[top]
000
FXUS63 KLSX 222152
AFDLSX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
352 PM CST SUN NOV 22 2009
.DISCUSSION...
/336 PM CST SUN NOV 22 2009/
ABOVE NORMAL TEMPERATURES HAVE ONCE AGAIN BEEN THE RULE ACROSS THE
AREA TODAY. THIS IS THANKS TO WEAK RIDGING AND A RELATIVELY CLOUD
FREE AFTERNOON AS THE MID CLOUDS WHICH BLANKETED CENTRAL SECTIONS
THIS MORNING HAVE SHUNTED BACK TO THE WEST. A COUPLE OF ITEMS OF
INTEREST TONIGHT AND THEY ARE THE LEAD SHORT WAVE MOVING THROUGH
THE PLAINS ATTM AND THE LOW CLOUDS BLANKETING THE LOWER MS VLY AND
DIXIE REGIONS. THIS SHORTWV IS FORECAST TO WEAKEN AND MOVE INTO
THE MIDDLE MS VLY TONIGHT ACCOMPANIED BY WEAK ASCENT AND A
RESURGENCE OF THE MID LEVEL MOISTURE TO THE NORTHEAST. I AM NOT
OVERLY EXCITED ABOUT THE PCPN PROSPECTS...BUT WAA AND THE MID
CLOUDS/MOISTURE IN WRN MO MANAGED TO RESULT IN SOME LIGHT PCPN
THIS MORNING. SO I THINK ITS PRUDENT TO KEEP SOME SLIGHT CHANCE
POPS IN FAR NRN SECTIONS. AS FAR AS THE STRATUS WELL TO THE
SOUTH...THE MODELS...SPCLY THE GFS IN VERY BULLISH ADVECTING THESE
CLOUDS NWD TONIGHT AND INTO THE REGION AS THE LOW LEVEL FLOW
VEERS. ALL THE MODELS PRETTY MUCH SHOW A GOOD DEAL OF RH CENTERED
IN THE 925-850 MB LAYER ON MONDAY...SUGGESTIVE OF QUITE A BIT OF
STRATUS OR SRATOCU. I STUCK PRETTY CLOSE TO THE WARMER MET MOS BUT
IF SKIES ARE SOLID OVERCAST...THEN THE COOLER MAV WILL PROBABLY BE
MORE CORRECT.
THE BIGGEST ITEM OF INTEREST IS THE MID/UPPER LOW FCST TO DEVELOP
ACROSS THE NORTHERN ROCKIES TONIGHT AND PROGRESS INTO THE MID MS
VLY BY TUES EVENING...AND THEN INTO THE LOWER GREAT LAKES ON WED
MORNING. THE MODELS DO AGREE ON DIGGING AND INTENSIFICATION OF
THIS SYSTEM AND SLOWING THIS DOWN...BUT STILL SHOW SOME VARIANCES ON PSN
OF THE LOW AND THEREFORE THE PROGRESSION OF THE ATTENDANT COLD
FRONT AND PCPN. INTERESTINGLY THE NEW 18Z NAM IS SUPPORTIVE OF THE
SLOWER AND FURTHEST SOUTH PSN OFFERED BY THE UKMET. THIS FCST IS
MORE OF A ENSEMBLE APPROACH WITH AN ANTICIPATED UPPER LOW PSN IN
NORTH CENTRAL MO AT 00Z WED AND THE ATTENDANT COLD FRONT DRAPPED
INVOF OF THE MS RIVER. GIVEN THE DIGG AND CLOSED NATURE...THE
SLOWER SOLNS CERTAINLY HAVE SOME MERIT. STILL HAVE SOME POPS INTO
CENTRAL MO ON MONDAY NIGHT...BUT TUESDAY APPEARS TO BE THE WET
PERIOD. THIS IS A POTENT SYSTEM WITH GOOD DEEP LARGE SCALE LIFT
SUPPORTIVE OF A GOOD BAND OF RAIN. CROSS SECTIONS ALSO DEPICT A
SHALLOW UNSTABLE LAYER ALOFT CENTERED ABOVE 650 MB. GIVEN THE
STRONG ASCENT THIS COULD RESULT IN A FEW LIGHTING STRIKES/RUMBLES
BUT I BELIEVE THE PROBABILITY IS TOO LOW TO MENTION ATTM. LOTS OF
CLOUDS AND CAA IN THE WAKE OF THE CDFNT ON TUESDAY NIGHT AND INTO
WEDNESDAY...WITH A STRONGER DIGG NW FLOW TROF/LOW BRINGING AN
EVEN COLDER SURGE OF AIR INTO THE AREA FOR THANKSGIVING INTO
FRIDAY. WILL HAVE TO WATCH ANY LIGHT PCPN POTENTIAL WITH THIS
LATER WAVE...TOO MUCH UNCERTAINTY IN THE TRACK DETAILS TO GET
EXCITED AT THIS TIME.
GLASS
&&
.AVIATION...
/1054 AM CST SUN NOV 22 2009/
FOR THE 18Z TAFS...ERN EDGE OF MID LVL CLOUDS OVER THE NWRN HALF
OF MO CONTINUE TO ERODE LATE THIS MRNG. COU WILL LIKELY LOSE THERE
10000 FT CEILING EARLY THIS AFTN. OTHERWISE JUST SOME CIRRUS CLOUDS
STREAMING NWD INTO STL/SUS N OF MID LVL LOW OVER NRN AL. MID-HI
LEVEL CLOUDS WILL LIKELY ADVECT BACK INTO THE TAF SITES TGT AS
A SHRTWV TROF OVER THE PLAINS MOVES EWD THRU NRN MO. MORE
SIGNIFICANT WILL BE THE LOW LEVEL CLOUD COVER...MOISTURE OVER THE
SERN US WHICH THE MODELS ADVECT NWD INTO THE TAF SITES BY EARLY
MON MRNG. WILL PUT A BKN025 CEILING IN THE TAFS BEGINNING AT
12-14Z MON. THE CEILING SHOULD GRADUALLY RISE INTO THE VFR
CATAGORY DURING THE AFTN ON MON BASED ON THE MODEL MOS CIG HGT
GUIDANCE. THERE ALSO MAY BE SOME LIGHT FOG LATE TGT AND MON MRNG
...AROUND 4-6SM BR BESIDES THE LOW LEVEL CLOUDINESS. THE E-SELY
SFC WNDS WILL CONTINUE THIS AFTN. IT APPEARS THAT THE MOS WIND
GUIDANCE IS A TAD TOO LGT AT 17Z SUN...WITH UIN AND COU OBS
REPORTING 12-13 KT SUSTAINED WNDS. THE SFC WNDS WILL WEAKEN THIS
EVNG THEN PICK UP AGAIN FROM A SELY DIRECTION BY LATE MON MRNG.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
[top]
000
FXUS63 KEAX 222127
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
327 PM CST SUN NOV 22 2009
.DISCUSSION...
PRECIP CHCS DURING THE EARLY PORTION OF THE WEEK ALONG WITH THE
EVOLUTION OF SFC TEMPS ASSOCIATED WITH THIS SYSTEM WILL REMAIN THE
ITEMS OF MOST CONCERN FOR THIS FCST.
