER QUIET AND COOL. ANOTHER SURGE OF COOLER
CONTINENTAL AIR WILL BE ON THE WAY DOWN AND THIS SHOULD HELP KEEP
HIGHS IN THE UPPER 50S TO LOWER 60S. LOWS THANKSGIVING MORNING WILL
MAINLY BE IN THE 40S THANKS TO THE SFC HIGH STILL OFF TO OUR NW BUT
IF THE COOLER AIR IS A LITTLE FASTER THEN UPPER 30S WILL BE LIKELY
ACROSS THE NRN 3RD.
HIGH PRESSURE WILL DOMINATE AT THE SFC INTO THE WEEKEND AND THIS
SHOULD HELP KEEP THINGS ON THE COOL AND DRY SIDE. /CAB/
AVIATION...
CURRENT VFR CONDITIONS LIKELY TO PERSIST THROUGH THROUGH AT LEAST
SUNRISE...BEFORE LOWER CONDITIONS MOVE IN. CURRENT FORECAST MAY
ACTUALLY BE A TAD ON THE PESSIMISTIC SIDE AS LOWER CEILINGS HAVE NOT
MOVED ON SHORE YET. ONCE CONDITIONS DO FALL BELOW VFR...THEY WILL
REMAIN AT MVFR TO IFR CONDITIONS THROUGH THE REMAINDER OF THE
FORECAST PERIOD. CONVECTION SHOULD BE LIMITED...AND DO NOT PLAN ON
MENTIONING THUNDER IN TERMINALS AT THIS TIME. 35
MARINE...
MAIN CONCERN REMAINS WINDS TODAY. MOST OF THE COASTAL WATERS REMAIN
IN EXERCISE CAUTION WIND RANGES...BUT A FEW SITES OVER THE WESTERN
WATERS HAVE REACHED 20 KNOTS SUSTAINED. SPLL1...SOUTH OF TERREBONNE
PARISH REPORTING 30 KNOTS...BUT THIS IS SOMEWHAT ELEVATED WITH
ANEMOMETER AT 40 METERS...SO SURFACE WINDS LIKELY SOMEWHAT LESS.
GRADIENT FORECAST TO RELAX DURING THE DAY...AND THIS IS SHOWN IN
MODEL WIND GRIDS. WILL CARRY SCA IN WESTERN WATERS...AND EXERCISE
CAUTION EAST AND TIDAL LAKES THROUGH 00Z. EXPECT THAT THE EXERCISE
CAUTION WILL NEED TO BE CARRIED INTO THE OVERNIGHT HOURS BY THE DAY
SHIFT.
ONCE CONDITIONS RELAX OVERNIGHT TONIGHT...NO FLAGS EXPECTED BEFORE
MIDWEEK. AT THAT POINT...COLD AIR ADVECTION BEHIND NEXT FRONTAL
SYSTEM TUESDAY NIGHT OR WEDNESDAY WILL LIKELY ALLOW EXERCISE CAUTION
CONDITIONS TO RETURN. 35
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 58 49 60 48 / 100 80 10 10
BTR 58 50 62 48 / 100 40 10 10
MSY 63 53 64 51 / 100 50 10 10
GPT 60 52 65 51 / 100 90 10 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ550-570.
MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ570.
&&
$$
000
FXUS64 KLCH 211158
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
558 AM CST SAT NOV 21 2009
.DISCUSSION...
LATEST UPPER AIR ANALYSIS/WATER VAPOR SATELLITE IMAGERY SHOWED
SPLIT FLOW ACROSS NOAM...WITH THE SUBTROPICAL JET RUNNING FROM THE
PACIFIC ACROSS NORTHERN MEXICO AND THROUGH THE CENTRAL GULF...AND
THE ACTIVE POLAR JET STREAMING ACROSS THE WESTERN AND NORTHERN
CONUS. VIGOROUS MID/UPPER LOW WAS NOTED OVER CENTRAL/EASTERN
TEXAS.
AT THE SFC...LOW PRESSURE SYSTEM CURRENTLY OVER THE NORTHWEST GULF
ABOUT 150 MILES SOUTH OF SABINE PASS...WITH HIGH PRESSURE
CENTERED OVER THE OHIO RIVER VALLEY. REGIONAL RADARS SHOW A LARGE
SWATH OF LIGHT TO MODERATE MAINLY STRATIFORM RAIN OVER THE COASTAL
WATERS AND INTO EAST TEXAS AND LOUISIANA...WITH A FEW CONVECTIVE
CELLS STARTING ABOUT 60 NM SOUTH OF GRAND CHENIER AND EXTENDING
SOUTH INTO THE GULF.
MID/UPPER LOW IS FORECAST TO CONTINUE HEADING EAST ACROSS THE
REGION TODAY...LIFTING NORTHEAST INTO CENTRAL MS TONIGHT. THE SFC
LOW IS EXPECTED TO TRACK EAST NORTHEAST ACROSS THE NORTHWEST
GULF...CROSSING SOUTHEAST LOUISIANA TONIGHT. WIDESPREAD AND
PRIMARILY ISENTROPIC LIFT DRIVEN RAINS WILL CONTINUE ON THE NORTH
SIDE OF THE SFC LOW. ISOLATED ELEVATED THUNDER IS POSSIBLE OVER
THE GULF WATERS...BUT LITTLE TO NO LIGHTNING IS EXPECTED INLAND. THE
RAINFALL WILL GRADUALLY COME TO AN END FROM WEST TO EAST THIS
AFTERNOON AND TONIGHT AS THE LOW SHIFTS EAST OF THE AREA. TOTAL
RAINFALL AMOUNTS SHOULD GENERALLY REMAIN UNDER ONE INCH.
VERY LIGHT WRAP-AROUND RAIN OR DRIZZLE IS POSSIBLE OVER EAST
CENTRAL LOUISIANA EARL SUNDAY BEFORE THE MID/UPPER SYSTEM PULLS
AWAY...BUT AT THIS TIME OPTED TO LEAVE THE FORECAST DRY. A
GENERALLY ZONAL PATTERN BEHIND THIS DEPARTING SYSTEM ALONG WITH
THE DRY AIR IT WILL HAVE BROUGHT IN WILL KEEP RAIN OUT OF THE
FORECAST ON MONDAY.
A BRIEF PERIOD OF RETURN FLOW WILL OCCUR MONDAY AFTERNOON INTO
EARLY TUESDAY AHEAD OF THE NEXT FRONTAL SYSTEM SLATED TO MOVE
THROUGH THE AREA TUESDAY AFTERNOON AND NIGHT. NEVERTHELESS...THIS
FRONT LOOKS TO BE QUITE STARVED OF MOISTURE AND THE MID/UPPER
LEVEL SUPPORT WILL PASS WELL NORTH OF THE AREA. THUS...ONLY SLIGHT
CHANCE OF RAIN IS WARRANTED AT THIS TIME. TEMPERATURES WILL CREEP
ABOVE NORMAL AHEAD OF THIS SYSTEM...BUT FALL BACK TO AT OR BELOW
NORMAL TUESDAY NIGHT AND REMAIN THERE THE REST OF THE WORK WEEK.
THANKSGIVING DAY LOOKS DRY AND MILD...WITH EARLY MORNING TEMPS IN
THE LOWER TO MID 40S AND DAYTIME HIGHS IN THE LOWER TO MID 60S.
FORECAST FOR THE WEEKEND AND BEYOND BECOMES MORE UNCERTAIN...AS
THE GLOBAL MODELS BECOME QUITE DIVERGENT IN THEIR SOLUTIONS.
SHOULD THE ECMWF PAN OUT...YET ANOTHER VIGOROUS STORM SYSTEM WOULD
AFFECT THE AREA EARLY NEXT WEEK.
&&
.MARINE...
LOW PRESSURE MOVING EAST ACROSS THE NORTHWEST GULF WILL BRING
STRONG WINDS AND ROUGH SEAS TODAY. WIDESPREAD RAIN WITH ISOLATED
THUNDERSTORMS WILL ACCOMPANY THE SYSTEM. WINDS AND RAINS WILL
DIMINISH TONIGHT INTO SATURDAY AS THE SYSTEM EXITS TO THE EAST.
GALE WARNING MAY BE BECOMING A BIT MORE MARGINAL BASED ON LATEST
OBS...BUT AT THE TIME OF EXTENSION THERE WERE STILL SOME GUSTS IN
EXCESS OF GALE FORCE BEING REPORTED. WILL CONTINUE TO MONITOR FOR
POSSIBLE CANCELLATION BEFORE THE SCHEDULED 16Z EXPIRATION TIME.
&&
.AVIATION...
AREAS OF RAIN CONTINUE TO OVERSPREAD SOUTHEAST TEXAS AND SOUTHERN
LOUISIANA AS A SFC LOW CONTINUES TO MOVE EAST NORTHEAST ACROSS THE
NW GULF. WINDS HAVE NOT STRENGTHENED AS MUCH AS INITIALLY
ANTICIPATED...BUT STILL EXPECT NE WINDS AROUND 8-12 KT THIS MORNING
AS THE LOW TREKS TOWARD SOUTHEAST LOUISIANA...GRADUALLY SHIFTING
NORTH DURING THE AFTN AND DECREASING AS IT MOVES AWAY FROM THE AREA
LATE THIS AFTN AND EVENING. PATCHY LIGHT RAIN WILL LINGER THIS
MORNING AT ALL TAF SITES...WITH OCCASIONALLY MODERATE RAINFALL
POSSIBLE ESPECIALLY AT KLFT AND KARA. IN ADDITION...MVFR CIGS
ARE EXPECTED TODAY...LOWERING TO IFR BY LATE AFTN AND EVENING
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 59 48 64 46 / 70 10 10 10
KBPT 59 47 67 48 / 50 10 10 10
KAEX 56 48 63 43 / 70 20 10 10
KLFT 59 50 62 47 / 80 20 10 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 6 PM CST THIS
EVENING FOR COASTAL WATERS FROM CAMERON, LA TO HIGH ISLAND,
TX OUT 20 NM-COASTAL WATERS FROM INTRACOASTAL CITY TO
CAMERON, LA OUT 20 NM-COASTAL WATERS FROM LOWER ATCHAFALAYA
RIVER TO INTRACOASTAL CITY, LA OUT 20 NM-WATERS FROM
CAMERON, LA TO HIGH ISLAND, TX EXTENDING FROM 20 NM TO 60
NM-WATERS FROM INTRACOASTAL CITY, LA TO CAMERON, LA
EXTENDING FROM 20 NM TO 60 NM-WATERS FROM LOWER ATCHAFALAYA
RIVER TO INTRACOASTAL CITY, LA EXTENDING FROM 20 NM TO 60
NM.
GALE WARNING UNTIL 10 AM CST THIS MORNING FOR COASTAL WATERS
FROM CAMERON, LA TO HIGH ISLAND, TX OUT 20 NM-COASTAL
WATERS FROM INTRACOASTAL CITY TO CAMERON, LA OUT 20 NM-
COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL
CITY, LA OUT 20 NM-WATERS FROM CAMERON, LA TO HIGH ISLAND,
TX EXTENDING FROM 20 NM TO 60 NM-WATERS FROM INTRACOASTAL
CITY, LA TO CAMERON, LA EXTENDING FROM 20 NM TO 60 NM-
WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY,
LA EXTENDING FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR CALCASIEU
LAKE-SABINE LAKE-VERMILION BAY.
&&
$$
PUBLIC/MARINE...13
AVIATION...24
000
FXUS64 KSHV 211115
AFDSHV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
515 AM CST SAT NOV 21 2009
.DISCUSSION...
EARLY THIS MORNING THE MID AND UPPER LEVEL LOW WAS INDICATED TO BE
SPINNING OVER CENTRAL TEXAS THIS MORNING AND WILL SLOWLY MOVE EAST
CROSSING THE FOUR STATE REGION LATE THIS AFTERNOON AND APPROACHING THE
TENNESSEE VALLEY REGION OF NORTH ALABAMA BY EARLY SUNDAY MORNING.
THE LOW WILL THEN RIDE INTO THE BACK OF A RIDGE OF HIGH PRESSURE
OVER THE NORTHEAST SECTIONS OF THE COUNTRY AND BECOME AN OPEN WAVE
AS IT MOVES ON TO THE NORTHEAST BY EARL MONDAY. A SURFACE LOW OFF THE
MIDDLE AND UPPER TEXAS WILL MOVE EAST NORTHEAST ACROSS THE
NORTHERN GULF OF MEXICO AHEAD OF THE UPPER SYSTEM AND ACROSS
NORTHERN FLORIDA BY EARLY MONDAY. THE FOUR STATE REGION WILL
CONTINUE TO SEE LIGHT RAIN OR SHOWERS THROUGH TODAY...THEN A
GRADUAL DECREASE IN RAIN FROM WEST TO EAST OVERNIGHT WITH ONLY A
VERY SMALL AREA WITH POSSIBLE LIGHT RAIN EARLY SUNDAY. BY
AFTERNOON SUNDAY EXPECTING MOST ALL THE RAIN TO BE EXITING OFF TO
THE EAST. HIGH PRESSURE WILL BUILD INTO THE FORECAST AREA WHICH
WILL HOLD INTO THE EARLY START TO THE WORK WEEK. ANOTHER COLD FRONT
WILL MOVE THROUGH LATE MONDAY NIGHT INTO TUESDAY RETURNING RAIN
CHANCES...BUT ONCE THIS SYSTEM EXISTS TO THE EAST WE WILL BE
EXPECTING COOLER BUT DRIER WEATHER. AN UPPER LEVEL RIDGE OF HIGH
PRESSURE WILL AMPLIFY OVER THE WESTERN STATES WITH A LARGE SURFACE
RIDGE OF HIGH PRESSURE BUILDING SOUTH INTO THE FOUR STATE REGION
KEEPING A DRY PATTERN INTO THE WEEKEND. SOME OF THE COOLER WEATHER
WILL BE AROUND FOR THE START OF THANKSGIVING HOLIDAY INTO FRIDAY. /06/
&&
.AVIATION...
OFF AND ON LIGHT RAIN SHOWERS WILL CONTINUE OVER MUCH OF THE FOUR
STATE REGION THIS MORNING. THIS WILL CONTINUE THROUGH AT LEAST THIS
AFTERNOON FOR THE MAJORITY OF THE TAF SITES. THIS ACTIVITY SHOULD
DECREASE FROM WEST TO EAST THIS EVENING...LEAVING EASTERN SITES BY
THE EARLY MORNING HOURS SUNDAY. CIGS OVERALL HAVE REMAINED ABOVE 3
KFT TO GIVE PREVAILING VFR CIGS. VSBYS HAVE GENERALLY REMAINED
BETWEEN MVFR AND VFR FLIGHT CATEGORIES. THIS IS EXPECTED TO CONTINUE
THROUGH THE REMAINDER OF THE OVERNIGHT HOURS AND INTO THE EARLY
AFTERNOON. HOWEVER...CAN NOT RULE OUT PERIODS WHEN THE CIGS DROP TO
AROUND 2-3 KFT...ESPECIALLY DURING THE EARLY MORNING HOURS. THIS
POSSIBILITY WILL BE COVERED BY TEMPO GROUPS. CLOUD COVER IS EXPECTED
TO BEGIN BREAKING UP FROM WEST TO EAST LATE THIS EVENING AND INTO
SUNDAY. OTHERWISE EXPECT WINDS TO BE LIGHT GENERALLY OUT OF THE EAST
TO NORTHEAST FOR THE MAJORITY OF THE FORECAST PERIOD. /22/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 58 45 64 43 70 / 60 30 10 0 10
MLU 56 47 63 43 68 / 60 40 20 0 10
DEQ 61 41 65 42 67 / 40 20 0 0 10
TXK 60 45 64 42 69 / 50 30 0 0 10
ELD 58 45 64 42 69 / 50 40 10 0 10
TYR 60 44 67 45 71 / 50 20 0 0 10
GGG 59 43 65 44 71 / 50 20 0 0 10
LFK 60 44 67 44 72 / 60 20 0 0 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
06/22
000
FXUS64 KLIX 211003
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
403 AM CST SAT NOV 21 2009
.SHORT TERM...AT 9Z THE SFC LOW WAS LOCATED JUST EAST OF THE CNTRL
TX COAST AND STILL WELL SW OF THE CWA WHILE A LARGE AREA OF SHRA ARE
MAKING THERE WAY NORTH ONTO THE SWRN AND S-CNTRL LA COAST. THERE IS
AN AREA OF TSRA WELL SOUTH OF THE LA COAST AND THESE WERE MAINLY
MOVING TO THE EAST. THE MID LVL DISTURBANCE WAS STILL BACK IN ERN TX
TODAY THROUGH TOMORROW...THERE IS STILL SOME UNCERTAINTY IN THE
TRACK OF THE SFC LOW. EVEN THOUGH THE MDLS ARE WITHIN THE NOISE LVL
THE GFS IS FURTHER SOUTH THAN THE ECMWF. LOOKING AT CURRENT
FEATURES...MSAS SHOWS BEST PRESSURE FALLS EAST TO ENE OF THE SFC LOW
ALONG WITH THE STRONGEST CONVECTION WELL INTO THE GULF MOVING EAST.
THE GFES AND SREF ARE ALSO MORE IN LINE WITH THE GFS AND WITH ALL OF
THIS I PREFER THE FURTHER SOUTH TRACK. THAT SAID ANY DEVIATION
NORTH(EVEN BY JUST 50 MILES) WOULD MAKE A PRETTY GOOD DIFFERENCE IN
STRONG/SVR RISK. WITH THE TRACK EXPECTED TO REMAIN JUST OFF THE
COAST TODAY THE WARM SECTOR WILL REMAIN OVER THE COASTAL WATERS
MAKING TODAY MORE OF A ISENTROPIC LIFT/WAA SHRA DAY AND THIS SHOWS
UP REALLY WELL IN THE 290-300K LVLS FOR OUR CWA. WITH THAT SAID I
EXPECT THE LARGE AREA OF SHRA JUST OFF TO OUR SW TO CONTINUE TO
EXPAND TO THE NE THROUGH THE MORNING. THERE WILL EVEN BE ISLTD TO
SCT TSRA EMBEDDED IN THIS ACTIVITY THANKS TO ELEVATED
INSTABILITY(SHOWALTERS NEAR -3). AS FOR RAINFALL TOTALS AREA WIDE
1-2" LOOK PRETTY GOOD. THE HEAVIEST RAIN WILL LIKELY OCCUR ALONG AND
SOUTH OF A LINE FROM MORGAN CITY TO LUCEDALE THIS AFTN. THIS
LOCATION LINES UP WELL WITH THE LFQ OF A 100KT SUBTROPICAL JET.
OUR SFC LOW WILL CONTINUE TO PUSH ENE ALONG/JUST OFF THE COAST AND
SHOULD BE ALONG THE AL COAST BY TOMORROW MORNING. THIS WILL LEAD TO
VERY GOOD RAIN CHANCES ACROSS THE ERN HALF OF THE CWA THIS EVN WITH
RAIN TAPERING OFF AFTER MIDNIGHT. ACROSS THE SW WE COULD SEE RAIN
COME TO AN END QUICKLY LATE THIS AFTN/EARLY EVN AS WE SHOULD BEGIN
TO GET DRY SLOTTED. BY TOMORROW MORNING LIGHT RAIN MAY STILL BE
OCCURRING ACROSS THE EXTREME ERN PORTIONS OF THE CWA AND POSSIBLY IN
OUR OUTER WATERS. SUNDAY MAY BE A DREARY COOL DAY AS THE MID LVL
DISTURBANCE WILL BE SLOW TO LIFT OUT OF THE LOWER MS VALLEY TWRDS THE
TN VALLEY. THE LL THERMAL TROUGH WILL REMAIN WEST OF THE AREA SO WE
EXPECT TO SEE A GOOD BIT OF LOW CLOUDS STILL. /CAB/
.LONG TERM...NO BIG CHANGES IN THE EXTENDED. THERE AREA SOME TIMING
DIFFERENCES B/T THE MEDIUM RANGE MDLS WITH THE PASSAGE OF THE NEXT
FRONTAL SYSTEM BUT OVERALL THE MDLS ARE IN GENERAL AGREEMENT AND
YOUR TURKEY DAY IS LOOKING RATHER QUIET ALONG THE N-CNTRL GULF COAST
AND LOWER MS VALLEY. WITH MAINLY JUST TIMING ISSUES I WILL USE A
BLEND OF THE GFS AND ECMWF WITH OUR NEXT SYSTEM
THE FIRST HALF OF THE WORK WEEK WILL BEGIN QUIET BUT ANOTHER MOSTLY
DRY FRONTAL SYSTEM WILL APPROACH THE AREA SOMETIME TUE/TUE NIGHT/WED
MORNING. BY MON NIGHT ANOTHER DISTURBANCE WILL DROP INTO THE
CNTRL/NRN PLAINS WITH A SFC LOW DEEPENING JUST WEST OF THE MID/UPPER
MS VALLEY. AS THIS SYSTEM PUSHES EAST TUE IT WILL DRAG A COLD FRONT
ACROSS THE SRN PLAINS AND INTO THE LOWER MS VALLEY. AGAIN THERE IS
SOME UNCERTAINTY AS TO WHEN THE FRONT WILL PUSH INTO THE CWA BUT IT
IS LOOKING LIKE SOMETIME TUE AFTN/EVN. NOW MOISTURE RETURN WILL BE
QUITE LIMITED AHEAD OF THIS SYSTEM THANKS TO STRONG HIGH PRESSURE
REMAINING OVER THE SERN CONUS/NRN GULF. WITH THAT LOOK FOR ISLTD TO
WIDELY SCT SHRA MAINLY WITH THE FRONT. AS FOR TEMPS LOOK FOR
SEASONABLY COOL TEMPS WITH LOWS IN THE MAINLY IN THE 40S TO MID
50S(NORTH TO SOUTH) AND HIGHS IN THE UPPER 60S/LOWER 70S MON AND TUE
AND THEN IN THE 60S BEHIND OUR FRONT ON WED.
YOUR TURKEY DAY LOOKS RATHER QUIET AND COOL. ANOTHER SURGE OF COOLER
CONTINENTAL AIR WILL BE ON THE WAY DOWN AND THIS SHOULD HELP KEEP
HIGHS IN THE UPPER 50S TO LOWER 60S. LOWS THANKSGIVING MORNING WILL
MAINLY BE IN THE 40S THANKS TO THE SFC HIGH STILL OFF TO OUR NW BUT
IF THE COOLER AIR IS A LITTLE FASTER THEN UPPER 30S WILL BE LIKELY
ACROSS THE NRN 3RD.
HIGH PRESSURE WILL DOMINATE AT THE SFC INTO THE WEEKEND AND THIS
SHOULD HELP KEEP THINGS ON THE COOL AND DRY SIDE. /CAB/
&&
.AVIATION...
CURRENT VFR CONDITIONS LIKELY TO PERSIST THROUGH THROUGH AT LEAST
SUNRISE...BEFORE LOWER CONDITIONS MOVE IN. CURRENT FORECAST MAY
ACTUALLY BE A TAD ON THE PESSIMISTIC SIDE AS LOWER CEILINGS HAVE NOT
MOVED ON SHORE YET. ONCE CONDITIONS DO FALL BELOW VFR...THEY WILL
REMAIN AT MVFR TO IFR CONDITIONS THROUGH THE REMAINDER OF THE
FORECAST PERIOD. CONVECTION SHOULD BE LIMITED...AND DO NOT PLAN ON
MENTIONING THUNDER IN TERMINALS AT THIS TIME. 35
&&
.MARINE...
MAIN CONCERN REMAINS WINDS TODAY. MOST OF THE COASTAL WATERS REMAIN
IN EXERCISE CAUTION WIND RANGES...BUT A FEW SITES OVER THE WESTERN
WATERS HAVE REACHED 20 KNOTS SUSTAINED. SPLL1...SOUTH OF TERREBONNE
PARISH REPORTING 30 KNOTS...BUT THIS IS SOMEWHAT ELEVATED WITH
ANEMOMETER AT 40 METERS...SO SURFACE WINDS LIKELY SOMEWHAT LESS.
GRADIENT FORECAST TO RELAX DURING THE DAY...AND THIS IS SHOWN IN
MODEL WIND GRIDS. WILL CARRY SCA IN WESTERN WATERS...AND EXERCISE
CAUTION EAST AND TIDAL LAKES THROUGH 00Z. EXPECT THAT THE EXERCISE
CAUTION WILL NEED TO BE CARRIED INTO THE OVERNIGHT HOURS BY THE DAY
SHIFT.
ONCE CONDITIONS RELAX OVERNIGHT TONIGHT...NO FLAGS EXPECTED BEFORE
MIDWEEK. AT THAT POINT...COLD AIR ADVECTION BEHIND NEXT FRONTAL
SYSTEM TUESDAY NIGHT OR WEDNESDAY WILL LIKELY ALLOW EXERCISE CAUTION
CONDITIONS TO RETURN. 35
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 58 49 60 48 / 100 80 10 10
BTR 58 50 62 48 / 100 40 10 10
MSY 62 53 64 51 / 100 50 10 10
GPT 60 52 65 51 / 100 80 10 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM SATURDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER TO LOWER ATCHAFALAYA RIVER LA FROM 20 TO
60 NM...AND COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER TO LOWER ATCHAFALAYA RIVER LA OUT 20 NM.
MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM SATURDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER TO LOWER ATCHAFALAYA RIVER LA FROM 20 TO
60 NM...AND COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER TO LOWER ATCHAFALAYA RIVER LA OUT 20 NM.
&&
$$
SHORT TERM/LONG TERM: CAB
AVIATION/MARINE: 35
000
FXUS64 KLCH 210558
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
1158 PM CST FRI NOV 20 2009
.AVIATION...
SFC LOW NOW APPEARS TO BE CENTERED OFF THE TX COAST...ABOUT 60 NM
SOUTHEAST OF MATAGORDA BAY...IN THE VICINITY OF STRONGER
CONVECTION IN THE WESTERN GULF. LOW IS STILL EXPECTED TO TRACK
ACRS THE NW GULF...TOWARD SOUTHERN OR SOUTHEASTERN LA...REMAINING
SOUTH OF OUR TAF SITES. RADAR CURRENTLY SHOWS JUST PATCHY LIGHT
RAIN OVER LA AND SE TX WITH AN AREA OF HEAVIER RAIN OFFSHORE.
EXPECT RAINFALL TO INCREASE IN AREA TONIGHT OVER SOUTHERN TAF
SITES AS THE LOW MOVES CLOSER TO THE COAST...WITH HEAVIEST
RAINFALL TO REMAIN OFFSHORE. CIGS AND VISBYS ALSO EXPECTED TO
LOWER TO MVFR TONIGHT AS RAIN AREA INCREASES. IN
ADDITION...NORTHEAST WINDS ARE EXPECTED TO STRENGTHEN TO BETWEEN
10-15 KT TONIGHT...GRADUALLY SHIFTING TO THE NORTH BY MIDDAY
SATURDAY AT KBPT AND KLCH...AND MID AFTERNOON AT KAEX...KLFT AND
KARA. CONDITIONS SHOULD BEGIN TO IMPROVE LATE SATURDAY AS THE LOW
SYSTEM MOVES NORTHEAST OF THE AREA. 24
&&
.PREV DISCUSSION... /ISSUED 921 PM CST FRI NOV 20 2009/
DISCUSSION...