THIS AFTN...PROFILER AND WV IMAGERY CONFIRM THE PRESENCE OF A RATHER
FAST MOVING UPR S/W TROUGH RACING THROUGH CENTRAL KANSAS ATTM. THIS
S/W TROUGH IS HANDLED WELL BY THE DETERMINISTIC MODEL
GUIDANCE...WITH THE UPR TROUGH AXIS CROSSING THE MO/KS STATE LINE
AROUND MIDNIGHT. WITHOUT A LARGE QUANTITY OF LOW-LVL MOISTURE FOR
THIS SYSTEM EXPECT THE IMPACT TO BE MINIMAL. ISENTROPIC LIFT
REMAINS RATHER UNFOCUSED IN NATURE...BUT MAY BE STRONG ENOUGH TO TAP
INTO THICKER MID-LVL MOISTURE PLUME AHEAD OF THE S/W IN THE NORTHERN
AND EASTERN CWA. WILL MAINTAIN SLIGHT CHC POP.
OF OTHER CONCERN IN THE IMMEDIATE SHORT TERM WILL BE THE POTENTIAL
FOR PATCHY DENSE FOG ACROSS THE NORTHERN PORTIONS OF THE CWA. MODELS
SUGGEST THE DEVELOPMENT OF A WEAK SURFACE WARM FRONT ACROSS THE
CENTRAL CWA BY MID-MORNING. BOUNDARY LAYER MOISTURE IS EXPECTED TO
REMAIN RATHER HIGH OVERNIGHT. HOWEVER THE AMOUNT OF CLEARING AND
MID-LVL SUBSIDENCE BEHIND THE UPR S/W REMAIN IN DOUBT.
SOUNDINGS...NUMERICAL GUIDANCE...AND SREF PROBABILITIES SUGGEST AT
LEAST MVFR FOG WITH PATCHY DENSE FOG POSSIBLE SHOULD SKIES CLEAR
MORE THAN CURRENTLY ANTICIPATED.
FOR MONDAY...NEXT UPR WAVE CURRENTLY IN THE PAC NW EXPECTED TO DIG
ACROSS THE WESTERN PLAINS BY MON AFTN AND QUICKLY PIVOT NE INTO THE
GREAT LAKES BY TUE NIGHT. 12Z DETERMINISTIC MODELS REMAIN IN GENERAL
AGREEMENT...WITH THE GFS SLIGHTLY FASTER AND DEEPER THAN THE 12Z NAM
AND ECMWF. THE 18Z NAM IS A DISTANT OUTLIER...WITH A SOLN THAT IS
DIGGING THE UPR TROUGH TO FAR TO THE SOUTH GIVEN THE AMPLITUDE OF THE
KICKER WAVE UPSTREAM. NEVERTHELESS...IT SHOULD BE NOTED THAT THERE
HAS BEEN A SLIGHTLY SLOWER AND FURTHER SOUTH TREND IN DETERMINISTIC
GUIDANCE DURING THE PAST 2 MODEL RUNS AND THESE TRENDS HAVE BEEN
CONSIDERED IN THE CURRENT FCST GIVEN THE STRONG PAC JET ACCOMPANYING
THIS SYSTEM. ENSEMBLES REMAIN SUPPORTIVE OF THE 12Z GFS/ECMWF SOLNS
KEEPING THE OVERALL UPR TRACK ACROSS CENTRAL KS ACROSS NORTHERN MO.
OVERALL EXPECTING A FAIRLY DRY AND WARM DAY ON MON AS WE REMAIN
STUCK IN MID-LVL S/W RIDGING BETWEEN UPR TROUGHS. WILL CONTINUE TO
ADVERTISE LOW 60S FOR TEMPS ALONG WITH A SLIGHT CHC POP IN THE NW
CORNER.
FOR MON NIGHT AND TUE...BIGGEST QUESTIONS ARISE TO JUST HOW FAST
THIS UPR TROUGH WILL EJECT EASTWARD. BY MON EVE STRONG UPR SUPPORT
BEGINS TO MOVE NE INTO THE AREA AS THE SYSTEM REACHES PEAK INTENSITY.
HOWEVER THE TILT AND INTENSITY OF THIS SYSTEM REMAIN KEY TO THE
FCST...WITH CURRENT INDICATIONS OF THIS SYSTEM APPROACHING THE CWA IN
A POSITIVE TILT AND PIVOTING OVER THE WESTERN CWA MON NIGHT. IN
RETURN THIS MAY FORCE TWO DIFFERENT AREAS OF PRECIP...AN AREA OF RAIN
IN NORTHEAST QUADRANT OF THE UPR LOW SUPPORTED BY PV ADVECTION AND
THE UPR JET IN NORTHERN KS AND NW MO...AND A SECONDARY AREA OF PRECIP
FURTHER SSW OVER SE KS AND SOUTHERN MO. ADDITIONALLY...POINT
SOUNDINGS AND PLAN VIEW FCST MAPS SUGGEST A RAPID PERIOD OF LOW-LVL
WAA AND THETA-E ADVECTION ENHANCING THE 850-600 MB LAPSE RATES ENOUGH
TO INDUCE ISOLATED TO SCT CONVECTION AS THE PRIMARY BAND MOVES
THOUGH.
DEPENDING ON THE TRACK OF THE UPR LOW...SIGNIFICANT DRY SLOT IS
EXPECTED TO ROTATE INTO THE AREA LATE MON NIGHT OR EARLY TUE FORCING
LINEAR AREA OF PRECIP QUICKLY OUT OF THE ARE BY 12Z TUE. MOISTURE IS
EXPECTED TO WRAP AROUND THE UPR LOW AS A EXTENSIVE TROWAL
DEVELOPS...THIS MOISTURE MAY DEVELOP INTO ADDITIONAL PRECIP TUE AFTN
AND NIGHT.
FROZEN PRECIP CHCS STILL REMAIN VERY LOW WITH THIS SYSTEM DESPITE
THE SLIGHTLY DEEPER TRACKS AS SUGGESTED BY GUIDANCE. NO COLD AIR WILL
BE PRESENT PRIOR TO THIS SYSTEMS ARRIVAL...AND EVEN DYNAMICAL
COOLING PROCESSES WON`T BE ABLE TO OVERTAKE THE LOW-LVL WARM AIR
PRESENT PRIOR TO THE ARRIVAL. I WON`T RULE A RA/SN MIXTURE OUT IN THE
WRAP AROUND TROWAL TUE AFTN...ESPECIALLY IF SOME OF THE COLDER LOW-
LVL AIR CAN BE TAPPED OFF THE WESTERN PLAINS. HOWEVER FEEL GIVEN THE
TIMING OF ARRIVAL AND THE FACT THAT THE SYSTEM WILL BE NEARLY
VERTICALLY STACKED DOESN`T BODE WELL.
FCST LOW AND HIGH TEMPS WILL BE A BIG CONCERN MON NIGHT AND TUE. A
SLIGHTLY SLOW SYSTEM WILL KEEP SFC TEMPS WELL INTO THE UPR 40S TO
PERHAPS LOW 50S MON NIGHT. HIGHS ON TUE WILL BE DICTATED BY THE
SPEED OF THE SFC FRONT AND COLDER AIR WRAPPING IN FROM THE SW. HAVE
ISSUED A NON-STANDARD DIURNAL CURVE...AND BUMPED UP MON NIGHT
READINGS AND LOWERED TUESDAYS TEMPS.
MD
MEDIUM RANGE (WEDNESDAY THROUGH SUNDAY)...