LATEST SFC ANALYSIS SHOWS A BROAD AREA OF LOW PRESSURE OFF THE
MIDDLE TX COAST WHILE WATER VAPOR IMAGERY SHOWS SHORTWAVE TROF
CROSSING CNTL TEXAS. WEAK VORTS ROUNDING THE SHORTWAVE EVIDENT IN
CLUSTERS OF RAIN...ONE CURRENTLY MOVING OUT OF S-CNTL LA AND INTO
SERN LA WITH ANOTHER LARGER AREA MOVING ALONG THE UPPER TX COAST
TOWARD SERN TEXAS. YET ANOTHER ROUND OF RAIN SHOWING UP OVER CNTL
TX NEAR THE MAIN SHORTWAVE TROF. SOME CONVECTION NOTED WITHIN THE
RAIN SHIELD OVER THE NWRN GULF IN VICINITY OF THE SFC LOW.
MAIN CHANGE TO THE FORECAST TONIGHT IS TO REMOVE MENTION OF
THUNDER OVER MOST OF THE FORECAST AREA AS CONDITIONS LOOK TOO
STABLE. HOWEVER LEFT MENTION OF ISOLATED THUNDER OVER THE SERN
ZONES AS STORMS OFFSHORE COULD MOVE ASHORE INTO THIS REGION LATER
TONIGHT GIVEN CURRENT AND FORECAST TRAJECTORIES. OTHERWISE GOING
FORECASTS LOOK GOOD WITH RAIN A GOOD BET OVERNIGHT. TEMPS/WINDS
LOOK FINE AS IS AND NO CHANGES PLANNED THERE.
UPDATE OUT SHORTLY.
25
PREV DISCUSSION... /ISSUED 553 PM CST FRI NOV 20 2009/
AVIATION...
AN AREA OF LIGHT RAIN WAS MOVING EAST ACRS SRN LA...MAINLY
AFFECTING SERN TAF SITES. WILL SEE A BREAK EARLY THIS EVENING WITH
THE NEXT ROUND OF LIGHT RAIN EXPECTED TO MOVE INTO THE NW GULF AND
ACRS SRN AREAS LATE THIS EVENING INTO THE OVERNIGHT HOURS. THIS
RAINFALL IS THE RESULT OF AN UPPER LEVEL TROUGH AND ASSOCIATED SFC
LOW NEAR THE TX COAST THAT WILL LIFT NE ACRS THE AREA TONIGHT INTO
EARLY SATURDAY. EXPECT PERIODS OF MAINLY LIGHT RAIN BEGINNING
AROUND 02Z AT KBPT...WITH RAINFALL PROGRESSING EAST ACRS KLCH AND
INTO KLFT AND KARA FROM 03Z-06Z. VFR CIGS AND VISBYS EXPECTED AT
KAEX. VFR ALSO EXPECTED AT KLFT AND KARA THROUGH LATE
TONIGHT...BECOMING MVFR BETWEEN 10Z-12Z...WHILE GENERALLY MVFR
CONDITIONS TO PREVAIL THROUGHOUT THE PERIOD AT KLCH AND KBPT.
IN ADDITION...AS THE SFC LOW DEVELOPS AND MOVES TOWARD THE AREA
TONIGHT...A TIGHTENING GRADIENT WILL PRODUCE BREEZY NORTHEASTERLY
WINDS WITH POSSIBLE GUSTS BETWEEN 20 AND 25 KTS OVERNIGHT INTO
EARLY SATURDAY MAINLY FOR SRN TAF SITES. 24
PREV DISCUSSION... /ISSUED 435 PM CST FRI NOV 20 2009/
DISCUSSION...RATHER CHALLENGING FORECAST AND HENCE RUNNING A
LITTLE LATE. WAS HOPING FOR BETTER CONTINUITY BETWEEN MODELS...PARTICULARLY
THE EMCWF AND GFS...BUT THIS DID NOT OCCUR. HAVE TRENDED TOWARD
THE GFS SOLUTION WHICH WAS OFFERED SOME SUPPORT BY THE LOCAL WRF
MODEL AS WELL AS HPC. THUS A MORE PROGRESSIVE AND SHORTER-LIVED EVENT
THAN ADVERTISED BY THE EUROPEAN MODEL.
RADAR SHOWING LIGHT TO MODERATE RAINS OVER SOUTH LOUISIANA
ADVANCING EAST. EXPECTING SECONDARY BATCH OF RAINS TO ADVANCE
ACROSS THE AREA OVERNIGHT SO CARRYING CATEGORICAL POPS
SOUTH...LIKELY NORTH. PRIMARILY LOOKING AT OVER-RUNNING RAINS AND
ANY LIGHTNING ACTIVITY TO BE BE MINIMAL AT MOST. RAINS AMOUNTS OF
1 TO 2 INCHES EXPECTED ALONG THE INTERSTATE 10 CORRIDOR SOUTH...AND
LESSER AMOUNTS FURTHER NORTH.
RAINS TAPER OFF SATURDAY WITH SYSTEM ADVANCING EAST. REMAINDER OF
WEEKEND LOOKING DRY AND COOL WITH A NORTHERLY FLOW REMAINING IN
PLACE. NEXT POTENTIAL FROPA AND RAIN-MAKER COMING TUESDAY.
MARINE...LOW PRESSURE DEEPENING AND MOVING ACROSS THE NORTHWEST GULF WILL
BRING STRENGTHENING WINDS AND BUILDING SEAS TONIGHT. WIDESPREAD
RAIN WILL ACCOMPANY THE SYSTEM. WINDS AND RAINS WILL DIMINISH
SATURDAY AS THE SYSTEM EXITS EAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 50 63 46 71 / 80 40 10 10
KBPT 51 65 46 71 / 60 30 10 10
KAEX 50 62 43 68 / 60 40 10 10
KLFT 52 60 47 67 / 80 50 10 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM CST SATURDAY FOR COASTAL
WATERS FROM CAMERON, LA TO HIGH ISLAND, TX OUT 20 NM-
COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON, LA OUT 20
NM-COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO
INTRACOASTAL CITY, LA OUT 20 NM-WATERS FROM CAMERON, LA TO
HIGH ISLAND, TX EXTENDING FROM 20 NM TO 60 NM-WATERS FROM
INTRACOASTAL CITY, LA TO CAMERON, LA EXTENDING FROM 20 NM
TO 60 NM-WATERS FROM LOWER ATCHAFALAYA RIVER TO
INTRACOASTAL CITY, LA EXTENDING FROM 20 NM TO 60 NM.
GALE WARNING UNTIL 6 AM CST SATURDAY FOR COASTAL WATERS FROM
CAMERON, LA TO HIGH ISLAND, TX OUT 20 NM-COASTAL WATERS
FROM INTRACOASTAL CITY TO CAMERON, LA OUT 20 NM-COASTAL
WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY,
LA OUT 20 NM-WATERS FROM CAMERON, LA TO HIGH ISLAND, TX
EXTENDING FROM 20 NM TO 60 NM-WATERS FROM INTRACOASTAL
CITY, LA TO CAMERON, LA EXTENDING FROM 20 NM TO 60 NM-
WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY,
LA EXTENDING FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 6 AM CST SATURDAY FOR CALCASIEU LAKE-
SABINE LAKE-VERMILION BAY.
&&
$$
000
FXUS64 KLIX 210544
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1144 PM CST FRI NOV 20 2009
.AVIATION...
MAINLY JUST SPRINKLES FALLING FROM MID LEVELS CLOUDS WERE
OCCASIONALLY BEING OBSERVED AT THE TAF SITES AS A LAYER OF DRY AIR
IN THE LOWER LEVELS PREVAILED ACROSS THE FORECAST AREA LATE THIS
EVENING. AS THE COLUMN BECOMES SATURATED OVERNIGHT...MORE IN THE
WAY OF LIGHT RAIN WILL BE OBSERVED TOWARD MORNING. THIS FIRST
BATCH OF LIGHT RAIN WAS RESULTING FROM A LEAD SHORT WAVE MOVING
ACROSS THE REGION. MORE SUBSTANTIAL RAIN WAS OCCURRING TO THE
SOUTHWEST OF LAKE CHARLES AND THIS RAIN WILL GRADUALLY MAKE ITS
WAY INTO THE FORECAST AREA LATE TONIGHT AND SATURDAY MORNING.
OCCASIONAL LIGHT RAIN CAN BE EXPECTED AT THE TERMINAL SITES DURING
THE DAY SATURDAY. THE LATEST MODEL GUIDANCE APPEARS TO BE SOMEWHAT
SLOWER IN MOVING THE RAIN OUT OF THE AREA...THEREFORE RAIN MAY
LINGER THROUGH SATURDAY EVENING AT MOST LOCATIONS. VFR CEILINGS TONIGHT
WILL LOWER TO MVFR CEILINGS DURING THE MID AND LATE MORNING HOURS
SATURDAY...AND THEN INTO THE IFR RANGE SATURDAY EVENING. LIGHT
RAIN AND LIGHT FOG WILL RESULT IN MVFR VISIBILITIES DURING MUCH OF
THE DAY SATURDAY. 11
&&
.PREV DISCUSSION... /ISSUED 911 PM CST FRI NOV 20 2009/
UPDATE...
THERE IS FINALLY SOME WEATHER TO TALK ABOUT THIS EVENING. A
SERIES OF WELL DEFINED UPPER LEVEL DISTURBANCES ARE MOVING EAST
ACROSS THE WESTERN GULF COAST REGION. THE LEAD SHORTWAVE IS
NEAR THE WESTERN BORDER OF THE FORECAST AREA AND IS PRECEDED BY
PATCHY LIGHT RAIN...MOSTLY FALLING AS SPRINKLES WITH ONLY TRACE
RAINFALL AMOUNTS REPORTED THUS FAR DUE TO THE VERY DRY AIR BELOW
700 MB. THERE IS LIKELY SOME MEASURABLE LIGHT RAIN REACHING THE
GROUND OVER THE COASTAL WATERS FROM SOUTHWEST PASS TO THE LOWER
ATCHAFALAYA RIVER. DEEPER CONVECTION WITH LIGHTNING IS OCCURRING
FARTHER OFFSHORE NEAR THE MIDDLE BUOY /42001/.
THERE IS A BREAK BEHIND THIS FIRST DISTURBANCE WITH NO RAIN
CURRENTLY BEING REPORTED ACROSS MUCH OF SOUTHWEST LOUISIANA.
RADAR SHOWS ONLY ISOLATED SHOWER ACTIVITY OFF THE COAST OF
SOUTHWEST LOUISIANA.
FARTHER WEST...THE MAIN...STRONGER SHORTWAVE TROUGH AND DEVELOPING
UPPER LOW IS OVER CENTRAL TEXAS AND PRECEDED BY ANOTHER
DISTURBANCE AND THE MAIN SURFACE LOW NEAR THE CENTRAL TEXAS COAST.
THUNDERSTORMS ASSOCIATED WITH THIS DISTURBANCE EXTEND FARTHER
NORTH...BUT ARE MOSTLY ELEVATED. THIS SYSTEM PRODUCED OVER 10
INCHES OF RAIN ALONG PORTIONS OF THE CENTRAL TEXAS COAST LAST
NIGHT AND THIS MORNING.
THE COMPLICATING PART OF THIS UPDATE IS HOW TO DESCRIBE THE RAIN
TRENDS TONIGHT WITH THE AFOREMENTIONED FEATURES IN THE PREVIOUS
PARAGRAPHS. THE BEST WAY TO DESCRIBE THE FORECAST IS A FEW
SPRINKLES WITH A SLIGHT CHANCE OF BARELY MEASURABLE /.01 INCHES/
EARLY ON...TRENDING TOWARDS MORE STEADY RAIN IN SOME SOUTHERN
AREAS...BUT THEN ONLY A SLIGHT CHANCE OF SHOWERS FOR SEVERAL
HOURS BETWEEN SHORTWAVES...FOLLOWED BY MORE WIDESPREAD RAIN AND
SHOWERS SPREADING FROM WEST TO EAST AFTER MIDNIGHT AS ISENTROPIC
LIFT INCREASES AHEAD OF THE SECOND DISTURBANCE AND APPROACHING
SURFACE LOW. HAVING SAID THAT...HAVE PLACED WORDING OF SPRINKLES
EARLY ON IN THE ZONE FORECAST THEN TRENDED TOWARDS THE MORE
NUMEROUS TO WIDESPREAD SHOWERS IN THE WESTERN AND CENTRAL ZONES
LATER ON TONIGHT. A NOTE ABOUT THE MODELS...THE 18Z GFS WILL
VERIFY HORRIBLY WITH ITS HEAVY RAIN THAT IS SHOWS THIS EVENING
OVER SOUTHERN PORTIONS OF SOUTHEAST LOUISIANA.
LOOKING AT WINDS...THEY HAVE BEEN TRENDING A BIT LIGHTER THAN
FORECAST...SO DO NOT SEE THE REASON TO RAISE THE SMALL CRAFT
ADVISORY /SCA/ FLAGS JUST YET. THE NEXT SHIFT WILL HAVE TO
MONITOR NEW DATA AND DECIDE IF A SCA IS NEEDED ON SATURDAY.
ON SATURDAY...ALSO MADE SOME ADJUSTMENTS TO INCLUDE ISOLATED TO
SCATTERED THUNDERSTORMS OVER MAINLY COASTAL LAND AREAS AND SOME
INLAND PARISHES AND COUNTIES TO BE CONSISTENT WITH SPC. MODEL
SOUNDINGS SHOW VERY ELEVATED INSTABILITY LIFTING FROM 750-700
EARLY MORNING LOWERING TO 850-800 MB IN THE AFTERNOON BEFORE DRIER
AIR DIMINISHES THE POPS LATE IN THE AFTERNOON. IT APPEARS ANY
TRUE SURFACE BASED INSTABILITY WILL REMAIN WELL OFFSHORE EVEN IF
THE SURFACE LOW TRACKS SLIGHTLY INLAND...OWING TO THE LINGERING
EFFECTS OF CURRENT DRY AIR IN THE LOW LEVELS. WILL HAVE TO WATCH
THIS HOWEVER...AND AM STILL INDICATING THE POSSIBILITY OF STRONG
TO A FEW SEVERE STORMS NEAR THE COAST AND OFFSHORE IN THE
HAZARDOUS WEATHER OUTLOOK GIVEN THE STRENGTH OF THE MID/UPPER
SYSTEM AND THE STRONG DIFFLUENT FLOW AHEAD OF IT.
FORTUNATELY FOR US...THE EXCESSIVE RAINFALL AMOUNTS THAT FELL IN
TEXAS SHOULD NOT EVEN COME CLOSE TO SOUTHEAST LOUISIANA AND
COASTAL MISSISSIPPI...AND THE MODELS APPEAR TO HAVE A GOOD HANDLE
ON THIS SHOWING THE HIGHER AMOUNTS IN THE 1 TO 2 INCH RANGE.
UPDATED GRIDS AND TEXT PRODUCTS HAVE BEEN SENT.
22/TD
AVIATION...
MID CLOUD DECK WILL PROGRESSIVELY LOWER TO 4 TO 6 KFT BY 08-12Z
AS RAIN FALLS INTO DRIER AIR AND THE SURFACE LOW APPROACHES. RAIN
SHIELD FROM THIS FEATURE WILL GRADUALLY MOVE IN TONIGHT AN INTO
TOMORROW MORNING. CIGS WILL DROP TO MOSTLY MVFR AROUND DAYBREAK
TO MID MORNING...WITH LOWER CUGS POSSIBLE DURING CLUSTERS OF
STRONGER SHOWERS AND ANY THUNDERSTORMS. WINDS WILL GRADUALLY
INCREASE TO AROUND 10-12 KT AND REMAIN MOSTLY NORTHEAST.
PREV DISCUSSION... /ISSUED 725 PM CST FRI NOV 20 2009/
UPDATE...
.SOUNDING DISCUSSION...
NO PROBLEMS WITH THE FLIGHT THIS EVENING. MOISTURE CREEPING BACK
EVER SO SLOWLY WITH A PW UP TO 0.91 INCHES. STILL PLENTY OF DRY
AIR BELOW 700 MILLIBARS BUT A VERY MOIST SOUNDING ABOVE THAT
LAYER. RAINFALL AMOUNTS WILL LIKELY BE ONLY SPRINKLES AND VERY LIGHT
SHOWERS UNTIL THE LOWER LAYERS BECOME MOIST. WINDS ARE LIGHT AND
VARIABLE IN THE LOWEST LEVELS AND FROM THE SOUTHWEST ALOFT.
PREV DISCUSSION... /ISSUED 327 PM CST FRI NOV 20 2009/
SHORT TERM...
ADVANCING HIGH CLOUD DECK A RESULT OF LARGE CONVECTIVE FLARE-UP IN
THE WEST GULF THIS MORNING THAT HAS SINCE MOVED INTO THE MID-GULF
AND WEAKENED DURING THE PAST FEW HOURS. LARGE UPPER LEVEL
DIVERGENCE STRUCTURE WITH ADVANCING LOW PRESSURE TROUGH SWINGING
ACROSS LOWER TEXAS. PRESSURE FALLS NOTED ALONG THE LOWER TEXAS
COAST VICINITY OF BROWNSVILLE FOR WHAT APPEARS TO BE CYCLOGENESIS.
MEANWHILE...HIGH PRESSURE THAT WAS SETTLED OVER THE SOUTEASTERN
U.S. HAS WEAKENED AND RETREATED NORTHWARD...THEREBY SOFTENING THE
GRADIENT MORE THAN PREVIOUSLY EXPECTED FROM EARLIER MODEL RUNS.
GENERALLY FOLLOWING CONTINUITY OF PAST FORECASTS AND SOMEWHAT IN
LINE WITH GFS. BIGGEST UNCERTAINTIES LIE WITH FUTURE TRACK OF
SURFACE LOW...WHICH MAY BE MUCH FARTHER SOUTH THAN ANY MODELS ARE
INDICATING WITH WAKE DEPRESSION HEIGHT FALLS BEHIND CONVECTIVE
COMPLEX IN GULF CARVING A MORE APT TRAJECTORY THAN MODEL INDICATED.
IF SUCH IS THE CASE...THEN MOST OF THE LAND AREAS WILL BE
SUBJECTED TO ISENTROPIC LIFT STRATIFORM AND ELEVATED CONVECTION
FOR A DURATION OF 12 TO 18 HOURS ONSETTING AROUND MIDNIGHT IN THE
WEST AND EXITING THE EAST AROUND SATURDAY LATE AFTERNOON. THE BULK
OF SURFACE BASED CONVECTION SHOULD REMAIN OVER MARINE AREAS BUT
TRENDS WILL HAVE TO BE MONITORED CLOSELY OVERNIGHT AND
PARTICULARLY SATURDAY MORNING. CURRENT AMBIENT CONDITIONS ARE
RATHER DRY AND CONTINENTALLY INFLUENCED SO THE SATURATION PROCESS
FROM TOP-DOWN WILL BE A RATHER SLOW ONE. AFTER LOW PRESSURE
PASSAGE SATURDAY...HIGH PRESSURE SHOULD BUILD INTO THE REGION AND
MAINTAIN A LONG STRETCH OF SEASONABLY COOL TO MILD TEMPERATURES.
LONG TERM...
SEASONABLY COOL TO MILD TEMPERATURES AND GENERALLY RAIN FREE DAYS
ARE IN STORE EXCEPT FOR A BRIEF SHOT AT ISOLATED SHOWERS TUESDAY
WITH THE PASSAGE OF RE-ENFORCING COLD FRONT. MOISTURE DOES APPEAR
TO BE LIMITED WITH THIS SYSTEM. THANKSGIVING TRAVEL SHOULD BE
DEVOID OF ANY WEATHER DELAYS ACROSS THE FORECAST AREA.
MARINE... TRENDS WITH SURFACE PRESSURE GRADIENT WILL HAVE TO BE
MONITORED NEXT 12 HOURS BUT DOES APPEAR TO BE HOLD AROUND THE
15-20 KT RANGE AS LONG AS THE LOW PRESSURE SYSTEM DOES NOT DEEPEN
MUCH FURTHER THAN 1010MB UPON APPROACH. A PERIOD OF HIGHER GUSTS
IN THE 25 TO 30 KT RANGE MAY BE POSSIBLE SATURDAY LATE MORNING BUT
NOT HIGHLY CONFIDENT GIVEN THE WEAKEING GRADIENT. WILL POST
A`SMALL CRAFT EXERCISE CAUTION` HEADLINE VALID AFTER 00Z FOR THE
COASTAL AREAS AT THIS TIME WITH THE POSSIBILITY OF SMALL CRAFT
ADVISORIES IF CONDITIONS EXCEED EXPECTATIONS. AFTER LOW
PASSES...SOME ENHANCED WINDS DUE TO SHORT DURATION COLD AIR
ADVECTION INTO SUNDAY...THEN FLATTENING OUT FOR MUCH OF NEXT WEEK.
FRONTAL PASSAGE ON TUESDAY DOES NOT APPEAR TO HAVE MUCH IMPACT ON
COASTAL AREAS OTHER THAN TO RE-ENFORCE HIGH PRESSURE ALREADY IN
PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 48 58 46 64 / 60 80 40 10
BTR 50 59 47 67 / 80 80 20 10
MSY 55 63 52 66 / 80 80 20 10
GPT 53 63 52 64 / 40 90 40 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
000
FXUS64 KSHV 210323
AFDSHV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
923 PM CST FRI NOV 20 2009
...AN UPDATE TO THE FORECAST WILL BE COMING...
.DISCUSSION...
ISENTROPICALLY-GENERATED AREAS OF LIGHT RAIN CONTINUE TO FALL ACROSS
MUCH OF THE FORECAST AREA THIS EVENING. RAINFALL AMOUNTS HAVE BEEN
ON THE LIGHT SIDE SINCE LATE AFTERNOON...WITH MOST PLACES RECEIVING
LESS THAN A QUARTER INCH.
THE DRIVING FORCE FOR ALL OF THE WEATHER REMAINS AN UPPER-LEVEL
STORM SYSTEM MOVING ACROSS THE TEXAS HILL COUNTRY THIS EVENING. AS
IT CONTINUES PUSHING EASTWARD...LOOK FOR AREAS OF LIGHT RAIN TO
CONTINUE OFF-AND-ON THROUGH THE NIGHT AS SURFACE LOW PRESSURE HEADS
TOWARD SOUTHEAST LOUISIANA.
FOR THE MOST PART...THE ONGOING FORECAST APPEARS TO BE IN GREAT
SHAPE. I HAVE ADJUSTED THE HOURLY TEMPERATURE AND DEWPOINT GRIDS
BASED ON OBSERVATIONAL DATA. THIS HAS RESULTED IN SLIGHTLY WARMER
OVERNIGHT TEMPERATURES /BASED UPON THE LOCAL DIURNAL CURVE/...AND
THE UPDATED NUMBERS ARE LISTED BELOW FOR YOUR PERUSAL. NO
SIGNIFICANT CHANGES WERE OTHERWISE MADE AT THIS TIME.
ISC GRIDS HAVE BEEN SENT AND SHOULD BE POSTED TO THE INTERNET. AN
UPDATED SUITE OF TEXT PRODUCTS WILL BE ISSUED SHORTLY. /21/
&&
.AVIATION...
OFF AND ON LIGHT RAIN SHOWERS OCCURRING AT THE WESTERN TAF SITES AND
AT SHV. HAVE PUT SHRA IN AS PREVAILING WITH TEMPO GROUPS RESERVED
FOR LOWER VSBY AND LOWER CIGS WHICH ARENT CORRESPONDING WITH THE
SHOWERS. VFR CIGS FOR THE MOST PART SHOULD LOWER TO MVFR CIGS AT
MOST OF THE TAF SITES OVERNIGHT...WITH POSSIBLE ISOLATED IFR CIGS AT
LFK THROUGH 21/15Z. AFTER 21/15Z...CIGS WILL GRADUALLY IMPROVE TO
VFR BY 21/21Z AS THE SHORT WAVE MOVES TO THE EAST OF THE FOUR STATE
AREA. VSBYS MAY LOWER TO MVFR IN RAIN AT TIMES THROUGH 21/12Z. EAST
SOUTHEAST WINDS MAY SHIFT TO THE NORTHEAST ON SATURDAY AS A SURFACE
LOW PRESSURE SYSTEM MOVES ALONG THE GULF COAST.
/04/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 52 60 42 68 45 / 60 60 30 10 0
MLU 51 59 43 66 42 / 40 60 40 10 0
DEQ 52 61 41 65 45 / 40 40 30 10 0
TXK 50 60 44 66 44 / 50 50 30 10 0
ELD 49 60 42 65 43 / 30 50 40 10 0
TYR 54 60 45 69 49 / 60 50 20 10 0
GGG 53 60 43 69 47 / 60 50 20 10 0
LFK 51 61 41 70 48 / 70 60 20 10 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
PUBLIC FORECASTER... D. BUTTS
AVIATION FORECASTER... STELLMAN
000
FXUS64 KLCH 210321
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
921 PM CST FRI NOV 20 2009
.DISCUSSION...
LATEST SFC ANALYSIS SHOWS A BROAD AREA OF LOW PRESSURE OFF THE
MIDDLE TX COAST WHILE WATER VAPOR IMAGERY SHOWS SHORTWAVE TROF
CROSSING CNTL TEXAS. WEAK VORTS ROUNDING THE SHORTWAVE EVIDENT IN
CLUSTERS OF RAIN...ONE CURRENTLY MOVING OUT OF S-CNTL LA AND INTO
SERN LA WITH ANOTHER LARGER AREA MOVING ALONG THE UPPER TX COAST
TOWARD SERN TEXAS. YET ANOTHER ROUND OF RAIN SHOWING UP OVER CNTL
TX NEAR THE MAIN SHORTWAVE TROF. SOME CONVECTION NOTED WITHIN THE
RAIN SHIELD OVER THE NWRN GULF IN VICINITY OF THE SFC LOW.
MAIN CHANGE TO THE FORECAST TONIGHT IS TO REMOVE MENTION OF
THUNDER OVER MOST OF THE FORECAST AREA AS CONDITIONS LOOK TOO
STABLE. HOWEVER LEFT MENTION OF ISOLATED THUNDER OVER THE SERN
ZONES AS STORMS OFFSHORE COULD MOVE ASHORE INTO THIS REGION LATER
TONIGHT GIVEN CURRENT AND FORECAST TRAJECTORIES. OTHERWISE GOING
FORECASTS LOOK GOOD WITH RAIN A GOOD BET OVERNIGHT. TEMPS/WINDS
LOOK FINE AS IS AND NO CHANGES PLANNED THERE.
UPDATE OUT SHORTLY.
25
&&
.PREV DISCUSSION... /ISSUED 553 PM CST FRI NOV 20 2009/
AVIATION...