BY THE MIDDLE OF THE UPCOMING WORK WEEK THE CENTRAL PLAINS WILL BE
UNDER THE INFLUENCE OF A NORTHWEST FLOW ON THE BACKSIDE OF A SYSTEM
THAT WILL HAVE PASSED THROUGH THE PLAINS EARLIER IN THE WEEK. MID
RANGE MODELS FROM THE ECMWF TO GFS AND GEM...PLUS MANY OF THE
ENSEMBLE MEMBERS...HAVE ALL COME IN LINE WITH EACH OTHER OVER THE
PAST SEVERAL RUNS...SO SYNOPTIC SCALE FEATURES ARE IN DECENT
AGREEMENT.
SHORTWAVE WILL DESCEND THROUGH THE NORTHWEST FLOW WEDNESDAY AND
THURSDAY HELPING RELOAD/SLOW THE TROUGH THAT WILL BE MOVING EAST
ACROSS THE CONUS MID-WEEK. RESULT WILL BE THAT TEMPERATURES SHOULD
BE A BIT COOLER THAN OUR GOING FORECAST NUMBERS...WITH NORMAL TO
BELOW NORMAL READINGS EXPECTED THROUGH FRIDAY. FOR THE WEEKEND THE
SLOWER TROUGH PROGRESSION IMPLIES THAT THE WEEKEND WARM UP...WITH
THE RIDGE FOLLOWING THE TROUGH...COULD BE MUTED A BIT WITH
TEMPERATURES BARELY ABLE TO CLIMB ABOVE SEASONALLY NORMAL VALUES.
HAVE ADJUSTED TEMPERATURES TO REFLECT THIS TREND...WITH NEW NUMBERS
NEAREST THE MEX GUIDANCE VALUES.
OTHERWISE...AS FOR PRECIPITATION...EVEN WITH THE TROUGH SLOWING
EXPECTATIONS ARE THAT THE SHORTWAVE IN THE NORTHWEST FLOW WILL BE
TRAVERSING THE REGION FROM THE NORTHERN PLAINS INTO THE OHIO RIVER
VALLEY RATHER QUICKLY WEDNESDAY AND THURSDAY. THIS SHOULD LIMIT THE
POTENTIAL FOR ANY PRECIPITATION IN THE FORECAST AREA MID WEEK TO
REGIONS OF NORTH CENTRAL AND NORTHEAST MISSOURI. EVEN THEN...
THOUGHTS ARE THAT SLIGHT CHANCE POPS ARE ALL THAT ARE WARRANTED AT
THIS TIME GIVEN MOISTURE CONCERNS AND TIMING. FOR THE WEEKEND...THE
RIDGE THAT WILL BE MOVING IN SHOULD KEEP CONDITIONS DRY.
CUTTER
&&
.AVIATION...
FOR THE 18Z TAFS...VFR CONDITIONS ARE EXPECTED TO REMAIN IN PLACE
THROUGH THE DAYTIME HOURS AS WELL AS INTO THE EVENING. S/W TROUGH
CONTINUES TO RACE EASTWARD ACROSS WESTERN AND CENTRAL KS THIS
AFTN...WITH BROAD ISENTROPIC LIFT GENERATING LIGHT SHRA/SPRINKLES
NORTH OF THE TERMINALS. IN ADDITION...MODEST LOW-LVL THETA-E
ADVECTION HAS RESULTED IN A BAND OF MVFR/IFR STRATUS ACROSS CENTRAL
KS ALONG A STATIONARY FRONT AND SFC LOW.
THIS S/W WILL LIFT NE THROUGH THE TERMINALS OVERNIGHT
TONIGHT...HOWEVER ISENTROPIC LIFT DOES NOT LOOK STRONG ENOUGH TO
PRODUCE ANYTHING MORE THAN SPRINKLES...WITH HIGHER POPS NORTH OF
KSTJ. HOWEVER...LATER SHIFTS WILL NEED TO KEEP AN EYE ON MVFR/IFR
CIGS TO OUR WEST WITH ARE PROGGED TO LIFT NORTHWARD ALONG A
DEVELOPING SFC WARM FRONT BY 3 AM. THIS FRONT SHOULD SLOWLY LIFT
NORTHWARD AFTER DAYBREAK AND MAY PRODUCE A 4 TO 6 HOUR SPAN OF MVFR
TO PERHAPS EVEN IFR CIGS...WITH INCREASING BOUNDARY LAYER MOISTURE
TRAPPED ALONG THIS FRONT ALSO REDUCING VIS INTO MVFR TO PERHAPS IFR
CATEGORIES. WILL INCLUDE A TEMPO GROUP FOR THIS OCCURRENCE...WITH
REDUCED VISIBILITIES MORE PREVALENT AT KSTJ WHERE LOW-LVL ISENTROPIC LIFT
WILL BE THE GREATEST. AS UPR S/W LIFTS NE BY MID-MORNING A RETURN TO
VFR CONDITIONS WOULD BE LIKELY.
DUX
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
[top]
000
FXUS63 KSGF 222118
AFDSGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
318 PM CST SUN NOV 22 2009
.DISCUSSION...
A CHANGE IN THE LARGE SCALE PATTERN WILL COMMENCE THIS WEEK WITH A
RATHER PROGRESSIVE REGIME BECOMING AMPLIFIED BY THE END OF THE
WEEK. THE MAIN FORECAST FOCUS CONTINUES TO BE ON A STORM SYSTEM
EXPECTED TO IMPACT THE AREA DURING THE LATE MONDAY AND TUESDAY
TIME FRAME. THIS WILL LIKELY BE OUR BEST SHOT AT PRECIPITATION
OVER THE NEXT SEVEN DAYS. FOCUS WAS THEN ON TEMPERATURES TOWARDS
THE END OF THE WEEK AS A COLD CANADIAN AIRMASS SEEPS INTO THE
REGION.
TONIGHT AND MONDAY...A WEAK UPPER LEVEL WAVE WILL SHUNT EAST
ACROSS THE REGION. MOST OF THE LIFT ASSOCIATED WITH THIS FEATURE
WILL PASS NORTH OF THE OZARKS. THE BIGGEST IMPACT IT WILL HAVE IS
CLOUD COVER. MODEL CROSS SECTIONS INDICATE A DECENT AMOUNT OF LOW
AND MID LEVEL MOISTURE. THEREFORE THINK CLOUDS WILL REMAIN
ABUNDANT...WHICH WILL HAVE A SIGNIFICANT IMPACT ON TEMPERATURES.
WENT ON THE WARM SIDE OF GUIDANCE TONIGHT...WHILE GOING COOLER FOR
MONDAY. ALL IN ALL...THE MAV SEEMS TO HAVE THE BEST HANDLE ON THIS.