AN AREA OF LIGHT RAIN WAS MOVING EAST ACRS SRN LA...MAINLY
AFFECTING SERN TAF SITES. WILL SEE A BREAK EARLY THIS EVENING WITH
THE NEXT ROUND OF LIGHT RAIN EXPECTED TO MOVE INTO THE NW GULF AND
ACRS SRN AREAS LATE THIS EVENING INTO THE OVERNIGHT HOURS. THIS
RAINFALL IS THE RESULT OF AN UPPER LEVEL TROUGH AND ASSOCIATED SFC
LOW NEAR THE TX COAST THAT WILL LIFT NE ACRS THE AREA TONIGHT INTO
EARLY SATURDAY. EXPECT PERIODS OF MAINLY LIGHT RAIN BEGINNING
AROUND 02Z AT KBPT...WITH RAINFALL PROGRESSING EAST ACRS KLCH AND
INTO KLFT AND KARA FROM 03Z-06Z. VFR CIGS AND VISBYS EXPECTED AT
KAEX. VFR ALSO EXPECTED AT KLFT AND KARA THROUGH LATE
TONIGHT...BECOMING MVFR BETWEEN 10Z-12Z...WHILE GENERALLY MVFR
CONDITIONS TO PREVAIL THROUGHOUT THE PERIOD AT KLCH AND KBPT.
IN ADDITION...AS THE SFC LOW DEVELOPS AND MOVES TOWARD THE AREA
TONIGHT...A TIGHTENING GRADIENT WILL PRODUCE BREEZY NORTHEASTERLY
WINDS WITH POSSIBLE GUSTS BETWEEN 20 AND 25 KTS OVERNIGHT INTO
EARLY SATURDAY MAINLY FOR SRN TAF SITES. 24
PREV DISCUSSION... /ISSUED 435 PM CST FRI NOV 20 2009/
DISCUSSION...RATHER CHALLENGING FORECAST AND HENCE RUNNING A
LITTLE LATE. WAS HOPING FOR BETTER CONTINUITY BETWEEN MODELS...PARTICULARLY
THE EMCWF AND GFS...BUT THIS DID NOT OCCUR. HAVE TRENDED TOWARD
THE GFS SOLUTION WHICH WAS OFFERED SOME SUPPORT BY THE LOCAL WRF
MODEL AS WELL AS HPC. THUS A MORE PROGRESSIVE AND SHORTER-LIVED EVENT
THAN ADVERTISED BY THE EUROPEAN MODEL.
RADAR SHOWING LIGHT TO MODERATE RAINS OVER SOUTH LOUISIANA
ADVANCING EAST. EXPECTING SECONDARY BATCH OF RAINS TO ADVANCE
ACROSS THE AREA OVERNIGHT SO CARRYING CATEGORICAL POPS
SOUTH...LIKELY NORTH. PRIMARILY LOOKING AT OVER-RUNNING RAINS AND
ANY LIGHTNING ACTIVITY TO BE BE MINIMAL AT MOST. RAINS AMOUNTS OF
1 TO 2 INCHES EXPECTED ALONG THE INTERSTATE 10 CORRIDOR SOUTH...AND
LESSER AMOUNTS FURTHER NORTH.
RAINS TAPER OFF SATURDAY WITH SYSTEM ADVANCING EAST. REMAINDER OF
WEEKEND LOOKING DRY AND COOL WITH A NORTHERLY FLOW REMAINING IN
PLACE. NEXT POTENTIAL FROPA AND RAIN-MAKER COMING TUESDAY.
MARINE...LOW PRESSURE DEEPENING AND MOVING ACROSS THE NORTHWEST GULF WILL
BRING STRENGTHENING WINDS AND BUILDING SEAS TONIGHT. WIDESPREAD
RAIN WILL ACCOMPANY THE SYSTEM. WINDS AND RAINS WILL DIMINISH
SATURDAY AS THE SYSTEM EXITS EAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 50 63 46 71 49 / 80 40 10 10 10
KBPT 51 65 46 71 51 / 60 30 10 10 10
KAEX 50 62 43 68 43 / 60 40 10 10 10
KLFT 52 60 47 67 48 / 80 50 10 10 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM CST SATURDAY FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM CAMERON, LA TO HIGH
ISLAND, TX OUT 20 NM...COASTAL WATERS FROM INTRACOASTAL
CITY TO CAMERON, LA OUT 20 NM...COASTAL WATERS FROM LOWER
ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA OUT 20 NM...
WATERS FROM CAMERON, LA TO HIGH ISLAND, TX EXTENDING FROM
20 NM TO 60 NM...WATERS FROM INTRACOASTAL CITY, LA TO
CAMERON, LA EXTENDING FROM 20 NM TO 60 NM...WATERS FROM
LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA EXTENDING
FROM 20 NM TO 60 NM.
GALE WARNING UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING ZONES:
COASTAL WATERS FROM CAMERON, LA TO HIGH ISLAND, TX OUT 20
NM...COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON, LA
OUT 20 NM...COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO
INTRACOASTAL CITY, LA OUT 20 NM...WATERS FROM CAMERON, LA
TO HIGH ISLAND, TX EXTENDING FROM 20 NM TO 60 NM...WATERS
FROM INTRACOASTAL CITY, LA TO CAMERON, LA EXTENDING FROM 20
NM TO 60 NM...WATERS FROM LOWER ATCHAFALAYA RIVER TO
INTRACOASTAL CITY, LA EXTENDING FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING
ZONES: CALCASIEU LAKE...SABINE LAKE...VERMILION BAY.
&&
$$
000
FXUS64 KLIX 210314 CCA
AFDLIX
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE NEW ORLEANS LA
911 PM CST FRI NOV 20 2009
.UPDATE...
THERE IS FINALLY SOME WEATHER TO TALK ABOUT THIS EVENING. A
SERIES OF WELL DEFINED UPPER LEVEL DISTURBANCES ARE MOVING EAST
ACROSS THE WESTERN GULF COAST REGION. THE LEAD SHORTWAVE IS
NEAR THE WESTERN BORDER OF THE FORECAST AREA AND IS PRECEDED BY
PATCHY LIGHT RAIN...MOSTLY FALLING AS SPRINKLES WITH ONLY TRACE
RAINFALL AMOUNTS REPORTED THUS FAR DUE TO THE VERY DRY AIR BELOW
700 MB. THERE IS LIKELY SOME MEASURABLE LIGHT RAIN REACHING THE
GROUND OVER THE COASTAL WATERS FROM SOUTHWEST PASS TO THE LOWER
ATCHAFALAYA RIVER. DEEPER CONVECTION WITH LIGHTNING IS OCCURRING
FARTHER OFFSHORE NEAR THE MIDDLE BUOY /42001/.
THERE IS A BREAK BEHIND THIS FIRST DISTURBANCE WITH NO RAIN
CURRENTLY BEING REPORTED ACROSS MUCH OF SOUTHWEST LOUISIANA.
RADAR SHOWS ONLY ISOLATED SHOWER ACTIVITY OFF THE COAST OF
SOUTHWEST LOUISIANA.
FARTHER WEST...THE MAIN...STRONGER SHORTWAVE TROUGH AND DEVELOPING
UPPER LOW IS OVER CENTRAL TEXAS AND PRECEDED BY ANOTHER
DISTURBANCE AND THE MAIN SURFACE LOW NEAR THE CENTRAL TEXAS COAST.
THUNDERSTORMS ASSOCIATED WITH THIS DISTURBANCE EXTEND FARTHER
NORTH...BUT ARE MOSTLY ELEVATED. THIS SYSTEM PRODUCED OVER 10
INCHES OF RAIN ALONG PORTIONS OF THE CENTRAL TEXAS COAST LAST
NIGHT AND THIS MORNING.
THE COMPLICATING PART OF THIS UPDATE IS HOW TO DESCRIBE THE RAIN
TRENDS TONIGHT WITH THE AFOREMENTIONED FEATURES IN THE PREVIOUS
PARAGRAPHS. THE BEST WAY TO DESCRIBE THE FORECAST IS A FEW
SPRINKLES WITH A SLIGHT CHANCE OF BARELY MEASURABLE /.01 INCHES/
EARLY ON...TRENDING TOWARDS MORE STEADY RAIN IN SOME SOUTHERN
AREAS...BUT THEN ONLY A SLIGHT CHANCE OF SHOWERS FOR SEVERAL
HOURS BETWEEN SHORTWAVES...FOLLOWED BY MORE WIDESPREAD RAIN AND
SHOWERS SPREADING FROM WEST TO EAST AFTER MIDNIGHT AS ISENTROPIC
LIFT INCREASES AHEAD OF THE SECOND DISTURBANCE AND APPROACHING
SURFACE LOW. HAVING SAID THAT...HAVE PLACED WORDING OF SPRINKLES
EARLY ON IN THE ZONE FORECAST THEN TRENDED TOWARDS THE MORE
NUMEROUS TO WIDESPREAD SHOWERS IN THE WESTERN AND CENTRAL ZONES
LATER ON TONIGHT. A NOTE ABOUT THE MODELS...THE 18Z GFS WILL
VERIFY HORRIBLY WITH ITS HEAVY RAIN THAT IS SHOWS THIS EVENING
OVER SOUTHERN PORTIONS OF SOUTHEAST LOUISIANA.
LOOKING AT WINDS...THEY HAVE BEEN TRENDING A BIT LIGHTER THAN
FORECAST...SO DO NOT SEE THE REASON TO RAISE THE SMALL CRAFT
ADVISORY /SCA/ FLAGS JUST YET. THE NEXT SHIFT WILL HAVE TO
MONITOR NEW DATA AND DECIDE IF A SCA IS NEEDED ON SATURDAY.
ON SATURDAY...ALSO MADE SOME ADJUSTMENTS TO INCLUDE ISOLATED TO
SCATTERED THUNDERSTORMS OVER MAINLY COASTAL LAND AREAS AND SOME
INLAND PARISHES AND COUNTIES TO BE CONSISTENT WITH SPC. MODEL
SOUNDINGS SHOW VERY ELEVATED INSTABILITY LIFTING FROM 750-700
EARLY MORNING LOWERING TO 850-800 MB IN THE AFTERNOON BEFORE DRIER
AIR DIMINISHES THE POPS LATE IN THE AFTERNOON. IT APPEARS ANY
TRUE SURFACE BASED INSTABILITY WILL REMAIN WELL OFFSHORE EVEN IF
THE SURFACE LOW TRACKS SLIGHTLY INLAND...OWING TO THE LINGERING
EFFECTS OF CURRENT DRY AIR IN THE LOW LEVELS. WILL HAVE TO WATCH
THIS HOWEVER...AND AM STILL INDICATING THE POSSIBILITY OF STRONG
TO A FEW SEVERE STORMS NEAR THE COAST AND OFFSHORE IN THE
HAZARDOUS WEATHER OUTLOOK GIVEN THE STRENGTH OF THE MID/UPPER
SYSTEM AND THE STRONG DIFFLUENT FLOW AHEAD OF IT.
FORTUNATELY FOR US...THE EXCESSIVE RAINFALL AMOUNTS THAT FELL IN
TEXAS SHOULD NOT EVEN COME CLOSE TO SOUTHEAST LOUISIANA AND
COASTAL MISSISSIPPI...AND THE MODELS APPEAR TO HAVE A GOOD HANDLE
ON THIS SHOWING THE HIGHER AMOUNTS IN THE 1 TO 2 INCH RANGE.
UPDATED GRIDS AND TEXT PRODUCTS HAVE BEEN SENT.
22/TD
&&
.AVIATION...
MID CLOUD DECK WILL PROGRESSIVELY LOWER TO 4 TO 6 KFT BY 08-12Z
AS RAIN FALLS INTO DRIER AIR AND THE SURFACE LOW APPROACHES. RAIN
SHIELD FROM THIS FEATURE WILL GRADUALLY MOVE IN TONIGHT AN INTO
TOMORROW MORNING. CIGS WILL DROP TO MOSTLY MVFR AROUND DAYBREAK
TO MID MORNING...WITH LOWER CUGS POSSIBLE DURING CLUSTERS OF
STRONGER SHOWERS AND ANY THUNDERSTORMS. WINDS WILL GRADUALLY
INCREASE TO AROUND 10-12 KT AND REMAIN MOSTLY NORTHEAST.
&&
.PREV DISCUSSION... /ISSUED 725 PM CST FRI NOV 20 2009/
UPDATE...
..SOUNDING DISCUSSION...
NO PROBLEMS WITH THE FLIGHT THIS EVENING. MOISTURE CREEPING BACK
EVER SO SLOWLY WITH A PW UP TO 0.91 INCHES. STILL PLENTY OF DRY
AIR BELOW 700 MILLIBARS BUT A VERY MOIST SOUNDING ABOVE THAT
LAYER. RAINFALL AMOUNTS WILL LIKELY BE ONLY SPRINKLES AND VERY LIGHT
SHOWERS UNTIL THE LOWER LAYERS BECOME MOIST. WINDS ARE LIGHT AND
VARIABLE IN THE LOWEST LEVELS AND FROM THE SOUTHWEST ALOFT.
PREV DISCUSSION... /ISSUED 327 PM CST FRI NOV 20 2009/
SHORT TERM...
ADVANCING HIGH CLOUD DECK A RESULT OF LARGE CONVECTIVE FLARE-UP IN
THE WEST GULF THIS MORNING THAT HAS SINCE MOVED INTO THE MID-GULF
AND WEAKENED DURING THE PAST FEW HOURS. LARGE UPPER LEVEL
DIVERGENCE STRUCTURE WITH ADVANCING LOW PRESSURE TROUGH SWINGING
ACROSS LOWER TEXAS. PRESSURE FALLS NOTED ALONG THE LOWER TEXAS
COAST VICINITY OF BROWNSVILLE FOR WHAT APPEARS TO BE CYCLOGENESIS.
MEANWHILE...HIGH PRESSURE THAT WAS SETTLED OVER THE SOUTEASTERN
U.S. HAS WEAKENED AND RETREATED NORTHWARD...THEREBY SOFTENING THE
GRADIENT MORE THAN PREVIOUSLY EXPECTED FROM EARLIER MODEL RUNS.
GENERALLY FOLLOWING CONTINUITY OF PAST FORECASTS AND SOMEWHAT IN
LINE WITH GFS. BIGGEST UNCERTAINTIES LIE WITH FUTURE TRACK OF
SURFACE LOW...WHICH MAY BE MUCH FARTHER SOUTH THAN ANY MODELS ARE
INDICATING WITH WAKE DEPRESSION HEIGHT FALLS BEHIND CONVECTIVE
COMPLEX IN GULF CARVING A MORE APT TRAJECTORY THAN MODEL INDICATED.
IF SUCH IS THE CASE...THEN MOST OF THE LAND AREAS WILL BE
SUBJECTED TO ISENTROPIC LIFT STRATIFORM AND ELEVATED CONVECTION
FOR A DURATION OF 12 TO 18 HOURS ONSETTING AROUND MIDNIGHT IN THE
WEST AND EXITING THE EAST AROUND SATURDAY LATE AFTERNOON. THE BULK
OF SURFACE BASED CONVECTION SHOULD REMAIN OVER MARINE AREAS BUT
TRENDS WILL HAVE TO BE MONITORED CLOSELY OVERNIGHT AND
PARTICULARLY SATURDAY MORNING. CURRENT AMBIENT CONDITIONS ARE
RATHER DRY AND CONTINENTALLY INFLUENCED SO THE SATURATION PROCESS
FROM TOP-DOWN WILL BE A RATHER SLOW ONE. AFTER LOW PRESSURE
PASSAGE SATURDAY...HIGH PRESSURE SHOULD BUILD INTO THE REGION AND
MAINTAIN A LONG STRETCH OF SEASONABLY COOL TO MILD TEMPERATURES.
LONG TERM...
SEASONABLY COOL TO MILD TEMPERATURES AND GENERALLY RAIN FREE DAYS
ARE IN STORE EXCEPT FOR A BRIEF SHOT AT ISOLATED SHOWERS TUESDAY
WITH THE PASSAGE OF RE-ENFORCING COLD FRONT. MOISTURE DOES APPEAR
TO BE LIMITED WITH THIS SYSTEM. THANKSGIVING TRAVEL SHOULD BE
DEVOID OF ANY WEATHER DELAYS ACROSS THE FORECAST AREA.
MARINE... TRENDS WITH SURFACE PRESSURE GRADIENT WILL HAVE TO BE
MONITORED NEXT 12 HOURS BUT DOES APPEAR TO BE HOLD AROUND THE
15-20 KT RANGE AS LONG AS THE LOW PRESSURE SYSTEM DOES NOT DEEPEN
MUCH FURTHER THAN 1010MB UPON APPROACH. A PERIOD OF HIGHER GUSTS
IN THE 25 TO 30 KT RANGE MAY BE POSSIBLE SATURDAY LATE MORNING BUT
NOT HIGHLY CONFIDENT GIVEN THE WEAKEING GRADIENT. WILL POST
A`SMALL CRAFT EXERCISE CAUTION` HEADLINE VALID AFTER 00Z FOR THE
COASTAL AREAS AT THIS TIME WITH THE POSSIBILITY OF SMALL CRAFT
ADVISORIES IF CONDITIONS EXCEED EXPECTATIONS. AFTER LOW
PASSES...SOME ENHANCED WINDS DUE TO SHORT DURATION COLD AIR
ADVECTION INTO SUNDAY...THEN FLATTENING OUT FOR MUCH OF NEXT WEEK.
FRONTAL PASSAGE ON TUESDAY DOES NOT APPEAR TO HAVE MUCH IMPACT ON
COASTAL AREAS OTHER THAN TO RE-ENFORCE HIGH PRESSURE ALREADY IN
PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 48 58 46 64 / 60 80 40 10
BTR 50 59 47 67 / 80 80 20 10
MSY 55 63 52 66 / 80 80 20 10
GPT 53 63 52 64 / 40 90 40 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
000
FXUS64 KLIX 210308 AAA
AFDLIX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NEW ORLEANS LA
908 PM CST FRI NOV 20 2009
.UPDATE...
THERE IS FINALLY SOME WEATHER TO TALK ABOUT THIS EVENING. A
SERIES OF WELL DEFINED UPPER LEVEL DISTURBANCES ARE MOVING EAST
ACROSS THE WESTERN GULF COAST REGION. THE LEAD SHORTWAVE IS
NEAR THE WESTERN BORDER OF THE FORECAST AREA AND IS PRECEDED BY
PATCHY LIGHT RAIN...MOSTLY FALLING AS SPRINKLES WITH ONLY TRACE
RAINFALL AMOUNTS REPORTED THUS FAR DUE TO THE VERY DRY AIR BELOW
700 MB. THERE IS LIKELY SOME MEASURABLE LIGHT RAIN REACHING THE
GROUND OVER THE COASTAL WATERS FROM SOUTHWEST PASS TO THE LOWER
ATCHAFALAYA RIVER. DEEPER CONVECTION WITH LIGHTNING IS OCCURRING
FARTHER OFFSHORE NEAR THE MIDDLE BUOY /42001/.
THERE IS A BREAK BEHIND THIS FIRST DISTURBANCE WITH NO RAIN
CURRENTLY BEING REPORTED ACROSS MUCH OF SOUTHWEST LOUISIANA.
RADAR SHOWS ONLY ISOLATED SHOWER ACTIVITY OFF THE COAST OF
SOUTHWEST LOUISIANA.
FARTHER WEST...THE MAIN...STRONGER SHORTWAVE TROUGH AND DEVELOPING
UPPER LOW IS OVER CENTRAL TEXAS AND PRECEDED BY ANOTHER
DISTURBANCE AND THE MAIN SURFACE LOW NEAR THE CENTRAL TEXAS COAST.
THUNDERSTORMS ASSOCIATED WITH THIS DISTURBANCE EXTEND FARTHER
NORTH...BUT ARE MOSTLY ELEVATED. THIS SYSTEM PRODUCED OVER 10
INCHES OF RAIN ALONG PORTIONS OF THE CENTRAL TEXAS COAST LAST
NIGHT AND THIS MORNING.
THE COMPLICATING PART OF THIS UPDATE IS HOW TO DESCRIBE THE RAIN
TRENDS TONIGHT WITH THE AFOREMENTIONED FEATURES IN THE PREVIOUS
PARAGRAPHS. THE BEST WAY TO DESCRIBE THE FORECAST IS A FEW
SPRINKLES WITH A SLIGHT CHANCE OF BARELY MEASURABLE /.01 INCHES/
EARLY ON...TRENDING TOWARDS MORE STEADY RAIN IN SOME SOUTHERN
AREAS...BUT THEN ONLY A SLIGHT CHANCE OF SHOWERS FOR SEVERAL
HOURS BETWEEN SHORTWAVES...FOLLOWED BY MORE WIDESPREAD RAIN AND
SHOWERS SPREADING FROM WEST TO EAST AFTER MIDNIGHT AS ISENTROPIC
LIFT INCREASES AHEAD OF THE SECOND DISTURBANCE AND APPROACHING
SURFACE LOW. HAVING SAID THAT...HAVE PLACED WORDING OF SPRINKLES
EARLY ON IN THE ZONE FORECAST THEN TRENDED TOWARDS THE MORE
NUMEROUS TO WIDESPREAD SHOWERS IN THE WESTERN AND CENTRAL ZONES
LATER ON TONIGHT. A NOTE ABOUT THE MODELS...THE 18Z GFS WILL
VERIFY HORRIBLY WITH ITS HEAVY RAIN THAT IS SHOWS THIS EVENING
OVER SOUTHERN PORTIONS OF SOUTHEAST LOUISIANA.
LOOKING AT WINDS...THEY HAVE BEEN TRENDING A BIT LIGHTER THAN
FORECAST...SO DO NOT SEE THE REASON TO RAISE THE SMALL CRAFT
ADVISORY /SCA/ FLAGS JUST YET. THE NEXT SHIFT WILL HAVE TO
MONITOR NEW DATA AND DECIDE IF A SCA IS NEEDED ON SATURDAY.
ON SATURDAY...ALSO MADE SOME ADJUSTMENTS TO INCLUDE ISOLATED TO
SCATTERED THUNDERSTORMS OVER MAINLY COASTAL LAND AREAS AND SOME
INLAND PARISHES AND COUNTIES TO BE CONSISTENT WITH SPC. MODEL
SOUNDINGS SHOW VERY ELEVATED INSTABILITY LIFTING FROM 750-700
EARLY MORNING LOWERING TO 850-800 MB IN THE AFTERNOON BEFORE DRIER
AIR DIMINISHES THE POPS LATE IN THE AFTERNOON. IT APPEARS ANY
TRUE SURFACE BASED INSTABILITY WILL REMAIN WELL OFFSHORE EVEN IF
THE SURFACE LOW TRACKS SLIGHTLY INLAND...OWING TO THE LINGERING
EFFECTS OF CURRENT DRY AIR IN THE LEVELS. WILL HAVE TO WATCH THIS
HOWEVER...AND AM STILL INDICATING THE POSSIBILITY OF STRONG TO A
FEW SEVERE STORMS NEAR THE COAST AND OFFSHORE IN THE HAZARDOUS
WEATHER OUTLOOK GIVEN THE STRENGTH OF THE MID/UPPER SYSTEM AND THE
STRONG DIFFLUENT FLOW AHEAD OF IT.
FORTUNATELY FOR US...THE EXCESSIVE RAINFALL AMOUNTS THAT FELL IN
TEXAS SHOULD NOT EVEN COME CLOSE TO SOUTHEAST LOUISIANA AND
COASTAL MISSISSIPPI...AND THE MODELS APPEAR TO HAVE A GOOD HANDLE
ON THIS SHOWING THE HIGHER AMOUNTS IN THE 1 TO 2 INCH RANGE.
UPDATED GRIDS AND TEXT PRODUCTS HAVE BEEN SENT.
22/TD
&&
.AVIATION...
MID CLOUD DECK WILL PROGRESSIVELY LOWER TO 4 TO 6 KFT BY 08-12Z
AS RAIN FALLS INTO DRIER AIR AND THE SURFACE LOW APPROACHES. RAIN
SHIELD FROM THIS FEATURE WILL GRADUALLY MOVE IN TONIGHT AN INTO
TOMORROW MORNING. CIGS WILL DROP TO MOSTLY MVFR AROUND DAYBREAK
TO MID MORNING...WITH LOWER CUGS POSSIBLE DURING CLUSTERS OF
STRONGER SHOWERS AND ANY THUNDERSTORMS. WINDS WILL GRADUALLY
INCREASE TO AROUND 10-12 KT AND REMAIN MOSTLY NORTHEAST.
&&
.PREV DISCUSSION... /ISSUED 725 PM CST FRI NOV 20 2009/
UPDATE...
..SOUNDING DISCUSSION...
NO PROBLEMS WITH THE FLIGHT THIS EVENING. MOISTURE CREEPING BACK
EVER SO SLOWLY WITH A PW UP TO 0.91 INCHES. STILL PLENTY OF DRY
AIR BELOW 700 MILLIBARS BUT A VERY MOIST SOUNDING ABOVE THAT
LAYER. RAINFALL AMOUNTS WILL LIKELY BE ONLY SPRINKLES AND VERY LIGHT
SHOWERS UNTIL THE LOWER LAYERS BECOME MOIST. WINDS ARE LIGHT AND
VARIABLE IN THE LOWEST LEVELS AND FROM THE SOUTHWEST ALOFT.
PREV DISCUSSION... /ISSUED 327 PM CST FRI NOV 20 2009/
SHORT TERM...
ADVANCING HIGH CLOUD DECK A RESULT OF LARGE CONVECTIVE FLARE-UP IN
THE WEST GULF THIS MORNING THAT HAS SINCE MOVED INTO THE MID-GULF
AND WEAKENED DURING THE PAST FEW HOURS. LARGE UPPER LEVEL
DIVERGENCE STRUCTURE WITH ADVANCING LOW PRESSURE TROUGH SWINGING
ACROSS LOWER TEXAS. PRESSURE FALLS NOTED ALONG THE LOWER TEXAS
COAST VICINITY OF BROWNSVILLE FOR WHAT APPEARS TO BE CYCLOGENESIS.
MEANWHILE...HIGH PRESSURE THAT WAS SETTLED OVER THE SOUTEASTERN
U.S. HAS WEAKENED AND RETREATED NORTHWARD...THEREBY SOFTENING THE
GRADIENT MORE THAN PREVIOUSLY EXPECTED FROM EARLIER MODEL RUNS.
GENERALLY FOLLOWING CONTINUITY OF PAST FORECASTS AND SOMEWHAT IN
LINE WITH GFS. BIGGEST UNCERTAINTIES LIE WITH FUTURE TRACK OF
SURFACE LOW...WHICH MAY BE MUCH FARTHER SOUTH THAN ANY MODELS ARE
INDICATING WITH WAKE DEPRESSION HEIGHT FALLS BEHIND CONVECTIVE
COMPLEX IN GULF CARVING A MORE APT TRAJECTORY THAN MODEL INDICATED.
IF SUCH IS THE CASE...THEN MOST OF THE LAND AREAS WILL BE
SUBJECTED TO ISENTROPIC LIFT STRATIFORM AND ELEVATED CONVECTION
FOR A DURATION OF 12 TO 18 HOURS ONSETTING AROUND MIDNIGHT IN THE
WEST AND EXITING THE EAST AROUND SATURDAY LATE AFTERNOON. THE BULK
OF SURFACE BASED CONVECTION SHOULD REMAIN OVER MARINE AREAS BUT
TRENDS WILL HAVE TO BE MONITORED CLOSELY OVERNIGHT AND
PARTICULARLY SATURDAY MORNING. CURRENT AMBIENT CONDITIONS ARE
RATHER DRY AND CONTINENTALLY INFLUENCED SO THE SATURATION PROCESS
FROM TOP-DOWN WILL BE A RATHER SLOW ONE. AFTER LOW PRESSURE
PASSAGE SATURDAY...HIGH PRESSURE SHOULD BUILD INTO THE REGION AND
MAINTAIN A LONG STRETCH OF SEASONABLY COOL TO MILD TEMPERATURES.