MONDAY NIGHT AND TUESDAY...UPPER LEVEL ENERGY WILL DIG SOUTHEAST
INTO THE CENTRAL PLAINS. MEANWHILE...SURFACE LOW PRESSURE WILL
DEVELOP AND TRACK NORTHEAST ACROSS THE SOUTHERN AND EVENTUALLY
CENTRAL PLAINS. A COLD FRONT WILL TRAIL THE LOW AND PASS THROUGH
THE AREA FROM LATE MONDAY NIGHT INTO TUESDAY. WE WILL LIKELY SEE A
LINE OR BROKEN LINE OF FORCED SHOWERS WITH THIS FRONT. KEPT A
SLIGHT CHANCE FOR THUNDER IN THE FORECAST GIVEN THE JET DYNAMICS
WITH THIS SYSTEM...BUT INSTABILITY WILL BE VERY LIMITED. COULD SEE
SOME LIGHT WRAP AROUND PRECIPITATION CREEP INTO CENTRAL MISSOURI
LATE IN THE DAY ON TUESDAY. TEMPERATURES WILL BE TRICKY ON
TUESDAY WITH CLOUD COVER AND COLD AIR ADVECTION. WINDS WILL
ACTUALLY BEING DOWNSLOPE IN NATURE...BUT STILL THINK ALL FORMS OF
MOS GUIDANCE LOOK TOO WARM. THEREFORE UNDERCUT THE COOLER MAV BY A
CATEGORY.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...A SECOND UPPER LEVEL WAVE
WILL STRONGLY DIG OUT OF THE CANADIAN PRAIRIES TOWARDS THE MIDDLE
MISSISSIPPI VALLEY. THIS WAVE WILL BRING A STRONGER COLD FRONT
ACROSS THE REGION...WITH GLOBAL MODELS STILL ADVERTISING 850 MB
TEMPERATURES PLUNGING INTO THE -6 YO -9 DEGREE CELSIUS RANGE BY
THURSDAY MORNING. VERY LITTLE MOISTURE TO WORK WITH HERE...WITH
THE BULK OF THE PRECIPITATION REMAINING ACROSS THE GREAT LAKES
REGION. STUCK FAIRLY CLOSE TO MEX GUIDANCE AHEAD OF THE FRONT ON
WEDNESDAY...BUT UNDERCUT WEDNESDAY NIGHT AS STRONG COLD AIR
ADVECTION COMMENCES.
END OF THE WEEK...LONG WAVE CHARTS CONTINUE TO INDICATE A BLOCKING
SIGNAL SETTING UP ACROSS THE EASTERN PACIFIC. WITH A MORE
AMPLIFIED PATTERN IN PLACE...THINK THIS CANADIAN AIRMASS WILL BE
SLOW TO EXIT THE REGION. THANKSGIVING LOOKS DOWNRIGHT CHILLY AS IT
IS QUITE POSSIBLE WE SEE ABUNDANT CLOUD COVER IN A CYCLONIC
NORTHWEST FLOW. HAVE GONE WITH LOW TO MID 40S FOR HIGHS...AND
THIS MAY STILL BE TOO WARM. PROSPECTS ARE INCREASING FOR A
WIDESPREAD HARD FREEZE THURSDAY NIGHT...AND POSSIBLY AGAIN FRIDAY
NIGHT ACROSS CENTRAL MISSOURI. DESPITE A LARGE SCALE NORTHWEST
FLOW PERSISTING...WE SHOULD FINALLY SEE SOME MODERATION IN
TEMPERATURES EARLY NEXT WEEKEND.
SCHAUMANN
&&
.AVIATION...
FOR THE 18Z KSGF...KJLN AND KBBG TAFS...VFR CONDITIONS WILL BE THE
RULE FOR THE REST OF THIS AFTERNOON AND THIS EVENING. AS SOUTHERLY
WINDS AND A SCATTERED TO BROKEN MID LEVEL CLOUD DECK PREVAILS OVER
THE TAF SITES. TONIGHT AN UPPER LEVEL DISTURBANCES WILL PUSH
THROUGH AREA. AS A RESULT AN AREA OF LOW LEVEL CLOUDS WILL DEVELOP
AND SPREAD INTO THE REGION...RESULTING IN MVFR CEILINGS. CANNOT
RULE OUT IFR CEILINGS TUESDAY MORNING...BUT AT THIS TIME
CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE IN THIS TAF PACKAGE.
WISE
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KLSX 221754
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1154 AM CST SUN NOV 22 2009
.DISCUSSION...
/438 AM CST SUN NOV 22 2009/
LITTLE CHANGE TO THE GOING FORECAST FOR THIS CYCLE. THE PRIMARY
FOCUS CONTINUES TO BE THE STORM FOR TUESDAY WHICH WILL BRING SOME
RAIN AND COOLER TEMPERATURES TO THE REGION. HOWEVER...FIRST IN LINE
IS A WEAK SHORTWAVE THAT WILL BRING CLOUDS AND PERHAPS SOME
SPRINKLES TO PARTS OF CENTRAL AND NORTHEAST MISSOURI AND WEST
CENTRAL ILLINOIS TODAY. RH PROGS ARE PRETTY PESSIMISTIC FOR ANY
CLEARING TODAY OVER CENTRAL MISSOURI SO HAVE KEPT CLOUDY/MOSTLY
CLOUDY CONDITIONS IN THE FORECAST. IT`S DEBATABLE WHETHER OR NOT TO
INCLUDE ANY POPS OR MENTION OF PRECIP AT ALL TODAY. SOUNDINGS SHOW
A VERY DRY LAYER AROUND 900 MB WITH DEWPOINT DEPRESSIONS OF NEARLY
30 DEGREES. WILL KEEP AN EYE ON THE RADAR AND SURFACE OBSERVATIONS
THIS MORNING AND UPDATE AS NECESSARY...BUT IF THOSE SOUNDINGS ARE
CORRECT ANYTHING SHORT OF A HEAVY THUNDERSTORM WILL HAVE TROUBLE
PRECIPITATING THROUGH THAT DRY LAYER. HAVE INTRODUCED SOME SLIGHT
CHANCE POPS FOR TONIGHT THO AS THE MAIN SHORTWAVE RIPPLES BY. LOW
LEVELS STILL LOOK PRETTY DRY...BUT THERE COULD BE ENOUGH ISENTROPIC
LIFT COUPLED WITH SHORTWAVE ENERGY TO KICK OUT A FEW LIGHT RAIN
SHOWERS.
THE MAIN SHOW WILL BEGIN EARLY TUESDAY MORNING AS A STRONG WAVES
DROPS OFF THE ROCKIES AND CLOSES OFF OVER THE PLAINS. LATEST
GUIDANCE APPEARS TO BE A BIT SLOWER THAN PREVIOUS FORECASTS WITH
RESPECT TO THE SURFACE FEATURES ASSOCIATED WITH THIS SYSTEM. HAVE
ACCORDINGLY SLOWED THE PROGRESSION OF THE COLD FRONT BY ABOUT 6
HOURS. HAVE BUMPED POPS UP A BIT OVER PORTIONS OF THE AREA FOR
TUESDAY DUE TO THE SLOWER PROGRESSION OF THE SYSTEM...BUT THE BASIC
IDEA IS THE SAME...LIKELY POPS JUST ABOUT EVERYWHERE EXCEPT CENTRAL
MISSOURI WHERE HIGH CHANCE IS THE RULE.
TUESDAY`S SHORTWAVE TAKES ON A NEGATIVE TILT AND LIFTS RAPIDLY
NORTHEAST INTO THE GREAT LAKES REGION ON WEDNESDAY...JUST IN TIME
FOR ANOTHER SHORTWAVE TO DROP INTO THE MIDWEST AND DIG ALL THE WAY
INTO THE LOWER MISSISSIPPI VALLEY. THIS WAVE WILL BRING A
REINFORCING SHOT OF COLD AIR INTO THE REGION...AND WE MIGHT ACTUALLY
GET OUR FIRST FREEZE OF THE SEASON IN ST. LOUIS FRIDAY MORNING.