LONG TERM...
SEASONABLY COOL TO MILD TEMPERATURES AND GENERALLY RAIN FREE DAYS
ARE IN STORE EXCEPT FOR A BRIEF SHOT AT ISOLATED SHOWERS TUESDAY
WITH THE PASSAGE OF RE-ENFORCING COLD FRONT. MOISTURE DOES APPEAR
TO BE LIMITED WITH THIS SYSTEM. THANKSGIVING TRAVEL SHOULD BE
DEVOID OF ANY WEATHER DELAYS ACROSS THE FORECAST AREA.
MARINE... TRENDS WITH SURFACE PRESSURE GRADIENT WILL HAVE TO BE
MONITORED NEXT 12 HOURS BUT DOES APPEAR TO BE HOLD AROUND THE
15-20 KT RANGE AS LONG AS THE LOW PRESSURE SYSTEM DOES NOT DEEPEN
MUCH FURTHER THAN 1010MB UPON APPROACH. A PERIOD OF HIGHER GUSTS
IN THE 25 TO 30 KT RANGE MAY BE POSSIBLE SATURDAY LATE MORNING BUT
NOT HIGHLY CONFIDENT GIVEN THE WEAKEING GRADIENT. WILL POST
A`SMALL CRAFT EXERCISE CAUTION` HEADLINE VALID AFTER 00Z FOR THE
COASTAL AREAS AT THIS TIME WITH THE POSSIBILITY OF SMALL CRAFT
ADVISORIES IF CONDITIONS EXCEED EXPECTATIONS. AFTER LOW
PASSES...SOME ENHANCED WINDS DUE TO SHORT DURATION COLD AIR
ADVECTION INTO SUNDAY...THEN FLATTENING OUT FOR MUCH OF NEXT WEEK.
FRONTAL PASSAGE ON TUESDAY DOES NOT APPEAR TO HAVE MUCH IMPACT ON
COASTAL AREAS OTHER THAN TO RE-ENFORCE HIGH PRESSURE ALREADY IN
PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 48 58 46 64 / 60 80 40 10
BTR 50 59 47 67 / 80 80 20 10
MSY 55 63 52 66 / 80 80 20 10
GPT 53 63 52 64 / 40 90 40 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
000
FXUS64 KLIX 210125
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
725 PM CST FRI NOV 20 2009
.UPDATE...
...SOUNDING DISCUSSION...
NO PROBLEMS WITH THE FLIGHT THIS EVENING. MOISTURE CREEPING BACK
EVER SO SLOWLY WITH A PW UP TO 0.91 INCHES. STILL PLENTY OF DRY
AIR BELOW 700 MILLIBARS BUT A VERY MOIST SOUNDING ABOVE THAT
LAYER. RAINFALL AMOUNTS WILL LIKELY BE ONLY SPRINKLES AND VERY LIGHT
SHOWERS UNTIL THE LOWER LAYERS BECOME MOIST. WINDS ARE LIGHT AND
VARIABLE IN THE LOWEST LEVELS AND FROM THE SOUTHWEST ALOFT.
&&
.PREV DISCUSSION... /ISSUED 327 PM CST FRI NOV 20 2009/
SHORT TERM...
ADVANCING HIGH CLOUD DECK A RESULT OF LARGE CONVECTIVE FLARE-UP IN
THE WEST GULF THIS MORNING THAT HAS SINCE MOVED INTO THE MID-GULF
AND WEAKENED DURING THE PAST FEW HOURS. LARGE UPPER LEVEL
DIVERGENCE STRUCTURE WITH ADVANCING LOW PRESSURE TROUGH SWINGING
ACROSS LOWER TEXAS. PRESSURE FALLS NOTED ALONG THE LOWER TEXAS
COAST VICINITY OF BROWNSVILLE FOR WHAT APPEARS TO BE CYCLOGENESIS.
MEANWHILE...HIGH PRESSURE THAT WAS SETTLED OVER THE SOUTEASTERN
U.S. HAS WEAKENED AND RETREATED NORTHWARD...THEREBY SOFTENING THE
GRADIENT MORE THAN PREVIOUSLY EXPECTED FROM EARLIER MODEL RUNS.
GENERALLY FOLLOWING CONTINUITY OF PAST FORECASTS AND SOMEWHAT IN
LINE WITH GFS. BIGGEST UNCERTAINTIES LIE WITH FUTURE TRACK OF
SURFACE LOW...WHICH MAY BE MUCH FARTHER SOUTH THAN ANY MODELS ARE
INDICATING WITH WAKE DEPRESSION HEIGHT FALLS BEHIND CONVECTIVE
COMPLEX IN GULF CARVING A MORE APT TRAJECTORY THAN MODEL INDICATED.
IF SUCH IS THE CASE...THEN MOST OF THE LAND AREAS WILL BE
SUBJECTED TO ISENTROPIC LIFT STRATIFORM AND ELEVATED CONVECTION
FOR A DURATION OF 12 TO 18 HOURS ONSETTING AROUND MIDNIGHT IN THE
WEST AND EXITING THE EAST AROUND SATURDAY LATE AFTERNOON. THE BULK
OF SURFACE BASED CONVECTION SHOULD REMAIN OVER MARINE AREAS BUT
TRENDS WILL HAVE TO BE MONITORED CLOSELY OVERNIGHT AND
PARTICULARLY SATURDAY MORNING. CURRENT AMBIENT CONDITIONS ARE
RATHER DRY AND CONTINENTALLY INFLUENCED SO THE SATURATION PROCESS
FROM TOP-DOWN WILL BE A RATHER SLOW ONE. AFTER LOW PRESSURE
PASSAGE SATURDAY...HIGH PRESSURE SHOULD BUILD INTO THE REGION AND
MAINTAIN A LONG STRETCH OF SEASONABLY COOL TO MILD TEMPERATURES.
LONG TERM...
SEASONABLY COOL TO MILD TEMPERATURES AND GENERALLY RAIN FREE DAYS
ARE IN STORE EXCEPT FOR A BRIEF SHOT AT ISOLATED SHOWERS TUESDAY
WITH THE PASSAGE OF RE-ENFORCING COLD FRONT. MOISTURE DOES APPEAR
TO BE LIMITED WITH THIS SYSTEM. THANKSGIVING TRAVEL SHOULD BE
DEVOID OF ANY WEATHER DELAYS ACROSS THE FORECAST AREA.
AVIATION...
VFR CONDITIONS SHOULD PERSIST AT TERMINALS THRU 00Z. SFC LOW OVER
THE NWRN GULF WILL CONTINUE ON AN ENE TRACK TOWARDS THE AREA. HIGH
LEVEL CLOUDS WILL PROGRESSIVELY INCREASE OVER THE NEXT FEW HOURS.
RAIN SHIELD FROM THIS FEATURE REMAINS SW OF THE AREA BUT WILL
GRADUALLY MOVE IN TONIGHT AN INTO TOMORROW MORNING. CIGS WILL DROP
TO MOSTLY MVFR BY DAYBREAK BUT POSSIBLY LOWER WITH CLUSTERS OF
STRONGER SHOWERS. WINDS WILL SLOWLY TRANSITION FROM ENE TO NNE BY
THE END OF THE PERIOD. MEFFER
MARINE...
TRENDS WITH SURFACE PRESSURE GRADIENT WILL HAVE TO BE MONITORED
NEXT 12 HOURS BUT DOES APPEAR TO BE HOLD AROUND THE 15-20 KT RANGE
AS LONG AS THE LOW PRESSURE SYSTEM DOES NOT DEEPEN MUCH FURTHER
THAN 1010MB UPON APPROACH. A PERIOD OF HIGHER GUSTS IN THE 25 TO
30 KT RANGE MAY BE POSSIBLE SATURDAY LATE MORNING BUT NOT HIGHLY
CONFIDENT GIVEN THE WEAKEING GRADIENT. WILL POST A`SMALL CRAFT
EXERCISE CAUTION` HEADLINE VALID AFTER 00Z FOR THE COASTAL AREAS
AT THIS TIME WITH THE POSSIBILITY OF SMALL CRAFT ADVISORIES IF
CONDITIONS EXCEED EXPECTATIONS. AFTER LOW PASSES...SOME ENHANCED
WINDS DUE TO SHORT DURATION COLD AIR ADVECTION INTO SUNDAY...THEN
FLATTENING OUT FOR MUCH OF NEXT WEEK. FRONTAL PASSAGE ON TUESDAY
DOES NOT APPEAR TO HAVE MUCH IMPACT ON COASTAL AREAS OTHER THAN TO
RE-ENFORCE HIGH PRESSURE ALREADY IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 48 58 46 64 / 60 80 40 10
BTR 50 59 47 67 / 80 80 20 10
MSY 55 63 52 66 / 80 80 20 10
GPT 53 63 52 64 / 40 90 40 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
000
FXUS64 KLCH 202353
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
553 PM CST FRI NOV 20 2009
.AVIATION...
AN AREA OF LIGHT RAIN WAS MOVING EAST ACRS SRN LA...MAINLY
AFFECTING SERN TAF SITES. WILL SEE A BREAK EARLY THIS EVENING WITH
THE NEXT ROUND OF LIGHT RAIN EXPECTED TO MOVE INTO THE NW GULF AND
ACRS SRN AREAS LATE THIS EVENING INTO THE OVERNIGHT HOURS. THIS
RAINFALL IS THE RESULT OF AN UPPER LEVEL TROUGH AND ASSOCIATED SFC
LOW NEAR THE TX COAST THAT WILL LIFT NE ACRS THE AREA TONIGHT INTO
EARLY SATURDAY. EXPECT PERIODS OF MAINLY LIGHT RAIN BEGINNING
AROUND 02Z AT KBPT...WITH RAINFALL PROGRESSING EAST ACRS KLCH AND
INTO KLFT AND KARA FROM 03Z-06Z. VFR CIGS AND VISBYS EXPECTED AT
KAEX. VFR ALSO EXPECTED AT KLFT AND KARA THROUGH LATE
TONIGHT...BECOMING MVFR BETWEEN 10Z-12Z...WHILE GENERALLY MVFR
CONDITIONS TO PREVAIL THROUGHOUT THE PERIOD AT KLCH AND KBPT.
IN ADDITION...AS THE SFC LOW DEVELOPS AND MOVES TOWARD THE AREA
TONIGHT...A TIGHTENING GRADIENT WILL PRODUCE BREEZY NORTHEASTERLY
WINDS WITH POSSIBLE GUSTS BETWEEN 20 AND 25 KTS OVERNIGHT INTO
EARLY SATURDAY MAINLY FOR SRN TAF SITES. 24
&&
.PREV DISCUSSION... /ISSUED 435 PM CST FRI NOV 20 2009/
DISCUSSION...RATHER CHALLENGING FORECAST AND HENCE RUNNING A
LITTLE LATE. WAS HOPING FOR BETTER CONTINUITY BETWEEN MODELS...PARTICULARLY
THE EMCWF AND GFS...BUT THIS DID NOT OCCUR. HAVE TRENDED TOWARD
THE GFS SOLUTION WHICH WAS OFFERED SOME SUPPORT BY THE LOCAL WRF
MODEL AS WELL AS HPC. THUS A MORE PROGRESSIVE AND SHORTER-LIVED EVENT
THAN ADVERTISED BY THE EUROPEAN MODEL.
RADAR SHOWING LIGHT TO MODERATE RAINS OVER SOUTH LOUISIANA
ADVANCING EAST. EXPECTING SECONDARY BATCH OF RAINS TO ADVANCE
ACROSS THE AREA OVERNIGHT SO CARRYING CATEGORICAL POPS
SOUTH...LIKELY NORTH. PRIMARILY LOOKING AT OVER-RUNNING RAINS AND
ANY LIGHTNING ACTIVITY TO BE BE MINIMAL AT MOST. RAINS AMOUNTS OF
1 TO 2 INCHES EXPECTED ALONG THE INTERSTATE 10 CORRIDOR SOUTH...AND
LESSER AMOUNTS FURTHER NORTH.
RAINS TAPER OFF SATURDAY WITH SYSTEM ADVANCING EAST. REMAINDER OF
WEEKEND LOOKING DRY AND COOL WITH A NORTHERLY FLOW REMAINING IN
PLACE. NEXT POTENTIAL FROPA AND RAIN-MAKER COMING TUESDAY.
MARINE...LOW PRESSURE DEEPENING AND MOVING ACROSS THE NORTHWEST GULF WILL
BRING STRENGTHENING WINDS AND BUILDING SEAS TONIGHT. WIDESPREAD
RAIN WILL ACCOMPANY THE SYSTEM. WINDS AND RAINS WILL DIMINISH
SATURDAY AS THE SYSTEM EXITS EAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 50 63 46 71 / 80 40 10 10
KBPT 51 65 46 71 / 60 30 10 10
KAEX 50 62 43 68 / 60 40 10 10
KLFT 52 60 47 67 / 80 50 10 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM CST SATURDAY FOR COASTAL
WATERS FROM CAMERON, LA TO HIGH ISLAND, TX OUT 20 NM-
COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON, LA OUT 20
NM-COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO
INTRACOASTAL CITY, LA OUT 20 NM-WATERS FROM CAMERON, LA TO
HIGH ISLAND, TX EXTENDING FROM 20 NM TO 60 NM-WATERS FROM
INTRACOASTAL CITY, LA TO CAMERON, LA EXTENDING FROM 20 NM
TO 60 NM-WATERS FROM LOWER ATCHAFALAYA RIVER TO
INTRACOASTAL CITY, LA EXTENDING FROM 20 NM TO 60 NM.
GALE WARNING UNTIL 6 AM CST SATURDAY FOR COASTAL WATERS FROM
LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA OUT 20 NM-
WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY,
LA EXTENDING FROM 20 NM TO 60 NM.
GALE WARNING UNTIL 6 AM CST SATURDAY FOR COASTAL WATERS FROM
CAMERON, LA TO HIGH ISLAND, TX OUT 20 NM-COASTAL WATERS
FROM INTRACOASTAL CITY TO CAMERON, LA OUT 20 NM-WATERS FROM
CAMERON, LA TO HIGH ISLAND, TX EXTENDING FROM 20 NM TO 60
NM-WATERS FROM INTRACOASTAL CITY, LA TO CAMERON, LA
EXTENDING FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 6 AM CST SATURDAY FOR CALCASIEU LAKE-
SABINE LAKE-VERMILION BAY.
&&
$$
PUBLIC/MARINE...23
AVIATION...24
000
FXUS64 KLCH 202235
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
435 PM CST FRI NOV 20 2009
.DISCUSSION...RATHER CHALLENGING FORECAST AND HENCE RUNNING A
LITTLE LATE. WAS HOPING FOR BETTER CONTINUITY BETWEEN MODELS...PARTICULARLY
THE EMCWF AND GFS...BUT THIS DID NOT OCCUR. HAVE TRENDED TOWARD
THE GFS SOLUTION WHICH WAS OFFERED SOME SUPPORT BY THE LOCAL WRF
MODEL AS WELL AS HPC. THUS A MORE PROGRESSIVE AND SHORTER-LIVED EVENT
THAN ADVERTISED BY THE EUROPEAN MODEL.
RADAR SHOWING LIGHT TO MODERATE RAINS OVER SOUTH LOUISIANA
ADVANCING EAST. EXPECTING SECONDARY BATCH OF RAINS TO ADVANCE
ACROSS THE AREA OVERNIGHT SO CARRYING CATEGORICAL POPS
SOUTH...LIKELY NORTH. PRIMARILY LOOKING AT OVER-RUNNING RAINS AND
ANY LIGHTNING ACTIVITY TO BE BE MINIMAL AT MOST. RAINS AMOUNTS OF
1 TO 2 INCHES EXPECTED ALONG THE INTERSTATE 10 CORRIDOR SOUTH...AND
LESSER AMOUNTS FURTHER NORTH.
RAINS TAPER OFF SATURDAY WITH SYSTEM ADVANCING EAST. REMAINDER OF
WEEKEND LOOKING DRY AND COOL WITH A NORTHERLY FLOW REMAINING IN
PLACE. NEXT POTENTIAL FROPA AND RAIN-MAKER COMING TUESDAY.
&&
.MARINE...LOW PRESSURE DEEPENING AND MOVING ACROSS THE NORTHWEST GULF WILL
BRING STRENGTHENING WINDS AND BUILDING SEAS TONIGHT. WIDESPREAD
RAIN WILL ACCOMPANY THE SYSTEM. WINDS AND RAINS WILL DIMINISH
SATURDAY AS THE SYSTEM EXITS EAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 50 63 46 71 49 / 80 40 10 10 10
KBPT 51 65 46 71 51 / 60 30 10 10 10
KAEX 50 62 43 68 43 / 60 40 10 10 10
KLFT 52 60 47 67 48 / 80 50 10 10 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM CST SATURDAY FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM CAMERON, LA TO HIGH
ISLAND, TX OUT 20 NM...COASTAL WATERS FROM INTRACOASTAL
CITY TO CAMERON, LA OUT 20 NM...COASTAL WATERS FROM LOWER
ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA OUT 20 NM...
WATERS FROM CAMERON, LA TO HIGH ISLAND, TX EXTENDING FROM
20 NM TO 60 NM...WATERS FROM INTRACOASTAL CITY, LA TO
CAMERON, LA EXTENDING FROM 20 NM TO 60 NM...WATERS FROM
LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA EXTENDING
FROM 20 NM TO 60 NM.
GALE WARNING UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING ZONES:
COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL
CITY, LA OUT 20 NM...WATERS FROM LOWER ATCHAFALAYA RIVER TO
INTRACOASTAL CITY, LA EXTENDING FROM 20 NM TO 60 NM.
GALE WARNING UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING ZONES:
COASTAL WATERS FROM CAMERON, LA TO HIGH ISLAND, TX OUT 20
NM...COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON, LA
OUT 20 NM...WATERS FROM CAMERON, LA TO HIGH ISLAND, TX
EXTENDING FROM 20 NM TO 60 NM...WATERS FROM INTRACOASTAL
CITY, LA TO CAMERON, LA EXTENDING FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING
ZONES: CALCASIEU LAKE...SABINE LAKE...VERMILION BAY.
&&
$$
MARCOTTE
000
FXUS64 KLIX 202127
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
327 PM CST FRI NOV 20 2009
.SHORT TERM...
ADVANCING HIGH CLOUD DECK A RESULT OF LARGE CONVECTIVE FLARE-UP IN
THE WEST GULF THIS MORNING THAT HAS SINCE MOVED INTO THE MID-GULF
AND WEAKENED DURING THE PAST FEW HOURS. LARGE UPPER LEVEL
DIVERGENCE STRUCTURE WITH ADVANCING LOW PRESSURE TROUGH SWINGING
ACROSS LOWER TEXAS. PRESSURE FALLS NOTED ALONG THE LOWER TEXAS
COAST VICINITY OF BROWNSVILLE FOR WHAT APPEARS TO BE CYCLOGENESIS.
MEANWHILE...HIGH PRESSURE THAT WAS SETTLED OVER THE SOUTEASTERN
U.S. HAS WEAKENED AND RETREATED NORTHWARD...THEREBY SOFTENING THE
GRADIENT MORE THAN PREVIOUSLY EXPECTED FROM EARLIER MODEL RUNS.
GENERALLY FOLLOWING CONTINUITY OF PAST FORECASTS AND SOMEWHAT IN
LINE WITH GFS. BIGGEST UNCERTAINTIES LIE WITH FUTURE TRACK OF
SURFACE LOW...WHICH MAY BE MUCH FARTHER SOUTH THAN ANY MODELS ARE
INDICATING WITH WAKE DEPRESSION HEIGHT FALLS BEHIND CONVECTIVE
COMPLEX IN GULF CARVING A MORE APT TRAJECTORY THAN MODEL INDICATED.
IF SUCH IS THE CASE...THEN MOST OF THE LAND AREAS WILL BE
SUBJECTED TO ISENTROPIC LIFT STRATIFORM AND ELEVATED CONVECTION
FOR A DURATION OF 12 TO 18 HOURS ONSETTING AROUND MIDNIGHT IN THE
WEST AND EXITING THE EAST AROUND SATURDAY LATE AFTERNOON. THE BULK
OF SURFACE BASED CONVECTION SHOULD REMAIN OVER MARINE AREAS BUT
TRENDS WILL HAVE TO BE MONITORED CLOSELY OVERNIGHT AND
PARTICULARLY SATURDAY MORNING. CURRENT AMBIENT CONDITIONS ARE
RATHER DRY AND CONTINENTALLY INFLUENCED SO THE SATURATION PROCESS
FROM TOP-DOWN WILL BE A RATHER SLOW ONE. AFTER LOW PRESSURE
PASSAGE SATURDAY...HIGH PRESSURE SHOULD BUILD INTO THE REGION AND
MAINTAIN A LONG STRETCH OF SEASONABLY COOL TO MILD TEMPERATURES.
.LONG TERM...
SEASONABLY COOL TO MILD TEMPERATURES AND GENERALLY RAIN FREE DAYS
ARE IN STORE EXCEPT FOR A BRIEF SHOT AT ISOLATED SHOWERS TUESDAY
WITH THE PASSAGE OF RE-ENFORCING COLD FRONT. MOISTURE DOES APPEAR
TO BE LIMITED WITH THIS SYSTEM. THANKSGIVING TRAVEL SHOULD BE
DEVOID OF ANY WEATHER DELAYS ACROSS THE FORECAST AREA.
.AVIATION...
VFR CONDITIONS SHOULD PERSIST AT TERMINALS THRU 00Z. SFC LOW OVER
THE NWRN GULF WILL CONTINUE ON AN ENE TRACK TOWARDS THE AREA. HIGH
LEVEL CLOUDS WILL PROGRESSIVELY INCREASE OVER THE NEXT FEW HOURS.
RAIN SHIELD FROM THIS FEATURE REMAINS SW OF THE AREA BUT WILL
GRADUALLY MOVE IN TONIGHT AN INTO TOMORROW MORNING. CIGS WILL DROP
TO MOSTLY MVFR BY DAYBREAK BUT POSSIBLY LOWER WITH CLUSTERS OF
STRONGER SHOWERS. WINDS WILL SLOWLY TRANSITION FROM ENE TO NNE BY
THE END OF THE PERIOD. MEFFER
&&
.MARINE...
TRENDS WITH SURFACE PRESSURE GRADIENT WILL HAVE TO BE MONITORED
NEXT 12 HOURS BUT DOES APPEAR TO BE HOLD AROUND THE 15-20 KT RANGE
AS LONG AS THE LOW PRESSURE SYSTEM DOES NOT DEEPEN MUCH FURTHER
THAN 1010MB UPON APPROACH. A PERIOD OF HIGHER GUSTS IN THE 25 TO
30 KT RANGE MAY BE POSSIBLE SATURDAY LATE MORNING BUT NOT HIGHLY
CONFIDENT GIVEN THE WEAKEING GRADIENT. WILL POST A`SMALL CRAFT
EXERCISE CAUTION` HEADLINE VALID AFTER 00Z FOR THE COASTAL AREAS
AT THIS TIME WITH THE POSSIBILITY OF SMALL CRAFT ADVISORIES IF
CONDITIONS EXCEED EXPECTATIONS. AFTER LOW PASSES...SOME ENHANCED
WINDS DUE TO SHORT DURATION COLD AIR ADVECTION INTO SUNDAY...THEN
FLATTENING OUT FOR MUCH OF NEXT WEEK. FRONTAL PASSAGE ON TUESDAY
DOES NOT APPEAR TO HAVE MUCH IMPACT ON COASTAL AREAS OTHER THAN TO
RE-ENFORCE HIGH PRESSURE ALREADY IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 48 58 46 64 / 50 80 40 10
BTR 50 59 47 67 / 60 80 20 10
MSY 55 63 52 66 / 70 80 20 10
GPT 53 63 52 64 / 40 80 40 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
24/RR
000
FXUS64 KSHV 202111
AFDSHV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
311 PM CST FRI NOV 20 2009
.DISCUSSION...
KSHV RADAR...NOW BACK UP...SHOWS VERY LIGHT SHOWERS PERSISTING
OVER SE OK...SW AR...AND E TX. WV IMAGERY SHOWS UPPER LOW OVER W
TX MAKING SOME EWD PROGRESS OVER THE LAST FEW HOURS. ISENTROPIC
LIFT ASSOCIATED WITH THE TROF SHOULD ALLOW FOR MORE DEVELOPMENT OF
SHOWERS ACROSS THE SRN ZONES OF DEEP E TX...INTO N LA TONIGHT.
TROF WILL CONTINUE ITS PROGRESSION TONIGHT AND SATURDAY... AND
SHOULD EXIT THE REGION BY LATE SATURDAY EVENING. ALL IN
ALL...RAINFALL TOTALS SHOULD BE MANAGEABLE FOR THE MOST PART...ONLY
AROUND A QUARTER OF AN INCH TO THREE QUARTERS OF AN INCH.
SUNDAY AND MONDAY WILL BRING DRY AND MILD WEATHER...AHEAD OF THE
NEXT SYSTEM. A CLOSED UPPER LOW EJECTS INTO THE PLAINS AND BRINGS
A COLD FRONT THROUGH THE REGION MONDAY NIGHT INTO TUESDAY...
BRINGING SHOWERS AND COOLER TEMPS ALONG WITH IT. ONCE AGAIN...
RAINFALL AMOUNTS SHOULD BE RELATIVELY LIGHT.
THE REMAINDER OF THE EXTENDED APPEARS DRY...WITH A BACK DOOR FRONT
BRINGING A REINFORCING SHOT OF COLD AIR IN ON THANKSGIVING DAY.
THIS MAY VERY WELL BRING OUR FIRST WIDESPREAD FREEZE OF THE
YEAR...MAKING FOR A VERY CHILLY START FOR BLACK FRIDAY SHOPPERS.
&&
.AVIATION...
AN UPPER LEVEL SHORT WAVE OVER SOUTH TEXAS...WILL MOVE SLOWLY EAST
NORTHEAST THROUGH 21/18Z BRINGING A GOOD CHANCE OF SHOWERS TO THE
FOUR STATE AREA TAFS SITES. VFR CIGS MAY LOWER TO MVFR CIGS AT MOST
OF THE TAF SITES TONIGHT...WITH POSSIBLE ISOLATED IFR CIGS AT LFK
THROUGH 21/15Z. AFTER 21/15Z...CIGS WILL GRADUALLY IMPROVE TO VFR BY
21/21Z AS THE SHORT WAVE MOVES TO THE EAST OF THE FOUR STATE AREA.
VSBYS MAY LOWER TO MVFR IN RAIN AT TIMES THROUGH 21/12Z. EAST
SOUTHEAST WINDS MAY SHIFT TO THE NORTHEAST ON SATURDAY AS A SURFACE
LOW PRESSURE SYSTEM MOVES ALONG THE GULF COAST. /03/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 51 60 42 68 45 / 60 60 30 10 0
MLU 47 59 43 66 42 / 40 60 40 10 0
DEQ 49 61 41 65 45 / 40 40 30 10 0
TXK 47 60 44 66 44 / 50 50 30 10 0
ELD 46 60 42 65 43 / 30 50 40 10 0
TYR 50 60 45 69 49 / 60 50 20 10 0
GGG 50 60 43 69 47 / 60 50 20 10 0
LFK 52 61 41 70 48 / 70 60 20 10 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
12/03
000
FXUS64 KLIX 201834
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1234 PM CST FRI NOV 20 2009
.AVIATION...
VFR CONDITIONS SHOULD PERSIST AT TERMINALS THRU 00Z. SFC LOW OVER
THE NWRN GULF WILL CONTINUE ON AN ENE TRACK TOWARDS THE AREA. RAIN
SHIELD FROM THIS FEATURE REMAINS SW OF THE AREA BUT WILL GRADUALLY
MOVE IN TONIGHT AN INTO TOMORROW MORNING. CIGS WILL DROP TO MOSTLY
MVFR BY DAYBREAK BUT POSSIBLY LOWER WITH CLUSTERS OF STRONGER
SHOWERS. WINDS WILL SLOWLY TRANSITION FROM ENE TO NNE BY THE END
OF THE PERIOD.
&&
.PREV DISCUSSION... /ISSUED 721 AM CST FRI NOV 20 2009/
UPDATE...
SOUNDING DISCUSSION...
THE ATMOSPHERE REMAINS DRY AND STABLE WITH A PRECIPITABLE WATER
VALUE OF 0.57 INCHES AND A LIFTED INDEX VALUE OF 7.1. A LARGE
SURFACE INVERSION IS PRESENT ALONG WITH LIGHT AND VARIABLE WINDS FROM
THE SURFACE UP TO 700 MB AND OUT OF THE WEST ALOFT.
PREV DISCUSSION... /ISSUED 358 AM CST FRI NOV 20 2009/
DISCUSSION...
LATEST SURFACE ANALYSIS CONTINUE TO SHOW A 1023MB HIGH OVER
TENNESSEE VALLEY AND AN INVERTED TROUGH FROM SOUTH TEXAS TO
CENTRAL OKLAHOMA. NORTHEAST FLOW WAS NOTED OVER NORTH CENTRAL AND
NORTHEAST GULF. UPPER AIR ANALYSIS SHOWED THE WAVE AXIS FROM THE
TEXAS PANHANDLE TO EL PASO REGION. IR SATELLITE IMAGERY SHOWED
CONVECTION ALONG THE TEXAS COAST AND FROM NORTH CENTRAL TEXAS TO
THE HILLS. INITIAL PLANER FIELDS REVEALED DECREASING THETA-E
VALUES WITH HEIGHT OVER THE WEST GULF AND MUCH OF TEXAS AHEAD OF
THE WAVE. ISOTACH ANALYSIS AT 250 REVEALED THE SOUTHERN STREAM OF
100 TO 110 KNOTS AT THE BASE AND BACK SIDE OF THE WAVE. ALL IN
ALL...AN ACTIVE 100 KNOT JET STREAM ACROSS MEXICO TO THE NORTH
GULF TO NORTH TEXAS. SHORT AND MID RANGE MODELS CONTINUE TO PUSH
THE WAVE EAST THROUGH THE NEXT 36 HOURS BECOMING NEGATIVELY TILTED
FROM ARKLATEX REGION TO THE FORECAST AREA BY SATURDAY AFTERNOON.
SURFACE LOW TRACK CONTINUES ACROSS THE SOUTH HALF OF FORECAST
AREA...GFS IS A LITTLE FASTER AROUND SATURDAY AFTERNOON WHILE
ECMWF TRACKS THE LOW ACROSS SATURDAY NIGHT. 00Z SOUNDING REVEAL A
STRONG INVERSION FROM 900 TO 800MB AND THAT INVERSION STAYS IN
PLACE THROUGH TONIGHT. THETA-E DECREASING WITH HEIGHT WILL EXIST
ABOVE THIS LAYER FOR SATURDAY. IN ADDITION...THE CLOSE PROXIMITY
OF THE UPPER LEVEL WAVE/LOW WITH A 500MB TEMPS -14 TO POSSIBLY
-18C ACROSS THE AREA WILL YIELD A LAPSE RATE SUPPORTING THUNDER.
HOWEVER...WE NEED SURFACE BASE TEMPS IN THE 70S AND THAT AIR MASS
WILL REMAIN SOUTH OF LAND AREAS SATURDAY...A FEW STRONG STORMS
MAY OCCUR ON COASTAL WATERS. WILL CARRY ISOLATED THUNDER SATURDAY
BUT MOST CONVECTION WILL REMAIN NEAR THE COAST SATURDAY. WILL SEE
SOME CLEARING SUNDAY. A SECOND SYSTEM WILL AFFECT THE AREA WITH A
SLIGHT CHANCE OF RAIN TUESDAY AND ANOTHER DRY SYSTEM FOR
THURSDAY...BOTH WILL KEEP TEMPS AT OR BELOW NORMS FOR NEXT WEEK.
AVIATION...
VFR CONDITIONS WILL BE THE RULE THROUGH 06Z SATURDAY...OTHER THAN
POSSIBLY A FEW HOURS OF MVFR VSBYS DUE TO HAZE OR LIGHT FOG AROUND
SUNRISE...ESPECIALLY AT KBTR. AS LOW MOVES FROM WESTERN GULF...WE
SHOULD GRADUALLY SEE THE COLUMN MOISTEN FROM THE TOP DOWN TONIGHT
WITH CEILINGS IN THE MVFR RANGE BY THE END OF THE PERIOD FOR THE
NEXT FORECAST PACKAGE...09Z-12Z SATURDAY AT KBTR...AND BEYOND THAT
FOR ALL OTHER TERMINALS. 35
MARINE...
MAIN CONCERN WILL BE WINDS SATURDAY. MODEL SOLUTIONS STILL RATHER
JUMPY AS FAR AS CONTINUITY GOES. WIND GRIDS WERE AGAIN BASED ON 00Z
ECMWF/NAM SOLUTIONS. 00Z GFS WAS AN OUTLIER DUE TO SPEED OF SYSTEM
MOVEMENT BEING MUCH QUICKER THAN OTHER MODELS. WIND SPEEDS ON GFS
ALSO APPEAR A LITTLE HIGHER THAN REALITY AT THIS POINT.
WE WILL NOT GET INTO EXERCISE CAUTION WIND SPEEDS UNTIL AFTER 06Z
SATURDAY...AND PROBABLY NOT INTO THE ADVISORY RANGE...MAINLY OVER
WESTERN WATERS...UNTIL MIDDAY ON SATURDAY. WILL HOLD OFF ON ANY
HEADLINES NOW...BUT EXPECT BY THE 21Z PACKAGE TODAY...ADVISORIES
WILL PROBABLY NEED RAISED. CONDITIONS SHOULD SETTLE DOWN PRETTY
QUICKLY SUNDAY. WINDS PROBABLY WILL REMAIN BELOW HEADLINE LEVELS FOR
SEVERAL DAYS AFTER THAT. 35
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 49 58 47 64 / 50 80 30 10
BTR 50 61 49 67 / 60 80 20 10
MSY 56 64 52 68 / 60 80 20 10
GPT 53 63 52 64 / 40 80 30 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
000
FXUS64 KLCH 201729
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
1129 AM CST FRI NOV 20 2009
.AVIATION...
FOR THE 20/18Z TAF ISSUANCE...
A LARGE AREA OF RAIN EXTENDING FROM THE NORTHWEST GULF INTO
SOUTHEAST TEXAS MOVING VERY SLOWLY TO THE EAST-NORTHEAST. UPPER
LEVEL TROUGH OVER CENTRAL TEXAS WILL CONTINUE TO SLOWLY MOVE TO
THE EAST AND ACROSS THE REGION TONIGHT AND EARLY SATURDAY.
AS THIS SYSTEM MOVES CLOSER...ISENTROPIC LIFT WILL INCREASE AND
AREA OF RAIN WILL EXPAND TO THE EAST REACHING MOST TAF SITES BY
LATE THIS AFTERNOON. EXPECT THE POTENTIAL FOR THE HEAVIEST AND
STEADIEST RAINFALL TO OCCUR LATE THIS EVENING AND OVERNIGHT. WITH
THIS...CEILINGS AND VISIBILITIES WILL LOWER TO MVFR LEVELS.
ALSO...GRADIENT WILL TIGHTEN...ESPECIALLY OVER SOUTHERN TAF
SITES THIS EVENING...AS SURFACE WAVE MOVES JUST OFF THE COAST.
BREEZY EASTERLY WINDS WITH GUSTS TO AROUND 20 KNOTS POSSIBLE
THROUGH THE NIGHT.
RUA
&&
.PREV DISCUSSION... /ISSUED 1041 AM CST FRI NOV 20 2009/
UPDATE...NEW DISCUSSION AVAILABLE.
DISCUSSION...MINOR TWEAKS TO ZONES AT THIS TIME INCLUDING BUMPING
UP POPS SLIGHTLY OVER THE EASTERN HALF OF THE AREA. CURRENT COASTAL
WATERS PRECIP PICKED UP BEST BY GFS WITH ASSOCIATED MOS SHOWING
HIGHER POPS EAST. HARD TO MAKE ANY SIGNIFICANT CHANGES AT THIS
TIME WITH MODELS HAVING A DIFFICULT TIME COMING TOGETHER ON
SOLUTIONS.
MARCOTTE
PREV DISCUSSION... /ISSUED 610 AM CST FRI NOV 20 2009/
DISCUSSION...
12Z TAF PACKAGE.
AVIATION...
CHALLENGING AVIATION FORECAST ON TAP FOR THE NEXT 24 TO 48 HOURS.
VIGOROUS UPPER LEVEL STORM SYSTEM SPINNING THROUGH NORTHERN MEXICO
IS SPURRING SFC CYCLOGENESIS OVER SOUTHERN TX THIS MORNING. THIS
SFC LOW IS FORECAST TO TRACK GENERALLY EASTWARD OVER THE GULF
WATERS TODAY AND TONIGHT. THE SPEED AND EXACT PATH OF THE LOW IS A
MATTER OF DEBATE...WITH MODEL FORECASTS DIFFERING UP TO 12 HOURS
AND 200 MILES. GENERAL IDEA IS FOR A MAINLY LIGHT TO MODERATE RAIN
SHIELD...WITH EMBEDDED HEAVIER SHOWERS AND ISOLATED THUNDER...TO
SPREAD INTO THE AREA FROM WEST TO EAST IN CONJUNCTION WITH THE
MOVEMENT OF THE LOW. MADE AN EFFORT TO TIME THE INCOMING RAIN
BASED ON A COMBINATION OF LATEST RADAR/SATELLITE/SURFACE DATA AND
LATEST MODEL GUIDANCE. IN ANY EVENT...FLIGHT CONDITIONS SHOULD
GENERALLY REMAIN VFR TO MVFR IN THE LIGHT TO MODERATE
RAIN...THOUGH BRIEF PERIODS OF LOWER CATEGORIES ARE POSSIBLE
SHOULD ANY HEAVIER SHOWERS OR THUNDER MOVE OVER A TERMINAL. THIS
WOULD BE MOST LIKELY TO OCCUR AT THE COASTAL SITES.
EAST WINDS WILL ALSO BE ON THE INCREASE AT THE COASTAL
SITES...THOUGH EXACTLY HOW HIGH THEY GET DEPENDS ON THE
TRACK/STRENGTH OF THE LOW.
PREV DISCUSSION... /ISSUED 447 AM CST FRI NOV 20 2009/
DISCUSSION...
RAPID WEATHER CHANGES IN PROGRESS AS GULF LOW TAKING SHAPE OFF
THE LOWER TEXAS COAST. ALTHOUGH MODELS REMAIN IN GENERAL AGREEMENT
ON EVOLUTION OF THIS WEATHER EVENT...TRACK OF SURFACE LOW REMAINS
SOMEWHAT UNCERTAIN WITH ECMWF FURTHEST NORTH AND NAM FURTHEST
SOUTH. WITH SURFACE LOW SETTING UP EAST OF CRP...A MIDDLE OF THE
ROAD SOLUTION TAKING THE LOW TOWARDS TERREBONE PARISH AND KEEPING
THE WARM SECTOR SOUTH OF OUR INLAND AREAS SEEMS MOST REASONABLE AT
THIS TIME. LATEST RADAR IMAGERY SHOWS A LARGE AREA OF SHOWERS AND
THUNDERSTORMS HAS DEVELOPED ACROSS MUCH OF COASTAL TEXAS...WITH
RAIN SHIELD NOW SPREADING INTO OUR SOUTHEAST TEXAS COUNTIES AND
COASTAL WATERS. HOWEVER...RAIN HAS RUN INTO AN ATMOSPHERIC BRICK
WALL AS CONSIDERABLE DRY AIR IN PLACE OVER OUR FORECAST AREA
EVAPORATES THE PRECIPITATION. HOWEVER...MODELS CONTINUE TO
INDICATE EVENTUAL MOISTENING OF THE AIRMASS WILL RESULT IN SHOWERS
AND THUNDERSTORMS SPREADING OVER THE FORECAST AREA FROM WEST TO
EAST DURING THE DAY INTO TONIGHT. HAVE ADJUSTED POPS BUT STILL
CALLING FOR HIGH PRECIP CHANCES ALONG AND SOUTH OF THE I-10
CORRIDOR...WITH BEST CHANCES IN THE COASTAL WATERS. LATEST HPC
GUIDANCE INDICATES RAINFALL TOTALS OF 1 TO 3 INCHES WILL BE
POSSIBLE IN SOUTHERN ZONES...MAINLY NEAR THE COAST...WITH LESS
THAN AN INCH EXPECTED IN NORTHERN ZONES.
WITH PRESSURE GRADIENT TIGHTENING BETWEEN THE GULF LOW AND HIGH
PRESSURE TO THE NORTHEAST...NUMEROUS WEATHER STATIONS ALONG THE
TEXAS COAST HAVE SEEN WIND GUSTS OF 25 TO 35 KNOTS ALREADY THIS
MORNING. AS THE GULF LOW APPROACHES OUR AREA THIS AFTERNOON AND
MOVES SOUTH OF OUR COASTLINE THIS EVENING...THE TIGHT PRESSURE
GRADIENT ON THE NORTH SIDE OF THE LOW MAY RESULT IN WINDS NEAR
LAKE WIND ADVISORY CRITERIA AS SHOWN BY THE GFS AND
ECMWF...ESPECIALLY NEAR THE COAST. THUS HAVE ISSUED A LAKE WIND
ADVISORY FOR COASTAL SOUTHEAST TEXAS AND PORTIONS OF SOUTHWEST
LOUISIANA...WITH STRONGEST WINDS MAINLY SOUTH OF THE HIGHWAY 73
AND HIGHWAY 14 CORRIDORS.
RAINFALL WILL COME TO AN END FROM WEST TO EAST ON SATURDAY AS GULF
LOW MOVES EAST OF THE REGION...WITH DRY WEATHER EXPECTED ON SUNDAY
AND MONDAY. GLOBAL MODELS CONTINUE TO INDICATE A COLD FRONT WILL
PUSH SOUTHWARD MONDAY NIGHT AND TUESDAY...BUT LIMITED MOISTURE
RETURN AHEAD OF THE BOUNDARY INDICATES ONLY SLIGHT CHANCE POPS
ARE WARRANTED AT THIS TIME.
MARINE...
SIGNIFICANT WEATHER IMPACTS EXPECTED ACROSS OUR COASTAL WATERS
TODAY AND TONIGHT AS GULF LOW STRENGTHENS AND MOVES NORTHEASTWARD
TOWARDS SOUTHEASTERN LOUISIANA. EASTERLY WINDS WILL RAPIDLY
STRENGTHEN TODAY AS A TIGHT PRESSURE GRADIENT DEVELOPS ON THE
NORTH SIDE OF THE LOW CENTER...WITH SUSTAINED WINDS AND GUSTS
NEAR GALE FORCE AT TIMES FROM THIS AFTERNOON THROUGH TONIGHT. IN
FACT...BUOY OBS AND EVEN INLAND STATIONS ALONG THE TEXAS COAST
HAVE ALREADY SEEN WINDS GUSTS AROUND 35 KNOTS THIS MORNING. WAVE
HEIGHTS CURRENTLY RUNNING AROUND 5 FEET AT BUOY 42035...AND ARE
EXPECTED TO CONTINUE TO INCREASE THROUGH THE DAY WITH WAVES UP TO
10 FEET TONIGHT IN THE OUTER WATERS. IN ADDITION...NUMEROUS
SHOWERS AND THUNDERSTORMS ARE ALREADY SPREADING ACROSS THE COASTAL
WATERS...AND SOME OF THESE COULD REACH STRONG TO SEVERE LEVELS.
TIDES ARE CURRENTLY RUNNING UP TO ONE FOOT ABOVE NORMAL. AS THE
EASTERLY WINDS INCREASE DURING THE DAY...TIDES BETWEEN ONE AND TWO
FEET ABOVE NORMAL WILL BE POSSIBLE ALONG OUR COASTLINE WHICH MAY
CAUSE SOME MINOR COASTAL FLOODING ISSUES THIS EVENING AT TIME OF
HIGH TIDE. UNCERTAINTY EXISTS ON HOW HIGH TIDES WILL GET AS WINDS
ARE EXPECTED TO BACK TO A MORE NORTHEASTERLY DIRECTION TONIGHT AS
THE LOW CENTER PASSES NEAR OR SOUTH OF THE COASTAL WATERS. THUS
AREAS AROUND VERMILION BAY MAY SEE MOST IMPACTS FROM ANY COASTAL
FLOODING THIS EVENING AS WINDS WILL REMAIN EASTERLY FOR A LONGER
PERIOD OF TIME VERSUS AREAS FURTHER WEST.
WINDS AND SEAS WILL SUBSIDE ON SATURDAY AS SYSTEM PUSHES EAST OF
OUR REGION...WITH OFFSHORE FLOW EXPECTED INTO SATURDAY NIGHT. ONSHORE
FLOW RETURNS ON SUNDAY AND MONDAY...WITH A COLD FRONT EXPECTED TO
PUSH SOUTHWARD THROUGH THE AREA ON TUESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 64 51 61 45 69 / 60 80 60 10 0
KBPT 64 51 61 46 68 / 90 80 50 10 0
KAEX 62 47 56 43 66 / 30 60 60 10 0
KLFT 65 51 61 45 66 / 30 80 80 10 0
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...LAKE WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE FOLLOWING
ZONES: CALCASIEU...CAMERON...VERMILION.
COASTAL FLOOD ADVISORY UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING
ZONES: CALCASIEU...CAMERON...IBERIA...LOWER ST. MARTIN...
ST. MARY...VERMILION.
TX...LAKE WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE FOLLOWING
ZONES: JEFFERSON...ORANGE.
COASTAL FLOOD ADVISORY UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING
ZONES: JEFFERSON...ORANGE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM LOWER ATCHAFALAYA
RIVER TO INTRACOASTAL CITY, LA OUT 20 NM...WATERS FROM
LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA EXTENDING
FROM 20 NM TO 60 NM.
GALE WARNING FROM 6 PM THIS EVENING TO 6 AM CST SATURDAY FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM LOWER ATCHAFALAYA
RIVER TO INTRACOASTAL CITY, LA OUT 20 NM...WATERS FROM
LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA EXTENDING
FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM CAMERON, LA TO HIGH ISLAND, TX
OUT 20 NM...COASTAL WATERS FROM INTRACOASTAL CITY TO
CAMERON, LA OUT 20 NM...WATERS FROM CAMERON, LA TO HIGH
ISLAND, TX EXTENDING FROM 20 NM TO 60 NM...WATERS FROM
INTRACOASTAL CITY, LA TO CAMERON, LA EXTENDING FROM 20 NM
TO 60 NM.
GALE WARNING UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING ZONES:
COASTAL WATERS FROM CAMERON, LA TO HIGH ISLAND, TX OUT 20
NM...COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON, LA
OUT 20 NM...WATERS FROM CAMERON, LA TO HIGH ISLAND, TX
EXTENDING FROM 20 NM TO 60 NM...WATERS FROM INTRACOASTAL
CITY, LA TO CAMERON, LA EXTENDING FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING
ZONES: CALCASIEU LAKE...SABINE LAKE...VERMILION BAY.
&&
$$
000
FXUS64 KLCH 201641
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
1041 AM CST FRI NOV 20 2009
.UPDATE...NEW DISCUSSION AVAILABLE.
&&
.DISCUSSION...MINOR TWEAKS TO ZONES AT THIS TIME INCLUDING BUMPING
UP POPS SLIGHTLY OVER THE EASTERN HALF OF THE AREA. CURRENT COASTAL
WATERS PRECIP PICKED UP BEST BY GFS WITH ASSOCIATED MOS SHOWING
HIGHER POPS EAST. HARD TO MAKE ANY SIGNIFICANT CHANGES AT THIS
TIME WITH MODELS HAVING A DIFFICULT TIME COMING TOGETHER ON
SOLUTIONS.
MARCOTTE
&&
.PREV DISCUSSION... /ISSUED 610 AM CST FRI NOV 20 2009/
DISCUSSION...
12Z TAF PACKAGE.
AVIATION...
CHALLENGING AVIATION FORECAST ON TAP FOR THE NEXT 24 TO 48 HOURS.
VIGOROUS UPPER LEVEL STORM SYSTEM SPINNING THROUGH NORTHERN MEXICO
IS SPURRING SFC CYCLOGENESIS OVER SOUTHERN TX THIS MORNING. THIS
SFC LOW IS FORECAST TO TRACK GENERALLY EASTWARD OVER THE GULF
WATERS TODAY AND TONIGHT. THE SPEED AND EXACT PATH OF THE LOW IS A
MATTER OF DEBATE...WITH MODEL FORECASTS DIFFERING UP TO 12 HOURS
AND 200 MILES. GENERAL IDEA IS FOR A MAINLY LIGHT TO MODERATE RAIN
SHIELD...WITH EMBEDDED HEAVIER SHOWERS AND ISOLATED THUNDER...TO
SPREAD INTO THE AREA FROM WEST TO EAST IN CONJUNCTION WITH THE
MOVEMENT OF THE LOW. MADE AN EFFORT TO TIME THE INCOMING RAIN
BASED ON A COMBINATION OF LATEST RADAR/SATELLITE/SURFACE DATA AND
LATEST MODEL GUIDANCE. IN ANY EVENT...FLIGHT CONDITIONS SHOULD
GENERALLY REMAIN VFR TO MVFR IN THE LIGHT TO MODERATE
RAIN...THOUGH BRIEF PERIODS OF LOWER CATEGORIES ARE POSSIBLE
SHOULD ANY HEAVIER SHOWERS OR THUNDER MOVE OVER A TERMINAL. THIS
WOULD BE MOST LIKELY TO OCCUR AT THE COASTAL SITES.
EAST WINDS WILL ALSO BE ON THE INCREASE AT THE COASTAL
SITES...THOUGH EXACTLY HOW HIGH THEY GET DEPENDS ON THE
TRACK/STRENGTH OF THE LOW.
PREV DISCUSSION... /ISSUED 447 AM CST FRI NOV 20 2009/
DISCUSSION...
RAPID WEATHER CHANGES IN PROGRESS AS GULF LOW TAKING SHAPE OFF
THE LOWER TEXAS COAST. ALTHOUGH MODELS REMAIN IN GENERAL AGREEMENT
ON EVOLUTION OF THIS WEATHER EVENT...TRACK OF SURFACE LOW REMAINS
SOMEWHAT UNCERTAIN WITH ECMWF FURTHEST NORTH AND NAM FURTHEST
SOUTH. WITH SURFACE LOW SETTING UP EAST OF CRP...A MIDDLE OF THE
ROAD SOLUTION TAKING THE LOW TOWARDS TERREBONE PARISH AND KEEPING
THE WARM SECTOR SOUTH OF OUR INLAND AREAS SEEMS MOST REASONABLE AT
THIS TIME. LATEST RADAR IMAGERY SHOWS A LARGE AREA OF SHOWERS AND
THUNDERSTORMS HAS DEVELOPED ACROSS MUCH OF COASTAL TEXAS...WITH
RAIN SHIELD NOW SPREADING INTO OUR SOUTHEAST TEXAS COUNTIES AND
COASTAL WATERS. HOWEVER...RAIN HAS RUN INTO AN ATMOSPHERIC BRICK
WALL AS CONSIDERABLE DRY AIR IN PLACE OVER OUR FORECAST AREA
EVAPORATES THE PRECIPITATION. HOWEVER...MODELS CONTINUE TO
INDICATE EVENTUAL MOISTENING OF THE AIRMASS WILL RESULT IN SHOWERS
AND THUNDERSTORMS SPREADING OVER THE FORECAST AREA FROM WEST TO
EAST DURING THE DAY INTO TONIGHT. HAVE ADJUSTED POPS BUT STILL
CALLING FOR HIGH PRECIP CHANCES ALONG AND SOUTH OF THE I-10
CORRIDOR...WITH BEST CHANCES IN THE COASTAL WATERS. LATEST HPC
GUIDANCE INDICATES RAINFALL TOTALS OF 1 TO 3 INCHES WILL BE
POSSIBLE IN SOUTHERN ZONES...MAINLY NEAR THE COAST...WITH LESS
THAN AN INCH EXPECTED IN NORTHERN ZONES.
WITH PRESSURE GRADIENT TIGHTENING BETWEEN THE GULF LOW AND HIGH
PRESSURE TO THE NORTHEAST...NUMEROUS WEATHER STATIONS ALONG THE
TEXAS COAST HAVE SEEN WIND GUSTS OF 25 TO 35 KNOTS ALREADY THIS
MORNING. AS THE GULF LOW APPROACHES OUR AREA THIS AFTERNOON AND
MOVES SOUTH OF OUR COASTLINE THIS EVENING...THE TIGHT PRESSURE
GRADIENT ON THE NORTH SIDE OF THE LOW MAY RESULT IN WINDS NEAR
LAKE WIND ADVISORY CRITERIA AS SHOWN BY THE GFS AND
ECMWF...ESPECIALLY NEAR THE COAST. THUS HAVE ISSUED A LAKE WIND
ADVISORY FOR COASTAL SOUTHEAST TEXAS AND PORTIONS OF SOUTHWEST
LOUISIANA...WITH STRONGEST WINDS MAINLY SOUTH OF THE HIGHWAY 73
AND HIGHWAY 14 CORRIDORS.
RAINFALL WILL COME TO AN END FROM WEST TO EAST ON SATURDAY AS GULF
LOW MOVES EAST OF THE REGION...WITH DRY WEATHER EXPECTED ON SUNDAY
AND MONDAY. GLOBAL MODELS CONTINUE TO INDICATE A COLD FRONT WILL
PUSH SOUTHWARD MONDAY NIGHT AND TUESDAY...BUT LIMITED MOISTURE
RETURN AHEAD OF THE BOUNDARY INDICATES ONLY SLIGHT CHANCE POPS
ARE WARRANTED AT THIS TIME.
MARINE...
SIGNIFICANT WEATHER IMPACTS EXPECTED ACROSS OUR COASTAL WATERS
TODAY AND TONIGHT AS GULF LOW STRENGTHENS AND MOVES NORTHEASTWARD
TOWARDS SOUTHEASTERN LOUISIANA. EASTERLY WINDS WILL RAPIDLY
STRENGTHEN TODAY AS A TIGHT PRESSURE GRADIENT DEVELOPS ON THE
NORTH SIDE OF THE LOW CENTER...WITH SUSTAINED WINDS AND GUSTS
NEAR GALE FORCE AT TIMES FROM THIS AFTERNOON THROUGH TONIGHT. IN
FACT...BUOY OBS AND EVEN INLAND STATIONS ALONG THE TEXAS COAST
HAVE ALREADY SEEN WINDS GUSTS AROUND 35 KNOTS THIS MORNING. WAVE
HEIGHTS CURRENTLY RUNNING AROUND 5 FEET AT BUOY 42035...AND ARE
EXPECTED TO CONTINUE TO INCREASE THROUGH THE DAY WITH WAVES UP TO
10 FEET TONIGHT IN THE OUTER WATERS. IN ADDITION...NUMEROUS
SHOWERS AND THUNDERSTORMS ARE ALREADY SPREADING ACROSS THE COASTAL
WATERS...AND SOME OF THESE COULD REACH STRONG TO SEVERE LEVELS.