THERE`S SOME CONCERN FOR LIGHT RAIN OR EVEN LIGHT SNOW ON
THANKSGIVING DAY...BUT IF THE GFS IS CORRECT THERE WON`T BE ENOUGH
MOISTURE TO SUPPORT PRECIPITATION...SO HAVE LEFT THANKSGIVING DAY
DRY FOR NOW.
CARNEY
&&
.AVIATION...
/1054 AM CST SUN NOV 22 2009/
FOR THE 18Z TAFS...ERN EDGE OF MID LVL CLOUDS OVER THE NWRN HALF
OF MO CONTINUE TO ERODE LATE THIS MRNG. COU WILL LIKELY LOSE THERE
10000 FT CEILING EARLY THIS AFTN. OTHERWISE JUST SOME CIRRUS CLOUDS
STREAMING NWD INTO STL/SUS N OF MID LVL LOW OVER NRN AL. MID-HI
LEVEL CLOUDS WILL LIKELY ADVECT BACK INTO THE TAF SITES TGT AS
A SHRTWV TROF OVER THE PLAINS MOVES EWD THRU NRN MO. MORE
SIGNIFICANT WILL BE THE LOW LEVEL CLOUD COVER...MOISTURE OVER THE
SERN US WHICH THE MODELS ADVECT NWD INTO THE TAF SITES BY EARLY
MON MRNG. WILL PUT A BKN025 CEILING IN THE TAFS BEGINNING AT
12-14Z MON. THE CEILING SHOULD GRADUALLY RISE INTO THE VFR
CATAGORY DURING THE AFTN ON MON BASED ON THE MODEL MOS CIG HGT
GUIDANCE. THERE ALSO MAY BE SOME LIGHT FOG LATE TGT AND MON MRNG
...AROUND 4-6SM BR BESIDES THE LOW LEVEL CLOUDINESS. THE E-SELY
SFC WNDS WILL CONTINUE THIS AFTN. IT APPEARS THAT THE MOS WIND
GUIDANCE IS A TAD TOO LGT AT 17Z SUN...WITH UIN AND COU OBS
REPORTING 12-13 KT SUSTAINED WNDS. THE SFC WNDS WILL WEAKEN THIS
EVNG THEN PICK UP AGAIN FROM A SELY DIRECTION BY LATE MON MRNG.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KEAX 221737
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1135 AM CST SUN NOV 22 2009
...UPDATED FOR AVIATION...
.DISCUSSION...
COUPLE OF UPPER LEVEL SYSTEMS WILL AFFECT THE CWA THROUGH THE MIDDLE
OF NEXT WEEK. THE LEAD SHORTWAVE AS SEEN IN THE LATEST WATER VAPOR
LOOP HAS REACHED THE CENTRAL AND SOUTHERN HIGH PLAINS. THIS FEATURE
WILL HAVE A MINIMAL IMPACT ON THE SENSIBLE WEATHER AS IT WILL BE
LACKING A SOURCE OF DEEP MOISTURE AND WILL BE WEAKENING AS IT TRACKS
EASTWARD TODAY. INCREASING ISENTROPIC LIFT ON THE 300/305K SURFACES
IS TAPPING INTO MID LEVEL MOISTURE LEFT OVER FROM AN UPPER SYSTEM
NOW TRACKING THROUGH MS/AL. MOST OF THE CWA WILL BE COVERED BY THESE
MID CLOUDS FOR MOST OF TODAY. THE FAR SOUTHEASTERN COUNTIES MAY SEE
SOME AFTERNOON SUN. EXPECT TO SEE A CONTINUATION OF ABOVE NORMAL
TEMPERATURES EVEN WITH THE EXTENSIVE MID CLOUD DECK MAV/NAM MOS
GUIDANCE LOOK PRETTY REASONABLE. RADAR SHOWS SOME RETURNS OVER
CENTRAL MO BUT THE SUB-CLOUD LAYER IS SO DRY THAT THE RAIN IS NOT
LIKELY REACHING THE GROUND. THIS MAY CHANGE TONIGHT AS INCREASING
PVA ASSOCIATED WITH THE HIGH PLAINS SHORTWAVE APPROACHES WHILE THE
RIGHT REAR QUADRANT OF A DEPARTING UPPER LEVEL JET SEGMENT PROVIDE
SOME ADDITIONAL LIFT. WILL ADD SLIGHT CHANCE POPS FOR THE NORTHEAST
CWA FOR TONIGHT. LATER SHIFTS MAY NEED TO RAISE POPS SHOULD THE VERY
DRY SUB-CLOUD LAYER BEGIN TO SATURATE.
A SECOND AND STRONGER UPPER SYSTEM IS STILL SLATED TO REACH THE
CENTRAL PLAINS ON MONDAY...AND PASS THROUGH THE CWA ON TUESDAY. THE
MODELS HAVE BEEN FAIRLY CONSISTENT ON TIMING...STRENGTH AND LOCATION
OF THE UPPER SYSTEM. AN ATTENDANT COLD FRONT WILL MOVE EAST THROUGH
THE CENTRAL PLAINS ON MONDAY AND PASS THROUGH THE CWA MONDAY NIGHT.
DUE TO GOOD CONTINUITY OF THE MODEL RUNS HAVE MORE CONFIDENCE TO
RAISE POPS INTO THE LIKELY CATEGORY FOR MONDAY NIGHT. INCREASING
UPPER LEVEL DYNAMICS SUPPLIED BY A NEGATIVELY TILTED UPPER TROUGH
AND PRONOUNCED UPPER JET SEGMENT IN EXCESS OF 90KTS WILL INTERACT
WITH STEEPENING MID LEVEL LAPSE RATES AND MUCAPES OF 100-200 J/KG TO
ALLOW CONVECTIVE SHOWERS AND POSSIBLY EVEN A FEW THUNDERSTORMS TO
FORM.
AS THE UPPER SYSTEM CLOSES OFF SHOULD SEE WARP AROUND CLOUD COVER
AND PATCHY LIGHT RAIN ROLL BACK INTO THE CWA ON TUESDAY WITH THE
NORTHERN SECTIONS MOST LIKELY TO SEE AN PRECIPITATION. PROGGED
SOUNDINGS SUGGEST THE PRECIPITATION SHOULD STAY LIQUID ALTHOUGH SOME
SNOW COULD MIX IN WITH THE RAIN OVER FAR NW MO. NOT MUCH OF A
DIURNAL RANGE EXPECTED AS STRONG COLD AIR ADVECTION WORKS IN UNDER
THE UPPER LOW.
GFS/ECMWF DEPICT A THIRD CLIPPER TYPE SYSTEM WILL BE CLOSE ON THE
HEELS OF THE CLOSED LOW BUT CONFIDENCE LOW ON HOW THIS FEATURE WILL
PLAY OUT AS CLIPPER SYSTEMS ARE DIFFICULT TO GET A HANDLE ON THIS
FAR OUT.
MJ
&&
.AVIATION...
FOR THE 18Z TAFS...VFR CONDITIONS ARE EXPECTED TO REMAIN IN PLACE
THROUGH THE DAYTIME HOURS AS WELL AS INTO THE EVENING. S/W TROUGH
CONTINUES TO RACE EASTWARD ACROSS WESTERN AND CENTRAL KS THIS
AFTN...WITH BROAD ISENTROPIC LIFT GENERATING LIGHT SHRA/SPRINKLES
NORTH OF THE TERMINALS. IN ADDITION...MODEST LOW-LVL THETA-E
ADVECTION HAS RESULTED IN A BAND OF MVFR/IFR STRATUS ACROSS CENTRAL
KS ALONG A STATIONARY FRONT AND SFC LOW.
THIS S/W WILL LIFT NE THROUGH THE TERMINALS OVERNIGHT
TONIGHT...HOWEVER ISENTROPIC LIFT DOES NOT LOOK STRONG ENOUGH TO
PRODUCE ANYTHING MORE THAN SPRINKLES...WITH HIGHER POPS NORTH OF
KSTJ. HOWEVER...LATER SHIFTS WILL NEED TO KEEP AN EYE ON MVFR/IFR
CIGS TO OUR WEST WITH ARE PROGGED TO LIFT NORTHWARD ALONG A
DEVELOPING SFC WARM FRONT BY 3 AM. THIS FRONT SHOULD SLOWLY LIFT
NORTHWARD AFTER DAYBREAK AND MAY PRODUCE A 4 TO 6 HOUR SPAN OF MVFR
TO PERHAPS EVEN IFR CIGS...WITH INCREASING BOUNDARY LAYER MOISTURE
TRAPPED ALONG THIS FRONT REDUCING VIS INTO MVFR CATEGORIES. WILL
INCLUDE A TEMPO GROUP FOR THIS OCCURRENCE ATTM...WITH PREVAILING
CONDITIONS AT KSTJ WHERE LOW-LVL ISENTROPIC LIFT WILL BE THE
GREATEST. AS UPR S/W LIFTS NE BY MID-MORNING A RETURN TO VFR
CONDITIONS WOULD BE LIKELY.
DUX
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KSGF 221736
AFDSGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1136 AM CST SUN NOV 22 2009
...UPDATE TO AVIATION...
.DISCUSSION...
FORECAST CHALLENGES CONTINUE TO BE TEMPERATURES THROUGH THE
FORECAST PERIOD...ALONG WITH PRECIP CHANCES MONDAY NIGHT INTO TUESDAY.
CURRENTLY...SURFACE RIDGING CONTINUES OVER THE AREA FROM A SURFACE
HIGH OVER THE GREAT LAKES AREA THIS MORNING. LOW PRESSURE OVER
LOUISIANA THIS MORNING CONTINUES TO GIVE US SOME MID LEVEL
CLOUDINESS STREAMING IN AROUND THE NORTH SIDE OF THE LOW. THIS HAS
KEPT TEMPERATURES FAIRLY WARM SO FAR THIS MORNING WITH LOW TO MID
50S FOR MOST AREAS EXCEPT OUR WESTERN COUNTIES...WHERE
TEMPERATURES HAVE DROPPED INTO THE THE UPPER 40S. WATER VAPOR
IMAGERY SHOWING TWO SHORTWAVES MOVING TOWARDS THE AREA FROM THE
WEST. FIRST...CURRENTLY LOCATED FROM WESTERN SOUTH DAKOTA TO
EASTERN NEW MEXICO WITH SECOND SYSTEM JUST COMING ONSHORE AND
MOVING INTO THE ROCKIES.
SKIES SHOULD BEGIN TO SCATTER OUT HERE TODAY AS THE GULF COAST LOW
MOVES EAST. EXPECTING VERY NICE TEMPERATURES FOR THIS TIME OF YEAR
WITH MID 60S AREA WIDE. FIRST SHORTWAVE EXPECTED TO MOVE THROUGH
THE CWA THIS EVENING. GIVEN THE DRY AIR THAT WILL BE IN PLACE
TODAY AND GULF MOISTURE RETURN CUT OFF FROM THE LOW TO OUR
SOUTH...BELIEVE THIS WILL BE MAINLY A DRY FROPA WITH SOME VARIABLE
CLOUDINESS. 850MB TEMPERATURES DO COOL ABOUT 4C...DOWN TO AROUND
+5C BY MONDAY MORNING...SO WOULD EXPECT TEMPERATURES TO BE
SLIGHTLY COOLER FOR MONDAY WITH LOWS IN THE LOW TO MID 40S AND
HIGHS IN THE LOW 60S.
THE SECOND SYSTEM BEGINS TO APPROACH THE AREA MONDAY EVENING INTO
TUESDAY. GOOD AGREEMENT BETWEEN THE MODELS WITH THIS SYSTEM
TRACKING THE COLD FRONT THROUGH MONDAY NIGHT INTO TUESDAY MORNING
AND HAVE GONE AHEAD AND INCREASED POPS INTO THE LIKELY CATEGORY
WITH THIS SYSTEM. THIS SYSTEM HAS A MUCH BETTER CHANCE OF GETTING
GULF MOISTURE RETURN. GFS SHOWING LOW 50 DEW POINTS OUT AHEAD OF
THE SURFACE FRONT MONDAY EVENING ACROSS EASTERN KANSAS AND WESTERN
MISSOURI. A 90KT JET MAX WILL MOVE THROUGH THE AREA WITH THIS LOW
AS WELL. INSTABILITY IS NOT ALL THAT GREAT WITH AROUND 100-150
J/KG OF INSTABILITY...SO HAVE INCLUDED MENTION OF THUNDERSTORMS IN
THE FORECAST FOR MONDAY EVENING AS THE FRONT MOVES INTO THE AREA.
PRETTY GOOD CAA BEHIND THIS SYSTEM FOR TUESDAY AS 850MB
TEMPERATURES FALL TO -2C ON THE GFS. UPPER LOW TRACKS ACROSS THE
AREA TUESDAY...WITH WRAP AROUND MOISTURE. WOULD EXPECT TUESDAY TO
BE CHARACTERIZED BY LOW CLOUDINESS AND LIGHT RAIN/DRIZZLE FOR MOST
OF THE DAY BEHIND THE COLD FRONT. WOULD EXPECT THE LOW CLOUDINESS
TO CONTINUE INTO WEDNESDAY BEFORE THE UPPER LOW PULLS OFF
WEDNESDAY AFTERNOON.
BOTH THE GFS AND ECMWF SHOW A SECOND CLOSED LOW CLIPPING THE AREA
WEDNESDAY NIGHT INTO THURSDAY WITH 850MB TEMPERATURES DROPPING TO
-8C...925MB TEMPERATURES DOWN TO AROUND -4C ACROSS CENTRAL
MISSOURI. MODELS NOT SHOWING ANY QPF WITH THIS SYSTEM...BUT WOULD
NOT BE SURPRISED TO SEE WHITE STUFF OUT OF THIS AS THEY DO NOT
TYPICALLY DO WELL ON PRECIP WITH THESE SYSTEMS THAT CLIP THE AREA
FROM THE NORTH. WILL HOLD OFF FOR ANOTHER MODEL RUN TO SEE IF
THESE COLDER TEMPERATURES PERSIST BEFORE ADDING ANY SNOW INTO THE
FORECAST. COLD TEMPERATURES CONTINUE INTO FRIDAY BEFORE SOUTHWEST
WINDS RETURN AS UPPER LEVEL RIDGE MOVES INTO THE AREA.
CLAYCOMB
&&
.AVIATION...