TIDES ARE CURRENTLY RUNNING UP TO ONE FOOT ABOVE NORMAL. AS THE
EASTERLY WINDS INCREASE DURING THE DAY...TIDES BETWEEN ONE AND TWO
FEET ABOVE NORMAL WILL BE POSSIBLE ALONG OUR COASTLINE WHICH MAY
CAUSE SOME MINOR COASTAL FLOODING ISSUES THIS EVENING AT TIME OF
HIGH TIDE. UNCERTAINTY EXISTS ON HOW HIGH TIDES WILL GET AS WINDS
ARE EXPECTED TO BACK TO A MORE NORTHEASTERLY DIRECTION TONIGHT AS
THE LOW CENTER PASSES NEAR OR SOUTH OF THE COASTAL WATERS. THUS
AREAS AROUND VERMILION BAY MAY SEE MOST IMPACTS FROM ANY COASTAL
FLOODING THIS EVENING AS WINDS WILL REMAIN EASTERLY FOR A LONGER
PERIOD OF TIME VERSUS AREAS FURTHER WEST.
WINDS AND SEAS WILL SUBSIDE ON SATURDAY AS SYSTEM PUSHES EAST OF
OUR REGION...WITH OFFSHORE FLOW EXPECTED INTO SATURDAY NIGHT. ONSHORE
FLOW RETURNS ON SUNDAY AND MONDAY...WITH A COLD FRONT EXPECTED TO
PUSH SOUTHWARD THROUGH THE AREA ON TUESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 64 51 61 45 69 / 60 80 60 10 0
KBPT 64 51 61 46 68 / 90 80 50 10 0
KAEX 62 47 56 43 66 / 30 60 60 10 0
KLFT 65 51 61 45 66 / 30 80 80 10 0
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...LAKE WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE FOLLOWING
ZONES: CALCASIEU...CAMERON...VERMILION.
COASTAL FLOOD ADVISORY UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING
ZONES: CALCASIEU...CAMERON...IBERIA...LOWER ST. MARTIN...
ST. MARY...VERMILION.
TX...LAKE WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE FOLLOWING
ZONES: JEFFERSON...ORANGE.
COASTAL FLOOD ADVISORY UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING
ZONES: JEFFERSON...ORANGE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM LOWER ATCHAFALAYA
RIVER TO INTRACOASTAL CITY, LA OUT 20 NM...WATERS FROM
LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA EXTENDING
FROM 20 NM TO 60 NM.
GALE WARNING FROM 6 PM THIS EVENING TO 6 AM CST SATURDAY FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM LOWER ATCHAFALAYA
RIVER TO INTRACOASTAL CITY, LA OUT 20 NM...WATERS FROM
LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA EXTENDING
FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM CAMERON, LA TO HIGH ISLAND, TX
OUT 20 NM...COASTAL WATERS FROM INTRACOASTAL CITY TO
CAMERON, LA OUT 20 NM...WATERS FROM CAMERON, LA TO HIGH
ISLAND, TX EXTENDING FROM 20 NM TO 60 NM...WATERS FROM
INTRACOASTAL CITY, LA TO CAMERON, LA EXTENDING FROM 20 NM
TO 60 NM.
GALE WARNING UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING ZONES:
COASTAL WATERS FROM CAMERON, LA TO HIGH ISLAND, TX OUT 20
NM...COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON, LA
OUT 20 NM...WATERS FROM CAMERON, LA TO HIGH ISLAND, TX
EXTENDING FROM 20 NM TO 60 NM...WATERS FROM INTRACOASTAL
CITY, LA TO CAMERON, LA EXTENDING FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING
ZONES: CALCASIEU LAKE...SABINE LAKE...VERMILION BAY.
&&
$$
000
FXUS64 KSHV 201627
AFDSHV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
1027 AM CST FRI NOV 20 2009
.DISCUSSION...
KSHV RADAR SHOWS ONGOING PRECIP OVER NE TX/SW AR REMAINING NEARLY
STATIONARY. WV IMAGERY SHOWS UPPER TROF OVER W TX MAKING VERY SLOW
PROGRESS EWD. EXPECTING THIS TROF TO CONTINUE TO PUSH EWD
TODAY...FORCING SHOWERS AND ISOLATED THUNDERSTORMS TO BECOME MORE
WIDESPREAD ACROSS DEEP E TX AND N LA. THAT SAID...MADE ONLY MINOR
ADJUSTMENTS TO POPS FOR THIS AFTERNOON. ALSO MADE SOME TWEAKS TO
TEMPS TO LOWER WHERE RAIN IS OCCURRING. OTHERWISE...NO OTHER
CHANGES APPEAR NECESSARY. UPDATED ZONES WILL BE OUT SHORTLY. /12/
&&
.AVIATION...
AN UPPER LEVEL SHORT WAVE OVER SOUTH TEXAS...WILL MOVE SLOWLY EAST
NORTHEAST THROUGH 21/18Z BRINGING A GOOD CHANCE OF SHOWERS TO THE
FOUR STATE AREA TAFS SITES. VFR CIGS MAY LOWER TO MVFR CIGS AT MOST
OF THE TAF SITES...WITH POSSIBLE ISOLATED IFR CIGS AT LFK THROUGH
21/15Z. AFTER 21/15Z...CIGS WILL GRADUALLY IMPROVE TO VFR BY 21/21Z
AS THE SHORT WAVE MOVES TO THE EAST OF THE FOUR STATE AREA. VSBYS
MAY LOWER TO MVFR IN RAIN AT TIMES THROUGH 21/12Z. EAST SOUTHEAST
WINDS MAY SHIFT TO THE NORTHEAST ON SATURDAY AS A SURFACE LOW
PRESSURE SYSTEM MOVES ALONG THE GULF COAST. /03/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 61 47 60 43 68 / 50 60 60 30 0
MLU 63 47 58 46 65 / 30 70 70 40 0
DEQ 58 46 61 41 67 / 60 30 40 30 0
TXK 58 47 61 42 67 / 60 50 50 30 0
ELD 62 46 60 45 67 / 30 50 50 40 0
TYR 60 47 61 42 69 / 70 60 50 20 0
GGG 61 47 61 42 69 / 70 60 50 20 0
LFK 62 49 61 41 70 / 70 80 60 20 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
12/03
000
FXUS64 KLIX 201321
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
721 AM CST FRI NOV 20 2009
.UPDATE...
.SOUNDING DISCUSSION...
THE ATMOSPHERE REMAINS DRY AND STABLE WITH A PRECIPITABLE WATER
VALUE OF 0.57 INCHES AND A LIFTED INDEX VALUE OF 7.1. A LARGE
SURFACE INVERSION IS PRESENT ALONG WITH LIGHT AND VARIABLE WINDS FROM
THE SURFACE UP TO 700 MB AND OUT OF THE WEST ALOFT.
&&
.PREV DISCUSSION... /ISSUED 358 AM CST FRI NOV 20 2009/
DISCUSSION...
LATEST SURFACE ANALYSIS CONTINUE TO SHOW A 1023MB HIGH OVER
TENNESSEE VALLEY AND AN INVERTED TROUGH FROM SOUTH TEXAS TO
CENTRAL OKLAHOMA. NORTHEAST FLOW WAS NOTED OVER NORTH CENTRAL AND
NORTHEAST GULF. UPPER AIR ANALYSIS SHOWED THE WAVE AXIS FROM THE
TEXAS PANHANDLE TO EL PASO REGION. IR SATELLITE IMAGERY SHOWED
CONVECTION ALONG THE TEXAS COAST AND FROM NORTH CENTRAL TEXAS TO
THE HILLS. INITIAL PLANER FIELDS REVEALED DECREASING THETA-E
VALUES WITH HEIGHT OVER THE WEST GULF AND MUCH OF TEXAS AHEAD OF
THE WAVE. ISOTACH ANALYSIS AT 250 REVEALED THE SOUTHERN STREAM OF
100 TO 110 KNOTS AT THE BASE AND BACK SIDE OF THE WAVE. ALL IN
ALL...AN ACTIVE 100 KNOT JET STREAM ACROSS MEXICO TO THE NORTH
GULF TO NORTH TEXAS. SHORT AND MID RANGE MODELS CONTINUE TO PUSH
THE WAVE EAST THROUGH THE NEXT 36 HOURS BECOMING NEGATIVELY TILTED
FROM ARKLATEX REGION TO THE FORECAST AREA BY SATURDAY AFTERNOON.
SURFACE LOW TRACK CONTINUES ACROSS THE SOUTH HALF OF FORECAST
AREA...GFS IS A LITTLE FASTER AROUND SATURDAY AFTERNOON WHILE
ECMWF TRACKS THE LOW ACROSS SATURDAY NIGHT. 00Z SOUNDING REVEAL A
STRONG INVERSION FROM 900 TO 800MB AND THAT INVERSION STAYS IN
PLACE THROUGH TONIGHT. THETA-E DECREASING WITH HEIGHT WILL EXIST
ABOVE THIS LAYER FOR SATURDAY. IN ADDITION...THE CLOSE PROXIMITY
OF THE UPPER LEVEL WAVE/LOW WITH A 500MB TEMPS -14 TO POSSIBLY
-18C ACROSS THE AREA WILL YIELD A LAPSE RATE SUPPORTING THUNDER.
HOWEVER...WE NEED SURFACE BASE TEMPS IN THE 70S AND THAT AIR MASS
WILL REMAIN SOUTH OF LAND AREAS SATURDAY...A FEW STRONG STORMS
MAY OCCUR ON COASTAL WATERS. WILL CARRY ISOLATED THUNDER SATURDAY
BUT MOST CONVECTION WILL REMAIN NEAR THE COAST SATURDAY. WILL SEE
SOME CLEARING SUNDAY. A SECOND SYSTEM WILL AFFECT THE AREA WITH A
SLIGHT CHANCE OF RAIN TUESDAY AND ANOTHER DRY SYSTEM FOR
THURSDAY...BOTH WILL KEEP TEMPS AT OR BELOW NORMS FOR NEXT WEEK.
AVIATION...
VFR CONDITIONS WILL BE THE RULE THROUGH 06Z SATURDAY...OTHER THAN
POSSIBLY A FEW HOURS OF MVFR VSBYS DUE TO HAZE OR LIGHT FOG AROUND
SUNRISE...ESPECIALLY AT KBTR. AS LOW MOVES FROM WESTERN GULF...WE
SHOULD GRADUALLY SEE THE COLUMN MOISTEN FROM THE TOP DOWN TONIGHT
WITH CEILINGS IN THE MVFR RANGE BY THE END OF THE PERIOD FOR THE
NEXT FORECAST PACKAGE...09Z-12Z SATURDAY AT KBTR...AND BEYOND THAT
FOR ALL OTHER TERMINALS. 35
MARINE...
MAIN CONCERN WILL BE WINDS SATURDAY. MODEL SOLUTIONS STILL RATHER
JUMPY AS FAR AS CONTINUITY GOES. WIND GRIDS WERE AGAIN BASED ON 00Z
ECMWF/NAM SOLUTIONS. 00Z GFS WAS AN OUTLIER DUE TO SPEED OF SYSTEM
MOVEMENT BEING MUCH QUICKER THAN OTHER MODELS. WIND SPEEDS ON GFS
ALSO APPEAR A LITTLE HIGHER THAN REALITY AT THIS POINT.
WE WILL NOT GET INTO EXERCISE CAUTION WIND SPEEDS UNTIL AFTER 06Z
SATURDAY...AND PROBABLY NOT INTO THE ADVISORY RANGE...MAINLY OVER
WESTERN WATERS...UNTIL MIDDAY ON SATURDAY. WILL HOLD OFF ON ANY
HEADLINES NOW...BUT EXPECT BY THE 21Z PACKAGE TODAY...ADVISORIES
WILL PROBABLY NEED RAISED. CONDITIONS SHOULD SETTLE DOWN PRETTY
QUICKLY SUNDAY. WINDS PROBABLY WILL REMAIN BELOW HEADLINE LEVELS FOR
SEVERAL DAYS AFTER THAT. 35
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 65 49 58 48 / 10 50 80 30
BTR 65 50 62 49 / 20 60 80 20
MSY 67 56 64 52 / 10 60 80 20
GPT 67 53 63 52 / 10 40 80 30
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
000
FXUS64 KLCH 201210
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
610 AM CST FRI NOV 20 2009
.DISCUSSION...
12Z TAF PACKAGE.
&&
.AVIATION...
CHALLENGING AVIATION FORECAST ON TAP FOR THE NEXT 24 TO 48 HOURS.
VIGOROUS UPPER LEVEL STORM SYSTEM SPINNING THROUGH NORTHERN MEXICO
IS SPURRING SFC CYCLOGENESIS OVER SOUTHERN TX THIS MORNING. THIS
SFC LOW IS FORECAST TO TRACK GENERALLY EASTWARD OVER THE GULF
WATERS TODAY AND TONIGHT. THE SPEED AND EXACT PATH OF THE LOW IS A
MATTER OF DEBATE...WITH MODEL FORECASTS DIFFERING UP TO 12 HOURS
AND 200 MILES. GENERAL IDEA IS FOR A MAINLY LIGHT TO MODERATE RAIN
SHIELD...WITH EMBEDDED HEAVIER SHOWERS AND ISOLATED THUNDER...TO
SPREAD INTO THE AREA FROM WEST TO EAST IN CONJUNCTION WITH THE
MOVEMENT OF THE LOW. MADE AN EFFORT TO TIME THE INCOMING RAIN
BASED ON A COMBINATION OF LATEST RADAR/SATELLITE/SURFACE DATA AND
LATEST MODEL GUIDANCE. IN ANY EVENT...FLIGHT CONDITIONS SHOULD
GENERALLY REMAIN VFR TO MVFR IN THE LIGHT TO MODERATE
RAIN...THOUGH BRIEF PERIODS OF LOWER CATEGORIES ARE POSSIBLE
SHOULD ANY HEAVIER SHOWERS OR THUNDER MOVE OVER A TERMINAL. THIS
WOULD BE MOST LIKELY TO OCCUR AT THE COASTAL SITES.
EAST WINDS WILL ALSO BE ON THE INCREASE AT THE COASTAL
SITES...THOUGH EXACTLY HOW HIGH THEY GET DEPENDS ON THE
TRACK/STRENGTH OF THE LOW.
&&
.PREV DISCUSSION... /ISSUED 447 AM CST FRI NOV 20 2009/
DISCUSSION...
RAPID WEATHER CHANGES IN PROGRESS AS GULF LOW TAKING SHAPE OFF
THE LOWER TEXAS COAST. ALTHOUGH MODELS REMAIN IN GENERAL AGREEMENT
ON EVOLUTION OF THIS WEATHER EVENT...TRACK OF SURFACE LOW REMAINS
SOMEWHAT UNCERTAIN WITH ECMWF FURTHEST NORTH AND NAM FURTHEST
SOUTH. WITH SURFACE LOW SETTING UP EAST OF CRP...A MIDDLE OF THE
ROAD SOLUTION TAKING THE LOW TOWARDS TERREBONE PARISH AND KEEPING
THE WARM SECTOR SOUTH OF OUR INLAND AREAS SEEMS MOST REASONABLE AT
THIS TIME. LATEST RADAR IMAGERY SHOWS A LARGE AREA OF SHOWERS AND
THUNDERSTORMS HAS DEVELOPED ACROSS MUCH OF COASTAL TEXAS...WITH
RAIN SHIELD NOW SPREADING INTO OUR SOUTHEAST TEXAS COUNTIES AND
COASTAL WATERS. HOWEVER...RAIN HAS RUN INTO AN ATMOSPHERIC BRICK
WALL AS CONSIDERABLE DRY AIR IN PLACE OVER OUR FORECAST AREA
EVAPORATES THE PRECIPITATION. HOWEVER...MODELS CONTINUE TO
INDICATE EVENTUAL MOISTENING OF THE AIRMASS WILL RESULT IN SHOWERS
AND THUNDERSTORMS SPREADING OVER THE FORECAST AREA FROM WEST TO
EAST DURING THE DAY INTO TONIGHT. HAVE ADJUSTED POPS BUT STILL
CALLING FOR HIGH PRECIP CHANCES ALONG AND SOUTH OF THE I-10
CORRIDOR...WITH BEST CHANCES IN THE COASTAL WATERS. LATEST HPC
GUIDANCE INDICATES RAINFALL TOTALS OF 1 TO 3 INCHES WILL BE
POSSIBLE IN SOUTHERN ZONES...MAINLY NEAR THE COAST...WITH LESS
THAN AN INCH EXPECTED IN NORTHERN ZONES.
WITH PRESSURE GRADIENT TIGHTENING BETWEEN THE GULF LOW AND HIGH
PRESSURE TO THE NORTHEAST...NUMEROUS WEATHER STATIONS ALONG THE
TEXAS COAST HAVE SEEN WIND GUSTS OF 25 TO 35 KNOTS ALREADY THIS
MORNING. AS THE GULF LOW APPROACHES OUR AREA THIS AFTERNOON AND
MOVES SOUTH OF OUR COASTLINE THIS EVENING...THE TIGHT PRESSURE
GRADIENT ON THE NORTH SIDE OF THE LOW MAY RESULT IN WINDS NEAR
LAKE WIND ADVISORY CRITERIA AS SHOWN BY THE GFS AND
ECMWF...ESPECIALLY NEAR THE COAST. THUS HAVE ISSUED A LAKE WIND
ADVISORY FOR COASTAL SOUTHEAST TEXAS AND PORTIONS OF SOUTHWEST
LOUISIANA...WITH STRONGEST WINDS MAINLY SOUTH OF THE HIGHWAY 73
AND HIGHWAY 14 CORRIDORS.
RAINFALL WILL COME TO AN END FROM WEST TO EAST ON SATURDAY AS GULF
LOW MOVES EAST OF THE REGION...WITH DRY WEATHER EXPECTED ON SUNDAY
AND MONDAY. GLOBAL MODELS CONTINUE TO INDICATE A COLD FRONT WILL
PUSH SOUTHWARD MONDAY NIGHT AND TUESDAY...BUT LIMITED MOISTURE
RETURN AHEAD OF THE BOUNDARY INDICATES ONLY SLIGHT CHANCE POPS
ARE WARRANTED AT THIS TIME.
MARINE...
SIGNIFICANT WEATHER IMPACTS EXPECTED ACROSS OUR COASTAL WATERS
TODAY AND TONIGHT AS GULF LOW STRENGTHENS AND MOVES NORTHEASTWARD
TOWARDS SOUTHEASTERN LOUISIANA. EASTERLY WINDS WILL RAPIDLY
STRENGTHEN TODAY AS A TIGHT PRESSURE GRADIENT DEVELOPS ON THE
NORTH SIDE OF THE LOW CENTER...WITH SUSTAINED WINDS AND GUSTS
NEAR GALE FORCE AT TIMES FROM THIS AFTERNOON THROUGH TONIGHT. IN
FACT...BUOY OBS AND EVEN INLAND STATIONS ALONG THE TEXAS COAST
HAVE ALREADY SEEN WINDS GUSTS AROUND 35 KNOTS THIS MORNING. WAVE
HEIGHTS CURRENTLY RUNNING AROUND 5 FEET AT BUOY 42035...AND ARE
EXPECTED TO CONTINUE TO INCREASE THROUGH THE DAY WITH WAVES UP TO
10 FEET TONIGHT IN THE OUTER WATERS. IN ADDITION...NUMEROUS
SHOWERS AND THUNDERSTORMS ARE ALREADY SPREADING ACROSS THE COASTAL
WATERS...AND SOME OF THESE COULD REACH STRONG TO SEVERE LEVELS.
TIDES ARE CURRENTLY RUNNING UP TO ONE FOOT ABOVE NORMAL. AS THE
EASTERLY WINDS INCREASE DURING THE DAY...TIDES BETWEEN ONE AND TWO
FEET ABOVE NORMAL WILL BE POSSIBLE ALONG OUR COASTLINE WHICH MAY
CAUSE SOME MINOR COASTAL FLOODING ISSUES THIS EVENING AT TIME OF
HIGH TIDE. UNCERTAINTY EXISTS ON HOW HIGH TIDES WILL GET AS WINDS
ARE EXPECTED TO BACK TO A MORE NORTHEASTERLY DIRECTION TONIGHT AS
THE LOW CENTER PASSES NEAR OR SOUTH OF THE COASTAL WATERS. THUS
AREAS AROUND VERMILION BAY MAY SEE MOST IMPACTS FROM ANY COASTAL
FLOODING THIS EVENING AS WINDS WILL REMAIN EASTERLY FOR A LONGER
PERIOD OF TIME VERSUS AREAS FURTHER WEST.
WINDS AND SEAS WILL SUBSIDE ON SATURDAY AS SYSTEM PUSHES EAST OF
OUR REGION...WITH OFFSHORE FLOW EXPECTED INTO SATURDAY NIGHT. ONSHORE
FLOW RETURNS ON SUNDAY AND MONDAY...WITH A COLD FRONT EXPECTED TO
PUSH SOUTHWARD THROUGH THE AREA ON TUESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 64 51 61 45 / 60 80 60 10
KBPT 64 51 61 46 / 90 80 50 10
KAEX 62 47 56 43 / 20 60 60 10
KLFT 65 51 61 45 / 20 80 80 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...LAKE WIND ADVISORY FROM NOON TODAY TO MIDNIGHT CST TONIGHT FOR
CALCASIEU-CAMERON-VERMILION.
COASTAL FLOOD ADVISORY FROM NOON TODAY TO 6 AM CST SATURDAY FOR
CALCASIEU-CAMERON-IBERIA-LOWER ST. MARTIN-ST. MARY-
VERMILION.
TX...LAKE WIND ADVISORY FROM NOON TODAY TO MIDNIGHT CST TONIGHT FOR
JEFFERSON-ORANGE.
COASTAL FLOOD ADVISORY FROM NOON TODAY TO 6 AM CST SATURDAY FOR
JEFFERSON-ORANGE.
GM...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM CST THIS EVENING
FOR COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO
INTRACOASTAL CITY, LA OUT 20 NM-WATERS FROM LOWER
ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA EXTENDING FROM
20 NM TO 60 NM.
GALE WARNING FROM 6 PM THIS EVENING TO 6 AM CST SATURDAY FOR
COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL
CITY, LA OUT 20 NM-WATERS FROM LOWER ATCHAFALAYA RIVER TO
INTRACOASTAL CITY, LA EXTENDING FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL NOON CST TODAY FOR COASTAL WATERS
FROM CAMERON, LA TO HIGH ISLAND, TX OUT 20 NM-COASTAL
WATERS FROM INTRACOASTAL CITY TO CAMERON, LA OUT 20 NM-
WATERS FROM CAMERON, LA TO HIGH ISLAND, TX EXTENDING FROM
20 NM TO 60 NM-WATERS FROM INTRACOASTAL CITY, LA TO
CAMERON, LA EXTENDING FROM 20 NM TO 60 NM.
GALE WARNING FROM NOON TODAY TO 6 AM CST SATURDAY FOR COASTAL
WATERS FROM CAMERON, LA TO HIGH ISLAND, TX OUT 20 NM-
COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON, LA OUT 20
NM-WATERS FROM CAMERON, LA TO HIGH ISLAND, TX EXTENDING
FROM 20 NM TO 60 NM-WATERS FROM INTRACOASTAL CITY, LA TO
CAMERON, LA EXTENDING FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 AM CST SATURDAY FOR
CALCASIEU LAKE-SABINE LAKE-VERMILION BAY.
&&
$$
PUBLIC/MARINE...05
AVIATION...13
000
FXUS64 KSHV 201132
AFDSHV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
532 AM CST FRI NOV 20 2009
.DISCUSSION...
EARLY THIS MORNING AN UPPER TROUGH ACROSS WESTERN OKLAHOMA...THE
LOWER PAN HANDLE REGION OF TEXAS AND INTO WEST TEXAS AND NORTHERN
MEXICO WAS PUSHING A SURFACE LOW AND TRAILING COLD FRONT ACROSS
NORTH CENTRAL TEXAS. PIECES OF ENERGY WERE ALSO EJECTING AROUND
THE BASE OF THE TROUGH AND OUT ACROSS THE WESTERN GULF AND
SOUTHEAST AND EAST TEXAS. ANOTHER SURFACE LOW OVER SOUTH TEXAS HAS
A WARM FRONT REACHING EAST INTO THE GULF OF MEXICO. HIGH PRESSURE
ON THE SURFACE ALONG THE MISSISSIPPI WAS PROVIDING A SOUTHEAST
FLOW THAT WAS PROVIDING MOISTURE AND CONTRIBUTING TO THE
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS OVER NORTH TEXAS FROM
NEAR THE DALLAS AREA NORTHEAST ALONG AND NEAR THE INTERSTATE 30
CORRIDOR THROUGH NORTHEAST TEXAS AND INTO SOUTHEAST OKLAHOMA AND
SOUTHWEST ARKANSAS...AND ALONG AND TO THE NORTHEAST OF THE
SURFACE LOW AND WARM FRONT NEAR THE TEXAS COAST. DURING THE DAY
TODAY AND INTO SATURDAY...THE UPPER TROUGH WILL BE MOVING EAST
SPREADING THE SHOWERS AND THUNDERSTORMS AHEAD OF THE SYSTEM AND
ITS ASSOCIATED SURFACE SYSTEMS. THE COLD FRONT MOVING ACROSS
NORTHERN TEXAS WILL BECOME NEARLY STATIONARY AND TRANSITION INTO
AN INVERTED TROUGH AS THE SURFACE LOW MOVES ALONG THE TEXAS COAST
AND NORTHERN GULF OF MEXICO. BY LATE SATURDAY THE UPPER LOW WILL BE
MOVING EAST OF THE MISSISSIPPI RIVER AND MOVING TOWARD THE
TENNESSEE VALLEY WITH THE SURFACE LOW APPROACHING SOUTH MISSISSIPPI.
RAINFALL WRAPPING AROUND THE THE BACK SIDE OF THE DEPARTING
SYSTEMS WILL BE ENDING ACROSS THE FOUR STATE REGION. HIGH PRESSURE
WILL BE BUILDING SOUTH. OUR NEXT COLD FRONT ARRIVES LATE MONDAY
NIGHT INTO TUESDAY AS AN UPPER TROUGH AMPLIFIES SOUTH ACROSS THE
CENTRAL SECTIONS OF THE COUNTRY. BY TUESDAY NIGHT THE RAIN
ASSOCIATED WITH THIS SYSTEM WILL BE COMING TO AN END WITH HIGH
PRESSURE BUILDING BACK ACROSS THE FORECAST AREA...KEEPING TEMPERATURES
ON THE COOL SIDE WITH DRY CONDITIONS THROUGH THE LATE HALF OF THE WORKWEEK.
/06/
&&
.AVIATION...