FOR THE 18Z KSGF...KJLN AND KBBG TAFS...VFR CONDITIONS WILL BE THE
RULE FOR THE REST OF THIS AFTERNOON AND THIS EVENING. AS SOUTHERLY
WINDS AND A SCATTERED TO BROKEN MID LEVEL CLOUD DECK PREVAILS OVER
THE TAF SITES. TONIGHT AN UPPER LEVEL DISTURBANCES WILL PUSH
THROUGH AREA. AS A RESULT AN AREA OF LOW LEVEL CLOUDS WILL DEVELOP
AND SPREAD INTO THE REGION...RESULTING IN MVFR CEILINGS. CANNOT
RULE OUT IFR CEILINGS TUESDAY MORNING...BUT AT THIS TIME
CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE IN THIS TAF PACKAGE.
WISE
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KLSX 221203
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
603 AM CST SUN NOV 22 2009
.DISCUSSION...
/438 AM CST SUN NOV 22 2009/
LITTLE CHANGE TO THE GOING FORECAST FOR THIS CYCLE. THE PRIMARY
FOCUS CONTINUES TO BE THE STORM FOR TUESDAY WHICH WILL BRING SOME
RAIN AND COOLER TEMPERATURES TO THE REGION. HOWEVER...FIRST IN LINE
IS A WEAK SHORTWAVE THAT WILL BRING CLOUDS AND PERHAPS SOME
SPRINKLES TO PARTS OF CENTRAL AND NORTHEAST MISSOURI AND WEST
CENTRAL ILLINOIS TODAY. RH PROGS ARE PRETTY PESSIMISTIC FOR ANY
CLEARING TODAY OVER CENTRAL MISSOURI SO HAVE KEPT CLOUDY/MOSTLY
CLOUDY CONDITIONS IN THE FORECAST. IT`S DEBATABLE WHETHER OR NOT TO
INCLUDE ANY POPS OR MENTION OF PRECIP AT ALL TODAY. SOUNDINGS SHOW
A VERY DRY LAYER AROUND 900 MB WITH DEWPOINT DEPRESSIONS OF NEARLY
30 DEGREES. WILL KEEP AN EYE ON THE RADAR AND SURFACE OBSERVATIONS
THIS MORNING AND UPDATE AS NECESSARY...BUT IF THOSE SOUNDINGS ARE
CORRECT ANYTHING SHORT OF A HEAVY THUNDERSTORM WILL HAVE TROUBLE
PRECIPITATING THROUGH THAT DRY LAYER. HAVE INTRODUCED SOME SLIGHT
CHANCE POPS FOR TONIGHT THO AS THE MAIN SHORTWAVE RIPPLES BY. LOW
LEVELS STILL LOOK PRETTY DRY...BUT THERE COULD BE ENOUGH ISENTROPIC
LIFT COUPLED WITH SHORTWAVE ENERGY TO KICK OUT A FEW LIGHT RAIN
SHOWERS.
THE MAIN SHOW WILL BEGIN EARLY TUESDAY MORNING AS A STRONG WAVES
DROPS OFF THE ROCKIES AND CLOSES OFF OVER THE PLAINS. LATEST
GUIDANCE APPEARS TO BE A BIT SLOWER THAN PREVIOUS FORECASTS WITH
RESPECT TO THE SURFACE FEATURES ASSOCIATED WITH THIS SYSTEM. HAVE
ACCORDINGLY SLOWED THE PROGRESSION OF THE COLD FRONT BY ABOUT 6
HOURS. HAVE BUMPED POPS UP A BIT OVER PORTIONS OF THE AREA FOR
TUESDAY DUE TO THE SLOWER PROGRESSION OF THE SYSTEM...BUT THE BASIC
IDEA IS THE SAME...LIKELY POPS JUST ABOUT EVERYWHERE EXCEPT CENTRAL
MISSOURI WHERE HIGH CHANCE IS THE RULE.
TUESDAY`S SHORTWAVE TAKES ON A NEGATIVE TILT AND LIFTS RAPIDLY
NORTHEAST INTO THE GREAT LAKES REGION ON WEDNESDAY...JUST IN TIME
FOR ANOTHER SHORTWAVE TO DROP INTO THE MIDWEST AND DIG ALL THE WAY
INTO THE LOWER MISSISSIPPI VALLEY. THIS WAVE WILL BRING A
REINFORCING SHOT OF COLD AIR INTO THE REGION...AND WE MIGHT ACTUALLY
GET OUR FIRST FREEZE OF THE SEASON IN ST. LOUIS FRIDAY MORNING.
THERE`S SOME CONCERN FOR LIGHT RAIN OR EVEN LIGHT SNOW ON
THANKSGIVING DAY...BUT IF THE GFS IS CORRECT THERE WON`T BE ENOUGH
MOISTURE TO SUPPORT PRECIPITATION...SO HAVE LEFT THANKSGIVING DAY
DRY FOR NOW.
CARNEY
&&
.AVIATION...
/543 AM CST SUN NOV 22 2009/
FOR THE 12Z TAFS...RATHER THICK BLANKET OF MID CLOUDS HAS BEEN
DRAPED OVER MOST OF MISSOURI DURING THE PREDAWN HOURS...HOWEVER
EASTERN EDGE OF THIS CLOUD DECK HAS BEEN ERODING WWD. EDGE
CURRENTLY EXTENDS FROM NEAR PPQ TO SUS...AND EXTRAPOLATION OF THIS
EDGE PLACES IT OVER UIN IN THE 15-16Z TIME FRAME AND BY COU BY
EARLY AFTERNOON...IN VERY GOOD AGREEMENT WITH THE MID LVL RH PROGS
FROM BOTH THE GFS AND NAM. IN THE STL AND SUS AREAS WHERE SKIES
HAVE NOW CLEARED RESIDUAL LO LEVEL MOISTURE MAY LEAD TO SEVERAL
HOURS OF MVFR VSBYS EARLY THIS MORNING...BUT ANY FOG WILL QUICKLY
LIFT BY 15Z. MID LEVEL CLOUDINESS WILL ATTEMPT TO OVERSPREAD THE
AREA ONCE AGAIN TONIGHT...WITH WEDGE OF DRIER AIR AOB 850MB HOLDING
LOWER CIGS AT BAY THROUGH 12Z.
TRUETT
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KEAX 221110
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
510 AM CST SUN NOV 22 2009
...UPDATED AVIATION...
.DISCUSSION...
COUPLE OF UPPER LEVEL SYSTEMS WILL AFFECT THE CWA THROUGH THE MIDDLE
OF NEXT WEEK. THE LEAD SHORTWAVE AS SEEN IN THE LATEST WATER VAPOR
LOOP HAS REACHED THE CENTRAL AND SOUTHERN HIGH PLAINS. THIS FEATURE
WILL HAVE A MINIMAL IMPACT ON THE SENSIBLE WEATHER AS IT WILL BE
LACKING A SOURCE OF DEEP MOISTURE AND WILL BE WEAKENING AS IT TRACKS
EASTWARD TODAY. INCREASING ISENTROPIC LIFT ON THE 300/305K SURFACES
IS TAPPING INTO MID LEVEL MOISTURE LEFT OVER FROM AN UPPER SYSTEM
NOW TRACKING THROUGH MS/AL. MOST OF THE CWA WILL BE COVERED BY THESE
MID CLOUDS FOR MOST OF TODAY. THE FAR SOUTHEASTERN COUNTIES MAY SEE
SOME AFTERNOON SUN. EXPECT TO SEE A CONTINUATION OF ABOVE NORMAL
TEMPERATURES EVEN WITH THE EXTENSIVE MID CLOUD DECK MAV/NAM MOS
GUIDANCE LOOK PRETTY REASONABLE. RADAR SHOWS SOME RETURNS OVER
CENTRAL MO BUT THE SUB-CLOUD LAYER IS SO DRY THAT THE RAIN IS NOT
LIKELY REACHING THE GROUND. THIS MAY CHANGE TONIGHT AS INCREASING
PVA ASSOCIATED WITH THE HIGH PLAINS SHORTWAVE APPROACHES WHILE THE
RIGHT REAR QUADRANT OF A DEPARTING UPPER LEVEL JET SEGMENT PROVIDE
SOME ADDITIONAL LIFT. WILL ADD SLIGHT CHANCE POPS FOR THE NORTHEAST
CWA FOR TONIGHT. LATER SHIFTS MAY NEED TO RAISE POPS SHOULD THE VERY
DRY SUB-CLOUD LAYER BEGIN TO SATURATE.