RADAR IMAGERY EARLY THIS MORNING SHOWS ISOLATED TO SCATTERED SHOWERS
WITH AN OCCASIONAL THUNDERSTORM HAVE DEVELOPED OVER NORTHWEST SECTIONS
OF THE FORECAST AREA. THIS ACTIVITY WILL GRADUALLY SPREAD ACROSS
THE ENTIRE AREA THROUGH THE REMAINDER OF THE MORNING AND INTO THE
DAYTIME HOURS...AFFECTING EASTERN LOCATIONS BY THIS AFTERNOON. VFR
FLIGHT CATEGORIES ARE SEEN AT ALL SITES THIS MORNING. HOWEVER A
FEW SITES MAY SEE PERIODS OF MVFR CATEGORIES BEFORE SUNRISE AS
CIGS MAY POSSIBLY DROP TO AROUND 2-3 KFT. CIGS WILL LIKELY LOWER
TO PREVAILING MVFR CONDITIONS AS WE MOVE INTO THE DAYTIME HOURS
WEST AND SPREAD EAST OVER THE REMAINDER OF THE FORECAST AREA AS WE
MOVE INTO THIS EVENING. CONDITIONS SHOULD BEGIN TO IMPROVE OVER
THE WEST WITH CIGS RISING BACK ABOVE MVFR CATEGORIES IN EAST TEXAS
SITES BY TONIGHT. ALL SITES WILL SEE THE POSSIBILITY OF HAVING
PERIODS OF IFR CONDITIONS IF AFFECTED BY AREAS OF HEAVIER RAIN
THROUGH THE FORECAST PERIOD. WINDS ARE EXPECTED TO REMAIN BETWEEN
5-10 KTS THROUGH THE FORECAST PERIOD. EAST WINDS TODAY SHOULD
BECOME MORE NORTHEAST BY THE END OF THE FORECAST PERIOD. VFR
CONDITIONS ARE EXPECTED TO RETURN BY SATURDAY THROUGH THE
REMAINDER OF THE WEEKEND. /22/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 61 47 60 43 68 / 50 60 60 30 0
MLU 63 47 58 46 65 / 30 70 70 40 0
DEQ 60 46 61 41 67 / 60 30 40 30 0
TXK 61 47 61 42 67 / 60 50 50 30 0
ELD 62 46 60 45 67 / 30 50 50 40 0
TYR 61 47 61 42 69 / 70 60 50 20 0
GGG 61 47 61 42 69 / 70 60 50 20 0
LFK 62 49 61 41 70 / 70 80 60 20 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
06/22
000
FXUS64 KLCH 201047
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
447 AM CST FRI NOV 20 2009
.DISCUSSION...
RAPID WEATHER CHANGES IN PROGRESS AS GULF LOW TAKING SHAPE OFF
THE LOWER TEXAS COAST. ALTHOUGH MODELS REMAIN IN GENERAL AGREEMENT
ON EVOLUTION OF THIS WEATHER EVENT...TRACK OF SURFACE LOW REMAINS
SOMEWHAT UNCERTAIN WITH ECMWF FURTHEST NORTH AND NAM FURTHEST
SOUTH. WITH SURFACE LOW SETTING UP EAST OF CRP...A MIDDLE OF THE
ROAD SOLUTION TAKING THE LOW TOWARDS TERREBONE PARISH AND KEEPING
THE WARM SECTOR SOUTH OF OUR INLAND AREAS SEEMS MOST REASONABLE AT
THIS TIME. LATEST RADAR IMAGERY SHOWS A LARGE AREA OF SHOWERS AND
THUNDERSTORMS HAS DEVELOPED ACROSS MUCH OF COASTAL TEXAS...WITH
RAIN SHIELD NOW SPREADING INTO OUR SOUTHEAST TEXAS COUNTIES AND
COASTAL WATERS. HOWEVER...RAIN HAS RUN INTO AN ATMOSPHERIC BRICK
WALL AS CONSIDERABLE DRY AIR IN PLACE OVER OUR FORECAST AREA
EVAPORATES THE PRECIPITATION. HOWEVER...MODELS CONTINUE TO
INDICATE EVENTUAL MOISTENING OF THE AIRMASS WILL RESULT IN SHOWERS
AND THUNDERSTORMS SPREADING OVER THE FORECAST AREA FROM WEST TO
EAST DURING THE DAY INTO TONIGHT. HAVE ADJUSTED POPS BUT STILL
CALLING FOR HIGH PRECIP CHANCES ALONG AND SOUTH OF THE I-10
CORRIDOR...WITH BEST CHANCES IN THE COASTAL WATERS. LATEST HPC
GUIDANCE INDICATES RAINFALL TOTALS OF 1 TO 3 INCHES WILL BE
POSSIBLE IN SOUTHERN ZONES...MAINLY NEAR THE COAST...WITH LESS
THAN AN INCH EXPECTED IN NORTHERN ZONES.
WITH PRESSURE GRADIENT TIGHTENING BETWEEN THE GULF LOW AND HIGH
PRESSURE TO THE NORTHEAST...NUMEROUS WEATHER STATIONS ALONG THE
TEXAS COAST HAVE SEEN WIND GUSTS OF 25 TO 35 KNOTS ALREADY THIS
MORNING. AS THE GULF LOW APPROACHES OUR AREA THIS AFTERNOON AND
MOVES SOUTH OF OUR COASTLINE THIS EVENING...THE TIGHT PRESSURE
GRADIENT ON THE NORTH SIDE OF THE LOW MAY RESULT IN WINDS NEAR
LAKE WIND ADVISORY CRITERIA AS SHOWN BY THE GFS AND
ECMWF...ESPECIALLY NEAR THE COAST. THUS HAVE ISSUED A LAKE WIND
ADVISORY FOR COASTAL SOUTHEAST TEXAS AND PORTIONS OF SOUTHWEST
LOUISIANA...WITH STRONGEST WINDS MAINLY SOUTH OF THE HIGHWAY 73
AND HIGHWAY 14 CORRIDORS.
RAINFALL WILL COME TO AN END FROM WEST TO EAST ON SATURDAY AS GULF
LOW MOVES EAST OF THE REGION...WITH DRY WEATHER EXPECTED ON SUNDAY
AND MONDAY. GLOBAL MODELS CONTINUE TO INDICATE A COLD FRONT WILL
PUSH SOUTHWARD MONDAY NIGHT AND TUESDAY...BUT LIMITED MOISTURE
RETURN AHEAD OF THE BOUNDARY INDICATES ONLY SLIGHT CHANCE POPS
ARE WARRANTED AT THIS TIME.
&&
.MARINE...
SIGNIFICANT WEATHER IMPACTS EXPECTED ACROSS OUR COASTAL WATERS
TODAY AND TONIGHT AS GULF LOW STRENGTHENS AND MOVES NORTHEASTWARD
TOWARDS SOUTHEASTERN LOUISIANA. EASTERLY WINDS WILL RAPIDLY
STRENGTHEN TODAY AS A TIGHT PRESSURE GRADIENT DEVELOPS ON THE
NORTH SIDE OF THE LOW CENTER...WITH SUSTAINED WINDS AND GUSTS
NEAR GALE FORCE AT TIMES FROM THIS AFTERNOON THROUGH TONIGHT. IN
FACT...BUOY OBS AND EVEN INLAND STATIONS ALONG THE TEXAS COAST
HAVE ALREADY SEEN WINDS GUSTS AROUND 35 KNOTS THIS MORNING. WAVE
HEIGHTS CURRENTLY RUNNING AROUND 5 FEET AT BUOY 42035...AND ARE
EXPECTED TO CONTINUE TO INCREASE THROUGH THE DAY WITH WAVES UP TO
10 FEET TONIGHT IN THE OUTER WATERS. IN ADDITION...NUMEROUS
SHOWERS AND THUNDERSTORMS ARE ALREADY SPREADING ACROSS THE COASTAL
WATERS...AND SOME OF THESE COULD REACH STRONG TO SEVERE LEVELS.
TIDES ARE CURRENTLY RUNNING UP TO ONE FOOT ABOVE NORMAL. AS THE
EASTERLY WINDS INCREASE DURING THE DAY...TIDES BETWEEN ONE AND TWO
FEET ABOVE NORMAL WILL BE POSSIBLE ALONG OUR COASTLINE WHICH MAY
CAUSE SOME MINOR COASTAL FLOODING ISSUES THIS EVENING AT TIME OF
HIGH TIDE. UNCERTAINTY EXISTS ON HOW HIGH TIDES WILL GET AS WINDS
ARE EXPECTED TO BACK TO A MORE NORTHEASTERLY DIRECTION TONIGHT AS
THE LOW CENTER PASSES NEAR OR SOUTH OF THE COASTAL WATERS. THUS
AREAS AROUND VERMILION BAY MAY SEE MOST IMPACTS FROM ANY COASTAL
FLOODING THIS EVENING AS WINDS WILL REMAIN EASTERLY FOR A LONGER
PERIOD OF TIME VERSUS AREAS FURTHER WEST.
WINDS AND SEAS WILL SUBSIDE ON SATURDAY AS SYSTEM PUSHES EAST OF
OUR REGION...WITH OFFSHORE FLOW EXPECTED INTO SATURDAY NIGHT. ONSHORE
FLOW RETURNS ON SUNDAY AND MONDAY...WITH A COLD FRONT EXPECTED TO
PUSH SOUTHWARD THROUGH THE AREA ON TUESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 64 51 61 45 69 / 60 80 60 10 0
KBPT 64 51 61 46 68 / 90 80 50 10 0
KAEX 62 47 56 43 66 / 20 60 60 10 0
KLFT 65 51 61 45 66 / 20 80 80 10 0
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...LAKE WIND ADVISORY FROM NOON TODAY TO MIDNIGHT CST TONIGHT FOR
THE FOLLOWING ZONES: CALCASIEU...CAMERON...VERMILION.
COASTAL FLOOD ADVISORY FROM NOON TODAY TO 6 AM CST SATURDAY FOR
THE FOLLOWING ZONES: CALCASIEU...CAMERON...IBERIA...LOWER
ST. MARTIN...ST. MARY...VERMILION.
TX...LAKE WIND ADVISORY FROM NOON TODAY TO MIDNIGHT CST TONIGHT FOR
THE FOLLOWING ZONES: JEFFERSON...ORANGE.
COASTAL FLOOD ADVISORY FROM NOON TODAY TO 6 AM CST SATURDAY FOR
THE FOLLOWING ZONES: JEFFERSON...ORANGE.
GM...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM CST THIS EVENING
FOR THE FOLLOWING ZONES: COASTAL WATERS FROM LOWER
ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA OUT 20 NM...
WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY,
LA EXTENDING FROM 20 NM TO 60 NM.
GALE WARNING FROM 6 PM THIS EVENING TO 6 AM CST SATURDAY FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM LOWER ATCHAFALAYA
RIVER TO INTRACOASTAL CITY, LA OUT 20 NM...WATERS FROM
LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA EXTENDING
FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM CAMERON, LA TO HIGH ISLAND, TX
OUT 20 NM...COASTAL WATERS FROM INTRACOASTAL CITY TO
CAMERON, LA OUT 20 NM...WATERS FROM CAMERON, LA TO HIGH
ISLAND, TX EXTENDING FROM 20 NM TO 60 NM...WATERS FROM
INTRACOASTAL CITY, LA TO CAMERON, LA EXTENDING FROM 20 NM
TO 60 NM.
GALE WARNING FROM NOON TODAY TO 6 AM CST SATURDAY FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM CAMERON, LA TO HIGH
ISLAND, TX OUT 20 NM...COASTAL WATERS FROM INTRACOASTAL
CITY TO CAMERON, LA OUT 20 NM...WATERS FROM CAMERON, LA TO
HIGH ISLAND, TX EXTENDING FROM 20 NM TO 60 NM...WATERS FROM
INTRACOASTAL CITY, LA TO CAMERON, LA EXTENDING FROM 20 NM
TO 60 NM.
SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 AM CST SATURDAY FOR
THE FOLLOWING ZONES: CALCASIEU LAKE...SABINE LAKE...
VERMILION BAY.
&&
$$
SHAMBURGER
000
FXUS64 KLIX 200958
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
358 AM CST FRI NOV 20 2009
.DISCUSSION...
LATEST SURFACE ANALYSIS CONTINUE TO SHOW A 1023MB HIGH OVER
TENNESSEE VALLEY AND AN INVERTED TROUGH FROM SOUTH TEXAS TO
CENTRAL OKLAHOMA. NORTHEAST FLOW WAS NOTED OVER NORTH CENTRAL AND
NORTHEAST GULF. UPPER AIR ANALYSIS SHOWED THE WAVE AXIS FROM THE
TEXAS PANHANDLE TO EL PASO REGION. IR SATELLITE IMAGERY SHOWED
CONVECTION ALONG THE TEXAS COAST AND FROM NORTH CENTRAL TEXAS TO
THE HILLS. INITIAL PLANER FIELDS REVEALED DECREASING THETA-E
VALUES WITH HEIGHT OVER THE WEST GULF AND MUCH OF TEXAS AHEAD OF
THE WAVE. ISOTACH ANALYSIS AT 250 REVEALED THE SOUTHERN STREAM OF
100 TO 110 KNOTS AT THE BASE AND BACK SIDE OF THE WAVE. ALL IN
ALL...AN ACTIVE 100 KNOT JET STREAM ACROSS MEXICO TO THE NORTH
GULF TO NORTH TEXAS. SHORT AND MID RANGE MODELS CONTINUE TO PUSH
THE WAVE EAST THROUGH THE NEXT 36 HOURS BECOMING NEGATIVELY TILTED
FROM ARKLATEX REGION TO THE FORECAST AREA BY SATURDAY AFTERNOON.
SURFACE LOW TRACK CONTINUES ACROSS THE SOUTH HALF OF FORECAST
AREA...GFS IS A LITTLE FASTER AROUND SATURDAY AFTERNOON WHILE
ECMWF TRACKS THE LOW ACROSS SATURDAY NIGHT. 00Z SOUNDING REVEAL A
STRONG INVERSION FROM 900 TO 800MB AND THAT INVERSION STAYS IN
PLACE THROUGH TONIGHT. THETA-E DECREASING WITH HEIGHT WILL EXIST
ABOVE THIS LAYER FOR SATURDAY. IN ADDITION...THE CLOSE PROXIMITY
OF THE UPPER LEVEL WAVE/LOW WITH A 500MB TEMPS -14 TO POSSIBLY
-18C ACROSS THE AREA WILL YIELD A LAPSE RATE SUPPORTING THUNDER.
HOWEVER...WE NEED SURFACE BASE TEMPS IN THE 70S AND THAT AIR MASS
WILL REMAIN SOUTH OF LAND AREAS SATURDAY...A FEW STRONG STORMS
MAY OCCUR ON COASTAL WATERS. WILL CARRY ISOLATED THUNDER SATURDAY
BUT MOST CONVECTION WILL REMAIN NEAR THE COAST SATURDAY. WILL SEE
SOME CLEARING SUNDAY. A SECOND SYSTEM WILL AFFECT THE AREA WITH A
SLIGHT CHANCE OF RAIN TUESDAY AND ANOTHER DRY SYSTEM FOR
THURSDAY...BOTH WILL KEEP TEMPS AT OR BELOW NORMS FOR NEXT WEEK.
&&
.AVIATION...
VFR CONDITIONS WILL BE THE RULE THROUGH 06Z SATURDAY...OTHER THAN
POSSIBLY A FEW HOURS OF MVFR VSBYS DUE TO HAZE OR LIGHT FOG AROUND
SUNRISE...ESPECIALLY AT KBTR. AS LOW MOVES FROM WESTERN GULF...WE
SHOULD GRADUALLY SEE THE COLUMN MOISTEN FROM THE TOP DOWN TONIGHT
WITH CEILINGS IN THE MVFR RANGE BY THE END OF THE PERIOD FOR THE
NEXT FORECAST PACKAGE...09Z-12Z SATURDAY AT KBTR...AND BEYOND THAT
FOR ALL OTHER TERMINALS. 35
&&
.MARINE...
MAIN CONCERN WILL BE WINDS SATURDAY. MODEL SOLUTIONS STILL RATHER
JUMPY AS FAR AS CONTINUITY GOES. WIND GRIDS WERE AGAIN BASED ON 00Z
ECMWF/NAM SOLUTIONS. 00Z GFS WAS AN OUTLIER DUE TO SPEED OF SYSTEM
MOVEMENT BEING MUCH QUICKER THAN OTHER MODELS. WIND SPEEDS ON GFS
ALSO APPEAR A LITTLE HIGHER THAN REALITY AT THIS POINT.
WE WILL NOT GET INTO EXERCISE CAUTION WIND SPEEDS UNTIL AFTER 06Z
SATURDAY...AND PROBABLY NOT INTO THE ADVISORY RANGE...MAINLY OVER
WESTERN WATERS...UNTIL MIDDAY ON SATURDAY. WILL HOLD OFF ON ANY
HEADLINES NOW...BUT EXPECT BY THE 21Z PACKAGE TODAY...ADVISORIES
WILL PROBABLY NEED RAISED. CONDITIONS SHOULD SETTLE DOWN PRETTY
QUICKLY SUNDAY. WINDS PROBABLY WILL REMAIN BELOW HEADLINE LEVELS FOR
SEVERAL DAYS AFTER THAT. 35
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 65 49 58 47 / 10 50 80 30
BTR 64 50 61 49 / 20 60 80 20
MSY 67 56 64 52 / 10 60 80 20
GPT 67 53 63 52 / 10 40 80 30
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
18/35
000
FXUS64 KLCH 200551
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
1151 PM CST THU NOV 19 2009
.DISCUSSION...
FOR 06Z TAF ISSUANCE.
&&
.AVIATION...
SATELLITE IMAGERY AND SFC OBS INDICATE VFR CONDITIONS ONGOING
ACROSS THE AREA ATTM WITH MAINLY HIGH CLOUDS STREAMING OVERHEAD.
LOOKING UPSTREAM REGIONAL 88D MOSAIC SHOWS AREA OF RAIN WITH
EMBEDDED THUNDER MOVING SLOWLY UP THE TEXAS COAST. OUTER FRINGE OF
THE RAIN SHIELD HAS HAD TROUBLE OVERCOMING DRIER AIR ALOFT WHICH
MAKES TIMING OF THE PRECIP INTO THE SWRN TERMINALS INTERESTING.
FOR THIS PACKAGE HAVE BROUGHT SOME RAINFALL INTO KBPT/KLCH BY LATE
MORNING WITH PREVAILING RAINFALL FOR THE AFTERNOON HOURS. ATTM
CEILINGS LOOK TO REMAIN ABOVE 3000 FEET UNTIL LATE AFTERNOON OR
EVENING AS DEVELOPING LOW CENTER OVER THE NWRN GULF APPROACHES AND
USHERS IN HEAVIER RAIN. OTHER PROBLEM AREA FOR AVIATION INTERESTS
FRIDAY WILL BE STRONG ERLY WINDS AT KBPT/KLCH WITH SPEEDS ABOVE 12
KNOTS AND GUSTS NEAR 20 KNOTS.
25
&&
.PREV DISCUSSION... /ISSUED 902 PM CST THU NOV 19 2009/
UPDATE...THE COASTAL STORM IS BEGINNING TO GET ITS ACT TOGETHER
AROUND CORPUS CHRISTI WHERE COOLING CLOUD TOPS AND LIGHTNING ARE
SIGNALING A RAPID INTENSIFICATION. WILL ADD SOME THUNDER TO THE
LOWER SE TX AND WESTERN WATERS LATE TNITE TO THE SCATTERED SHOWERS
IN THE FCST. WILL ALSO ADD MENTION OF ISOLD SHOWERS FOR SW LA AS
WELL AS INTERIOR SE TX AND WESTERN PORTIONS OF CEN LA BY DAYBREAK.
EARLIER CLOUDS AND HIGHER DEW POINTS THAN PROGGED SO TWEAKED
OVERNIGHT TEMPS UP AS WELL. GALE WARNING LOOKING WARRENTED AS MSAS
ALREADY SHOWING SUSTAINED 25 TO 30 KNOTS TO THE SW OF OUR WATERS.
UPDATED GRIDS FOR THE COASTAL WATERS WILL SHOW GALES INITIATING BY
16Z OR 10L ON FRIDAY.
SWEENEY
PREV DISCUSSION... /ISSUED 328 PM CST THU NOV 19 2009/
SYNOPSIS...
A STATIONARY FRONT MARKS THE SOUTHWEST PERIPHERY OF A DOME OF
HIGH PRESSURE ACROSS NORTHERN MISSISSIPPI. THE FRONTAL SURFACE
DRAPES ACROSS THE SOUTH CENTRAL GULF OF MEXICO...BEFORE SWINGING
NORTHWEST TO A FRONTAL WAVE NEAR PALACIOS.
THE SOUTHWEST-PERIPHERY FRONTAL SURFACE SEPARATES HIGHLY STABLE AIR
POLEWARD FROM UNSTABLE AIR EQUATORWARD.
FURTHER-UP...A SOUTHERN-STREAM DIFLUENT WESTERLY TROUGH WILL ADVANCE
THROUGH WEST TEXAS LATER THIS EVENING. MIDLATITUDE PACIFIC SHORTWAVES
ARE TRAVELING AROUND THE PERIPHERY OF THE TROUGH...UNDERGOING AN
EXTENSIVE...EQUATORWARD...OVER-MOUNTAIN TOP FETCH.
THE SHORTWAVES TRAVEL EQUATORWARD THROUGH THE ROCKIES...EXITING THE
FRONT RANGE OF THE SIERRA MADRE OCCIDENTAL...BEFORE CONTINUING THEIR
NORTHEAST TRAVELS ACROSS THE LOWER TEXAS COASTAL PLAINS.
CONSEQUENTLY...THESE EXITING SHORTWAVES CONTAIN A GREAT DEAL OF
STRETCHING VORTICITY (OR LEESIDE CYCLOGENESIS).
THE PALACIOS FRONTAL WAVE WILL RAPIDLY-DEEPEN AS THE ENERGETIC
SHORTWAVES PASS OVERHEAD. THE EVOLVING GULF CYCLONE WILL TRAVEL EAST
-NORTHEAST ACROSS THE LOUISIANA COASTAL WATERS...MAKING LANDFALL
NEAR MARSH ISLAND AROUND NOON SATURDAY.
DISCUSSION...
FOR TONIGHT...THE WARM CONVEYOR BELT AIRSTREAM SLOWLY EVOLVES INTO A
COOL-CONVEYOR BELT AIR STREAM...AS PRESSURES BEGIN FALLING VICINITY
PALACIOS. SHOWERS WILL ENTER THE GOLDEN TRIANGLE FROM THE SOUTHWEST
AFTER MIDNIGHT. THE OVERNIGHT MINIMUMS WILL BE RUNNING SLIGHTLY
ABOVE NORMAL.
FOR FRIDAY...THE COOL-CONVEYOR BELT AIRSTREAM ACROSS THE WESTERN
UPPER GULF COAST STATES EVOLVES INTO A TROWAL AIRSTREAM...AS THE
PALACIOS LOW ENTERS INTO THE UPPER TEXAS COASTAL WATERS. THE
CONSEQUENT AND STEADY CYCLONIC-UPSLIDING AIR OVER THE NORTHEAST
QUADRANT OF LOW WILL GENERATE AND MAINTAIN A LARGE RAIN SHIELD.
PASSING VERY-ENERGETIC SHORTWAVES ALOFT WILL SET OFF SCATTERED
SHOWERS AND THUNDERSTORMS WHICH WILL MAINLY BE CONFINED OVER THE
COASTAL WATERS.
AT PRESENT BELIEVE THAT THE PRIMARY THREATS WITH THIS EVOLVING LOW
REMAINS OVER THE COASTAL WATERS...GALE WARNING.
MINOR COASTAL FLOODING IS ALSO POSSIBLE...BUT DUE TO THE UNCERTAINTY
OF THE FORECAST TRACK AND INTENSITY...HAVE ERRORED ON THE SIDE OF
CAUTION...AND ISSUED A COASTAL FLOOD WATCH.
TRARES
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 54 66 51 59 48 / 10 40 80 60 10
KBPT 56 66 52 58 47 / 40 50 80 50 10
KAEX 46 67 48 57 47 / 0 10 70 60 10
KLFT 49 67 51 60 48 / 0 20 80 60 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...COASTAL FLOOD WATCH FROM FRIDAY EVENING THROUGH LATE FRIDAY
NIGHT FOR THE FOLLOWING ZONES: CALCASIEU...CAMERON.
COASTAL FLOOD WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY
MORNING FOR THE FOLLOWING ZONES: IBERIA...LOWER ST.
MARTIN...ST. MARY...VERMILION.
TX...COASTAL FLOOD WATCH FROM FRIDAY EVENING THROUGH LATE FRIDAY
NIGHT FOR THE FOLLOWING ZONES: JEFFERSON...ORANGE.
GM...SMALL CRAFT ADVISORY FROM 6 AM TO NOON CST FRIDAY FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM LOWER ATCHAFALAYA
RIVER TO INTRACOASTAL CITY, LA OUT 20 NM...WATERS FROM
LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA EXTENDING
FROM 20 NM TO 60 NM.
GALE WARNING FROM NOON FRIDAY TO 6 AM CST SATURDAY FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM LOWER ATCHAFALAYA
RIVER TO INTRACOASTAL CITY, LA OUT 20 NM...WATERS FROM
LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA EXTENDING
FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 6 AM CST FRIDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM CAMERON, LA TO HIGH ISLAND, TX
OUT 20 NM...COASTAL WATERS FROM INTRACOASTAL CITY TO
CAMERON, LA OUT 20 NM...WATERS FROM CAMERON, LA TO HIGH
ISLAND, TX EXTENDING FROM 20 NM TO 60 NM...WATERS FROM
INTRACOASTAL CITY, LA TO CAMERON, LA EXTENDING FROM 20 NM
TO 60 NM.
GALE WARNING FROM 6 AM FRIDAY TO MIDNIGHT CST FRIDAY NIGHT FOR
THE FOLLOWING ZONES: COASTAL WATERS FROM CAMERON, LA TO
HIGH ISLAND, TX OUT 20 NM...COASTAL WATERS FROM
INTRACOASTAL CITY TO CAMERON, LA OUT 20 NM...WATERS FROM
CAMERON, LA TO HIGH ISLAND, TX EXTENDING FROM 20 NM TO 60
NM...WATERS FROM INTRACOASTAL CITY, LA TO CAMERON, LA
EXTENDING FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING
ZONES: CALCASIEU LAKE...SABINE LAKE.
&&
$$
000
FXUS64 KLIX 200535
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1135 PM CST THU NOV 19 2009
.AVIATION...
VFR CONDITIONS WILL PREVAIL FOR THE BALANCE OF THE TAF FORECAST
PERIOD. HOWEVER...SOME MVFR CONDITIONS DUE TO LIGHT FOG WILL BE
POSSIBLE AT TIMES AT EACH OF THE TAF SITES BETWEEN 08Z AND 14Z.
INCREASING HIGH AND THEN MID LEVEL CLOUDINESS WILL BE OBSERVED
DURING THE DAY FRIDAY. THE FIRST CHANCE FOR SHOWERS WILL BE IN THE
OFFING FRIDAY EVENING AFTER 03Z AT KBTR...KMCB...AND KMSY. 11
&&
.PREV DISCUSSION... /ISSUED 737 PM CST THU NOV 19 2009/
UPDATE...
..SOUNDING DISCUSSION...
NO PROBLEMS WITH THE FLIGHT THIS EVENING. ANOTHER DRY AND STABLE
EVENING WITH A PW OF 0.72 INCHES AND AN LI OF 10.8. A BROKEN DECK
OF ALTO CUMULUS CLOUDS EVIDENT AROUND TEN THOUSAND FEET WHERE DEW
POINT DEPRESSIONS ARE AROUND ZERO DEGREES. WINDS ARE LIGHT AND
VARIABLE NEAR THE SURFACE AND MODERATE AND WESTERLY ALOFT.
PREV DISCUSSION... /ISSUED 320 PM CST THU NOV 19 2009/
SHORT TERM...
MILD CONDITIONS TO CONTINUE ONE MORE DAY WITH A GRADUAL INCREASE
IN LOW LEVEL MOISTURE TO IMPART WARMER TEMPERATURES NEXT 24 HOURS
OR SO. MODELS CONTINUE TO SHOW CONSENSUS ON DEVELOPING A WEST GULF
LOW PRESSURE SYSTEM FRIDAY AS UPPER LEVEL TROUGH ADVANCES IN SOUTHERN
BRANCH FLOW ACROSS TEXAS TOWARDS THE WEST GULF. MODELS DO DIFFER
SOMEWHAT ON TRACK THROUGH FORECAST AREA WITH SOME SUGGESTING THE
CENTER OF CIRCULATION MOVING ONSHORE AND PLACING THE MISSISIPPI
COUNTIES AND LOWER SOUTHEAST LOUISIANA PARISHES BRIEFLY IN THE
WARM SECTOR...WHILE OTHERS CONTINUE TO KEEP LAND AREAS ON THE
COOLER SIDE OF THE LOW. WILL MAINTAIN CONTINUITY OF FORECAST WITH
TRACK JUST ALONG THE COAST OR ACROSS THE NEAR COASTAL WATERS. BULK
OF SENSIBLE WEATHER SHOULD TAKE PLACE AFTER MIDNIGHT FRIDAY
THROUGH ABOUT NOON SATURDAY WITH THUNDER LIMITED TO MARINE AREAS
AND PERHAPS THE NEAR COASTAL PARISHES. MODELS HAVE SEEMED TO
SOFTEN THE GRADIENT SOMEWHAT AHEAD OF THE SYSTEM BUT AN INCREASE
TO MODERATE EASTERLY FLOW IS EXPECTED FOR SOME DURATION FRIDAY
NIGHT AND EARLY SATURDAY. SEVERE WEATHER NOT ANTICIPATED OVER LAND
AREAS THOUGH MARINE ZONES MAY EXPERIENCE SQUALL LINE ACTIVITY IN
ADVANCE OF THE LOW`S PASSAGE. THERE WILL BE A SURGE COMPONENT TO
TIDES WITH THE GREATER RUN-UP LIKELY TO TAKE PLACE DURING THE
ASTRONOMICAL LOW TIDES. NO COASTAL FLOOD STATEMENTS WILL BE ISSUED
DUE TO EXPECTED MINIMAL IMPACTS BUT AN INCREASE IN WATERS LEVELS
MAY BE NOTED THROUGH SATURDAY LATE MORNING/EARLY AFTERNOON BEFORE
RETURNING TO NORMAL LEVELS SATURDAY NIGHT.
LONG TERM...
SEASONABLY NICE WEATHER IS ANTICIPATED IN THE UPCOMING WEEK
INCLUDING THANKSGIVING DAY WITH SLIGHTLY ABOVE NORMAL TEMPERATURES
AND LOW RAIN CHANCES EXPECTED EACH DAY. THE WEAK UPPER TROUGH
PASSAGE FOR TUESDAY APPEARS TO SWING THROUGH WITH THE MOISTURE
DIVERGING UPON ARRIVAL TO MAKE THE PASSAGE A RELATIVELY DRY ONE.
MARINE...
A GRADUAL INCREASE IN EASTERLY WINDS AND SEAS EXPECTED
NEXT 24 HOURS WITH A MORE NOTICEABLE INCREASE LATE FRIDAY THROUGH
SATURDAY MORNING AS WEST GULF LOW DEVELOPS AND MATURES. WINDS AND
SEAS SHOULD ABATE RATHER QUICKLY AS THE GRADIENT COLLAPSES WITH
THE SYSTEM`S PASSAGE WITH IMPROVING CONDITIONS EXPECTED LATE
SATURDAY THROUGH SUNDAY. HIGH PRESSURE BECOMING ESTABLISHED OVER
THE MID- GULF STATES SHOULD MAINTAIN LOW WINDS AND SEAS THROUGH
MUCH OF NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 67 42 66 49 / 0 0 0 50
BTR 68 46 68 50 / 0 0 0 50
MSY 69 50 68 53 / 0 0 0 50
GPT 67 45 68 53 / 0 0 0 40
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
000
FXUS64 KSHV 200415
AFDSHV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
1015 PM CST THU NOV 19 2009
...AN UPDATE TO THE FORECAST WILL BE COMING...
.DISCUSSION...
THE WEATHER MAPS THIS EVENING ARE QUITE MESSY.
FIRST OFF...
WATER VAPOR IMAGERY SHOWS A DEEPENING SHORTWAVE TROUGH HEADING INTO
WEST TEXAS. AS THIS FEATURE HEADS EASTWARD...A SOUTHWESTERLY FLOW
ALOFT SHOULD ALLOW PERTURBATIONS TO TRAVERSE THE FORECAST AREA
OVERNIGHT AND INTO FRIDAY.
THEN...
THERE IS THE COMPLEX FRONTAL SYSTEM...WHICH IS GRADUALLY BEING
PUSHED EASTWARD ACROSS TEXAS BY THE SHORTWAVE TROUGH. I HAVE A
PSEUDO-WARM FRONT SUBJECTIVELY ANALYZED SOMEWHERE BETWEEN HOUSTON
AND CORPUS CHRISTI. THE WARM FRONT WILL TRY ITS BEST TO LIFT
NORTHWARD INTO DEEP EAST TEXAS OVERNIGHT...BUT PROBABLY WILL NOT
MAKE IT. SHOWERS AND THUNDERSTORMS HAVE ALREADY DEVELOPED ACROSS
THE COASTAL BEND...AND ARE SLOWLY WORKING THEIR WAY INTO SOUTHEAST
TEXAS.
ALSO...
WE HAVE A WEAK AREA OF SURFACE HIGH PRESSURE...CENTERED JUST NORTH
OF BIRMINGHAM ALABAMA. WINDS FLOWING AROUND THE HIGH ARE KEEPING
DEWPOINTS ON THE LOW SIDE ACROSS OUR EASTERN COUNTIES AND PARISHES.
IN ALL HONESTLY...IT DOES NOT LOOK LIKE MOISTURE WILL MAKE A
SIGNIFICANT COMEBACK TO THIS PART OF THE FORECAST AREA UNTIL FRIDAY
MORNING.
PUTTING IT ALL TOGETHER...
USING THE LATEST AVAILABLE 4KM WRF AND OBSERVED TRENDS...I EXPECT
CONVECTION TO GRADUALLY INCREASE ACROSS EAST TEXAS OVERNIGHT. IT
LOOKS LIKE GREATEST ODDS WILL COME AFTER 3 AM AND INCREASE AFTER 6
AM. BASED ON WHAT I AM SEEING...I HAVE MODIFIED SHOWER/THUNDERSTORM
PROBABILITIES OVERNIGHT...BASICALLY KEEPING THE GREATEST ODDS OVER
EAST TEXAS.
CLOUD COVER WILL ALSO SLOWLY INCREASE OVERNIGHT...AND LOWS MAY NOT
DROP AS FAR AS PREVIOUSLY EXPECTED /ESPECIALLY/ OVER EAST TEXAS.
THIS ADJUSTMENT HAS ALSO BEEN MADE...ALONG WITH A FEW TWEAKS TO THE
HOURLY TEMPERATURE AND DEWPOINT GRIDS.
ISC GRIDS HAVE BEEN SENT AND SHOULD BE POSTED TO THE INTERNET. AN
UPDATED SUITE OF TEXT PRODUCTS WILL BE ISSUED SHORTLY. /21/
&&
.AVIATION...
VFR FLIGHT CONDITIONS CONTINUE FOR ALL TERMINALS THROUGH THIS
EVENING AND INTO THE WEE HOURS. SHOWERS AND THUNDERSTORMS SOUTH OF
KATT AND OUT OVER THE COASTAL BEND ARE MOVING THIS WAY AT 15/20 KTS
AND WILL BE ARRIVING KLFK/KTYR BEFORE DAYBREAK. EXPECT MVFR WITH IT
OVERSPREADING OUR CWA BY 18Z WITH SOME IFR IN AREAS OF HEAVY
RAINFALL. IMPROVEMENTS WILL DEVELOP LATE FROM SW TO NE AS SFC WINDS
BACK FROM SE TO E AM...AND ON TO NE DURING LATE PM GENERALLY LESS
THAN 10 KTS. VFR EXPECTED THIS WEEKEND. /24/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 51 62 49 60 45 / 20 40 60 50 30
MLU 42 65 47 59 47 / 0 30 50 70 40
DEQ 53 61 46 62 40 / 20 50 40 40 30
TXK 54 61 47 61 45 / 20 40 50 50 30
ELD 47 63 47 61 45 / 10 20 40 60 40
TYR 56 59 49 63 45 / 40 70 70 40 20
GGG 55 59 49 61 43 / 30 70 70 40 20
LFK 57 62 49 61 42 / 30 70 70 40 20
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
PUBLIC FORECASTER... D. BUTTS
AVIATION FORECASTER... CHATELAIN
000
FXUS64 KLCH 200302
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
902 PM CST THU NOV 19 2009
.UPDATE...THE COASTAL STORM IS BEGINNING TO GET ITS ACT TOGETHER
AROUND CORPUS CHRISTI WHERE COOLING CLOUD TOPS AND LIGHTNING ARE
SIGNALING A RAPID INTENSIFICATION. WILL ADD SOME THUNDER TO THE
LOWER SE TX AND WESTERN WATERS LATE TNITE TO THE SCATTERED SHOWERS
IN THE FCST. WILL ALSO ADD MENTION OF ISOLD SHOWERS FOR SW LA AS
WELL AS INTERIOR SE TX AND WESTERN PORTIONS OF CEN LA BY DAYBREAK.
EARLIER CLOUDS AND HIGHER DEW POINTS THAN PROGGED SO TWEAKED
OVERNIGHT TEMPS UP AS WELL. GALE WARNING LOOKING WARRENTED AS MSAS
ALREADY SHOWING SUSTAINED 25 TO 30 KNOTS TO THE SW OF OUR WATERS.
UPDATED GRIDS FOR THE COASTAL WATERS WILL SHOW GALES INITIATING BY
16Z OR 10L ON FRIDAY.
SWEENEY
&&
.PREV DISCUSSION... /ISSUED 328 PM CST THU NOV 19 2009/
SYNOPSIS...
A STATIONARY FRONT MARKS THE SOUTHWEST PERIPHERY OF A DOME OF
HIGH PRESSURE ACROSS NORTHERN MISSISSIPPI. THE FRONTAL SURFACE
DRAPES ACROSS THE SOUTH CENTRAL GULF OF MEXICO...BEFORE SWINGING
NORTHWEST TO A FRONTAL WAVE NEAR PALACIOS.
THE SOUTHWEST-PERIPHERY FRONTAL SURFACE SEPARATES HIGHLY STABLE AIR
POLEWARD FROM UNSTABLE AIR EQUATORWARD.
FURTHER-UP...A SOUTHERN-STREAM DIFLUENT WESTERLY TROUGH WILL ADVANCE
THROUGH WEST TEXAS LATER THIS EVENING. MIDLATITUDE PACIFIC SHORTWAVES
ARE TRAVELING AROUND THE PERIPHERY OF THE TROUGH...UNDERGOING AN
EXTENSIVE...EQUATORWARD...OVER-MOUNTAIN TOP FETCH.
THE SHORTWAVES TRAVEL EQUATORWARD THROUGH THE ROCKIES...EXITING THE
FRONT RANGE OF THE SIERRA MADRE OCCIDENTAL...BEFORE CONTINUING THEIR
NORTHEAST TRAVELS ACROSS THE LOWER TEXAS COASTAL PLAINS.
CONSEQUENTLY...THESE EXITING SHORTWAVES CONTAIN A GREAT DEAL OF
STRETCHING VORTICITY (OR LEESIDE CYCLOGENESIS).
THE PALACIOS FRONTAL WAVE WILL RAPIDLY-DEEPEN AS THE ENERGETIC
SHORTWAVES PASS OVERHEAD. THE EVOLVING GULF CYCLONE WILL TRAVEL EAST
-NORTHEAST ACROSS THE LOUISIANA COASTAL WATERS...MAKING LANDFALL
NEAR MARSH ISLAND AROUND NOON SATURDAY.
DISCUSSION...
FOR TONIGHT...THE WARM CONVEYOR BELT AIRSTREAM SLOWLY EVOLVES INTO A
COOL-CONVEYOR BELT AIR STREAM...AS PRESSURES BEGIN FALLING VICINITY
PALACIOS. SHOWERS WILL ENTER THE GOLDEN TRIANGLE FROM THE SOUTHWEST
AFTER MIDNIGHT. THE OVERNIGHT MINIMUMS WILL BE RUNNING SLIGHTLY
ABOVE NORMAL.
FOR FRIDAY...THE COOL-CONVEYOR BELT AIRSTREAM ACROSS THE WESTERN
UPPER GULF COAST STATES EVOLVES INTO A TROWAL AIRSTREAM...AS THE
PALACIOS LOW ENTERS INTO THE UPPER TEXAS COASTAL WATERS. THE
CONSEQUENT AND STEADY CYCLONIC-UPSLIDING AIR OVER THE NORTHEAST
QUADRANT OF LOW WILL GENERATE AND MAINTAIN A LARGE RAIN SHIELD.
PASSING VERY-ENERGETIC SHORTWAVES ALOFT WILL SET OFF SCATTERED
SHOWERS AND THUNDERSTORMS WHICH WILL MAINLY BE CONFINED OVER THE
COASTAL WATERS.
AT PRESENT BELIEVE THAT THE PRIMARY THREATS WITH THIS EVOLVING LOW
REMAINS OVER THE COASTAL WATERS...GALE WARNING.
MINOR COASTAL FLOODING IS ALSO POSSIBLE...BUT DUE TO THE UNCERTAINTY
OF THE FORECAST TRACK AND INTENSITY...HAVE ERRORED ON THE SIDE OF
CAUTION...AND ISSUED A COASTAL FLOOD WATCH.
TRARES
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 54 66 51 59 48 / 10 40 80 60 10
KBPT 56 66 52 58 47 / 40 50 80 50 10
KAEX 46 67 48 57 47 / 0 10 70 60 10
KLFT 49 67 51 60 48 / 0 20 80 60 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...COASTAL FLOOD WATCH FROM FRIDAY EVENING THROUGH LATE FRIDAY
NIGHT FOR THE FOLLOWING ZONES: CALCASIEU...CAMERON.
COASTAL FLOOD WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY
MORNING FOR THE FOLLOWING ZONES: IBERIA...LOWER ST.
MARTIN...ST. MARY...VERMILION.
TX...COASTAL FLOOD WATCH FROM FRIDAY EVENING THROUGH LATE FRIDAY
NIGHT FOR THE FOLLOWING ZONES: JEFFERSON...ORANGE.
GM...SMALL CRAFT ADVISORY FROM 6 AM TO NOON CST FRIDAY FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM LOWER ATCHAFALAYA
RIVER TO INTRACOASTAL CITY, LA OUT 20 NM...WATERS FROM
LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA EXTENDING
FROM 20 NM TO 60 NM.
GALE WARNING FROM NOON FRIDAY TO 6 AM CST SATURDAY FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM LOWER ATCHAFALAYA
RIVER TO INTRACOASTAL CITY, LA OUT 20 NM...WATERS FROM
LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA EXTENDING
FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST FRIDAY
FOR THE FOLLOWING ZONES: COASTAL WATERS FROM CAMERON, LA TO
HIGH ISLAND, TX OUT 20 NM...COASTAL WATERS FROM
INTRACOASTAL CITY TO CAMERON, LA OUT 20 NM...WATERS FROM
CAMERON, LA TO HIGH ISLAND, TX EXTENDING FROM 20 NM TO 60
NM...WATERS FROM INTRACOASTAL CITY, LA TO CAMERON, LA
EXTENDING FROM 20 NM TO 60 NM.
GALE WARNING FROM 6 AM FRIDAY TO MIDNIGHT CST FRIDAY NIGHT FOR
THE FOLLOWING ZONES: COASTAL WATERS FROM CAMERON, LA TO
HIGH ISLAND, TX OUT 20 NM...COASTAL WATERS FROM
INTRACOASTAL CITY TO CAMERON, LA OUT 20 NM...WATERS FROM
CAMERON, LA TO HIGH ISLAND, TX EXTENDING FROM 20 NM TO 60
NM...WATERS FROM INTRACOASTAL CITY, LA TO CAMERON, LA
EXTENDING FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST SATURDAY
FOR THE FOLLOWING ZONES: CALCASIEU LAKE...SABINE LAKE.
&&
$$
000
FXUS64 KLIX 200137
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
737 PM CST THU NOV 19 2009
.UPDATE...
...SOUNDING DISCUSSION...
NO PROBLEMS WITH THE FLIGHT THIS EVENING. ANOTHER DRY AND STABLE
EVENING WITH A PW OF 0.72 INCHES AND AN LI OF 10.8. A BROKEN DECK
OF ALTO CUMULUS CLOUDS EVIDENT AROUND TEN THOUSAND FEET WHERE DEW
POINT DEPRESSIONS ARE AROUND ZERO DEGREES. WINDS ARE LIGHT AND
VARIABLE NEAR THE SURFACE AND MODERATE AND WESTERLY ALOFT.
&&
.PREV DISCUSSION... /ISSUED 320 PM CST THU NOV 19 2009/
SHORT TERM...
MILD CONDITIONS TO CONTINUE ONE MORE DAY WITH A GRADUAL INCREASE
IN LOW LEVEL MOISTURE TO IMPART WARMER TEMPERATURES NEXT 24 HOURS
OR SO. MODELS CONTINUE TO SHOW CONSENSUS ON DEVELOPING A WEST GULF
LOW PRESSURE SYSTEM FRIDAY AS UPPER LEVEL TROUGH ADVANCES IN SOUTHERN
BRANCH FLOW ACROSS TEXAS TOWARDS THE WEST GULF. MODELS DO DIFFER
SOMEWHAT ON TRACK THROUGH FORECAST AREA WITH SOME SUGGESTING THE
CENTER OF CIRCULATION MOVING ONSHORE AND PLACING THE MISSISIPPI
COUNTIES AND LOWER SOUTHEAST LOUISIANA PARISHES BRIEFLY IN THE
WARM SECTOR...WHILE OTHERS CONTINUE TO KEEP LAND AREAS ON THE
COOLER SIDE OF THE LOW. WILL MAINTAIN CONTINUITY OF FORECAST WITH
TRACK JUST ALONG THE COAST OR ACROSS THE NEAR COASTAL WATERS. BULK
OF SENSIBLE WEATHER SHOULD TAKE PLACE AFTER MIDNIGHT FRIDAY
THROUGH ABOUT NOON SATURDAY WITH THUNDER LIMITED TO MARINE AREAS
AND PERHAPS THE NEAR COASTAL PARISHES. MODELS HAVE SEEMED TO
SOFTEN THE GRADIENT SOMEWHAT AHEAD OF THE SYSTEM BUT AN INCREASE
TO MODERATE EASTERLY FLOW IS EXPECTED FOR SOME DURATION FRIDAY
NIGHT AND EARLY SATURDAY. SEVERE WEATHER NOT ANTICIPATED OVER LAND
AREAS THOUGH MARINE ZONES MAY EXPERIENCE SQUALL LINE ACTIVITY IN
ADVANCE OF THE LOW`S PASSAGE. THERE WILL BE A SURGE COMPONENT TO
TIDES WITH THE GREATER RUN-UP LIKELY TO TAKE PLACE DURING THE
ASTRONOMICAL LOW TIDES. NO COASTAL FLOOD STATEMENTS WILL BE ISSUED
DUE TO EXPECTED MINIMAL IMPACTS BUT AN INCREASE IN WATERS LEVELS
MAY BE NOTED THROUGH SATURDAY LATE MORNING/EARLY AFTERNOON BEFORE
RETURNING TO NORMAL LEVELS SATURDAY NIGHT.
LONG TERM...
SEASONABLY NICE WEATHER IS ANTICIPATED IN THE UPCOMING WEEK
INCLUDING THANKSGIVING DAY WITH SLIGHTLY ABOVE NORMAL TEMPERATURES
AND LOW RAIN CHANCES EXPECTED EACH DAY. THE WEAK UPPER TROUGH
PASSAGE FOR TUESDAY APPEARS TO SWING THROUGH WITH THE MOISTURE
DIVERGING UPON ARRIVAL TO MAKE THE PASSAGE A RELATIVELY DRY ONE.
AVIATION...
VFR CAVOK CONDITIONS THROUGH 18Z FRIDAY WITH A STEADY ADVANCE OF
LOW CLOUDS IN THE MVFR RANGE SCT-BKN 020-030 MAINLY AFTER 18Z.
RAIN MAY ONSET CLOSER TO 21/03Z AT KBTR AND KMCB BUT BEYOND THE 24
HOURS OF THIS TAF PACKAGE ISSUANCE.
MARINE....
A GRADUAL INCREASE IN EASTERLY WINDS AND SEAS EXPECTED NEXT 24
HOURS WITH A MORE NOTICEABLE INCREASE LATE FRIDAY THROUGH SATURDAY
MORNING AS WEST GULF LOW DEVELOPS AND MATURES. WINDS AND SEAS
SHOULD ABATE RATHER QUICKLY AS THE GRADIENT COLLAPSES WITH THE
SYSTEM`S PASSAGE WITH IMPROVING CONDITIONS EXPECTED LATE SATURDAY
THROUGH SUNDAY. HIGH PRESSURE BECOMING ESTABLISHED OVER THE MID-
GULF STATES SHOULD MAINTAIN LOW WINDS AND SEAS THROUGH MUCH OF
NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 42 66 49 55 / 0 0 50 80
BTR 46 68 50 57 / 0 0 50 80
MSY 50 68 53 63 / 0 0 50 80
GPT 45 68 53 64 / 0 0 40 80
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
000
FXUS64 KSHV 192228
AFDSHV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
428 PM CST THU NOV 19 2009
.DISCUSSION...
HIGH PRESSURE ON THE SURFACE TO THE EAST AND SURFACE LOW PRESSURE OVER
WEST TEXAS CONTINUED TO PULL GULF MOISTURE NORTH ACROSS TEXAS AND
INT0 THE PLAINS. SOME OF THIS MOISTURE RIDING OVER THE COOLER
SURFACE TEMPERATURES ALONG WITH WEAK DISTURBANCES MOVING OVERHEAD
WILL START RAIN PRODUCTION DURING THE NIGHT TONIGHT FOR PARTS OF
EAST TEXAS AND SOUTHEAST OKLAHOMA WITH THE PRECIPITATION EXPANDING
EAST INTO NORTHWEST LOUISIANA AND PARTS OF SOUTHWEST ARKANSAS LATE.
WATER VAPOR LOOP THIS AFTERNOON SHOWED AN UPPER LOW CLOSING OFF
OVER NEW MEXICO AND WEST TEXAS AND MOVING EAST THROUGH TEXAS AND MEXICO
ON FRIDAY PUSHING A COLD FRONT ACROSS WEST TEXAS WITH ANOTHER
SURFACE LOW LIFTING OUT OF MEXICO INTO SOUTH TEXAS. THIS LOW WILL
HAVE A WARM FRONT REACHING SOUTHEAST INTO THE GULF AND THE
INVERTED TROUGH REACHING NORTH ACROSS CENTRAL TEXAS AND CENTRAL OKLAHOMA.
BY FRIDAY NIGHT THE UPPER LOW WILL BE PUSHING ACROSS TEXAS AND OKLAHOMA
WITH THE SURFACE LOW MOVING ACROSS THE NORTHERN GULF. BY TAKING
THE MORE SOUTHERN ROUTE...THE BETTER CHANCE OF SHOWERS AND THUNDERSTORMS
WILL BE JUST INLAND OF THE COAST AND GENERALLY SOUTH OF THE
INTERSTATE CORRIDOR AND WILL CARRY THE THUNDER AS ISOLATED FOR NOW.
THE HIGHER CHANCES OF RAIN WILL ALSO BE GENERALLY SOUTH OF THE
INTERSTATE 20 CORRIDOR. THE UPPER LOW WILL BE MOVING SLOWLY EAST
OVER THE FOUR STATE REGION DURING THE DAY SATURDAY RAIN CONTINUING
TO WARP AROUND THE BACK SIDE OF THE SURFACE LOW MOVING ACROSS THE
EASTERN GULF AND AROUND THE UPPER LOW AND ON THE EASTERN SIDE. THE
RAINS WILL BE COMING TO AN END FROM WEST TO EAST LATE SATURDAY
NIGHT AND EARLY ON SUNDAY. SURFACE HIGH PRESSURE WILL BE MOVING
OVER THE FORECAST AREA WITH A NEARLY ZONAL FLOW ALOFT FOR SUNDAY
INTO MONDAY WHEN THE NEXT TROUGH SPREADS ACROSS THE CENTRAL
SECTIONS OF THE COUNTRY. WITH THIS NEXT TROUGH WE WILL BE
EXPECTING A COLD FRONT DROPPING THE OVERNIGHT LOWS BACK INTO THE
30S AND 40S FOR THE MID WEEK TIME FRAME AS HIGH PRESSURE ALOFT AND
ON THE SURFACE AFFECT THE WEATHER PATTERN INTO LATE WEEK. LONG
RANGE MODEL OUTPUT HINTS AT THE NEXT RAIN CHANCE RETURNS DURING
THE WEEKEND AFTER THANKSGIVING. /06/
&&
.AVIATION...
VFR FLIGHT CONDITIONS WILL PREVAIL FOR ALL TERMINALS THROUGH THE
FORECAST EVENING. SOME CLOUDS IN THE 3KFT TO 5KFT RANGE MOVING INTO
THE WESTERN SITES WILL OVERSPREAD THE REGION BY MORNING. WESTERN
SITES SHOULD BEGIN SEEING LIGHT RAIN CHANCES INCREASE AHEAD OF OUR
NEXT APPROACHING SYSTEM. WINDS ARE EXPECTED TO GENERALLY BE OUT OF
THE SOUTH TO SOUTHEAST AT AROUND 5-10 KTS THROUGH THE FORECAST
PERIOD. /04/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 50 62 49 60 45 / 20 40 60 50 30
MLU 42 65 47 59 47 / 10 30 50 70 40
DEQ 48 61 46 62 40 / 20 50 40 40 30
TXK 50 61 47 61 45 / 20 40 50 50 30
ELD 44 63 47 61 45 / 10 20 40 60 40
TYR 54 59 49 63 45 / 40 70 70 40 20
GGG 52 59 49 61 43 / 40 70 70 40 20
LFK 54 62 49 61 42 / 40 70 70 40 20
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
06/04
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