A SECOND AND STRONGER UPPER SYSTEM IS STILL SLATED TO REACH THE
CENTRAL PLAINS ON MONDAY...AND PASS THROUGH THE CWA ON TUESDAY. THE
MODELS HAVE BEEN FAIRLY CONSISTENT ON TIMING...STRENGTH AND LOCATION
OF THE UPPER SYSTEM. AN ATTENDANT COLD FRONT WILL MOVE EAST THROUGH
THE CENTRAL PLAINS ON MONDAY AND PASS THROUGH THE CWA MONDAY NIGHT.
DUE TO GOOD CONTINUITY OF THE MODEL RUNS HAVE MORE CONFIDENCE TO
RAISE POPS INTO THE LIKELY CATEGORY FOR MONDAY NIGHT. INCREASING
UPPER LEVEL DYNAMICS SUPPLIED BY A NEGATIVELY TILTED UPPER TROUGH
AND PRONOUNCED UPPER JET SEGMENT IN EXCESS OF 90KTS WILL INTERACT
WITH STEEPENING MID LEVEL LAPSE RATES AND MUCAPES OF 100-200 J/KG TO
ALLOW CONVECTIVE SHOWERS AND POSSIBLY EVEN A FEW THUNDERSTORMS TO
FORM.
AS THE UPPER SYSTEM CLOSES OFF SHOULD SEE WARP AROUND CLOUD COVER
AND PATCHY LIGHT RAIN ROLL BACK INTO THE CWA ON TUESDAY WITH THE
NORTHERN SECTIONS MOST LIKELY TO SEE AN PRECIPITATION. PROGGED
SOUNDINGS SUGGEST THE PRECIPITATION SHOULD STAY LIQUID ALTHOUGH SOME
SNOW COULD MIX IN WITH THE RAIN OVER FAR NW MO. NOT MUCH OF A
DIURNAL RANGE EXPECTED AS STRONG COLD AIR ADVECTION WORKS IN UNDER
THE UPPER LOW.
GFS/ECMWF DEPICT A THIRD CLIPPER TYPE SYSTEM WILL BE CLOSE ON THE
HEELS OF THE CLOSED LOW BUT CONFIDENCE LOW ON HOW THIS FEATURE WILL
PLAY OUT AS CLIPPER SYSTEMS ARE DIFFICULT TO GET A HANDLE ON THIS
FAR OUT.
MJ
&&
.AVIATION...
VFR 8K-10K FT DECK HAS BACKFILLED INTO TERMINAL CORRIDOR PRIOR TO
12Z...AND SHOULD LARGELY REMAIN IN TACT THROUGH THE DAYLIGHT HOURS.
ANY SPRINKLES/LIGHT SHOWERS SHOULD REMAIN TO THE EAST OVER CNTRL AND
NERN MISSOURI...THOUGH PATCHES OF VIRGA ARE PLAUSIBLE DURING THE
LATE MORNING AND AFTERNOON HOURS. WITH MEDIUM CONFIDENCE...HAVE
STAYED ON THE OPTIMISTIC SIDE REGARDING FLIGHT CATEGORIES TOWARDS
THE END OF THE TAF PERIOD...THOUGH SOME MODEL GUIDANCE SUGGESTS
MVFR/IFR CIGS CURRENTLY OVER CNTRL KANSAS REACHING TERMINALS AFTER
MIDNIGHT. FUTURE TAF PACKAGES MAY EVENTUALLY NEED TO INTRODUCE LOWER
FLIGHT RESTRICTIONS BASED ON MODEL AND OBSERVATIONAL TRENDS.
21
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KSGF 221100
AFDSGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
500 AM CST SUN NOV 22 2009
...UPDATE TO AVIATION...
.DISCUSSION...
FORECAST CHALLENGES CONTINUE TO BE TEMPERATURES THROUGH THE
FORECAST PERIOD...ALONG WITH PRECIP CHANCES MONDAY NIGHT INTO TUESDAY.
CURRENTLY...SURFACE RIDGING CONTINUES OVER THE AREA FROM A SURFACE
HIGH OVER THE GREAT LAKES AREA THIS MORNING. LOW PRESSURE OVER
LOUISIANA THIS MORNING CONTINUES TO GIVE US SOME MID LEVEL
CLOUDINESS STREAMING IN AROUND THE NORTH SIDE OF THE LOW. THIS HAS
KEPT TEMPERATURES FAIRLY WARM SO FAR THIS MORNING WITH LOW TO MID
50S FOR MOST AREAS EXCEPT OUR WESTERN COUNTIES...WHERE
TEMPERATURES HAVE DROPPED INTO THE THE UPPER 40S. WATER VAPOR
IMAGERY SHOWING TWO SHORTWAVES MOVING TOWARDS THE AREA FROM THE
WEST. FIRST...CURRENTLY LOCATED FROM WESTERN SOUTH DAKOTA TO
EASTERN NEW MEXICO WITH SECOND SYSTEM JUST COMING ONSHORE AND
MOVING INTO THE ROCKIES.
SKIES SHOULD BEGIN TO SCATTER OUT HERE TODAY AS THE GULF COAST LOW
MOVES EAST. EXPECTING VERY NICE TEMPERATURES FOR THIS TIME OF YEAR
WITH MID 60S AREA WIDE. FIRST SHORTWAVE EXPECTED TO MOVE THROUGH
THE CWA THIS EVENING. GIVEN THE DRY AIR THAT WILL BE IN PLACE
TODAY AND GULF MOISTURE RETURN CUT OFF FROM THE LOW TO OUR
SOUTH...BELIEVE THIS WILL BE MAINLY A DRY FROPA WITH SOME VARIABLE
CLOUDINESS. 850MB TEMPERATURES DO COOL ABOUT 4C...DOWN TO AROUND
+5C BY MONDAY MORNING...SO WOULD EXPECT TEMPERATURES TO BE
SLIGHTLY COOLER FOR MONDAY WITH LOWS IN THE LOW TO MID 40S AND
HIGHS IN THE LOW 60S.
THE SECOND SYSTEM BEGINS TO APPROACH THE AREA MONDAY EVENING INTO
TUESDAY. GOOD AGREEMENT BETWEEN THE MODELS WITH THIS SYSTEM
TRACKING THE COLD FRONT THROUGH MONDAY NIGHT INTO TUESDAY MORNING
AND HAVE GONE AHEAD AND INCREASED POPS INTO THE LIKELY CATEGORY
WITH THIS SYSTEM. THIS SYSTEM HAS A MUCH BETTER CHANCE OF GETTING
GULF MOISTURE RETURN. GFS SHOWING LOW 50 DEW POINTS OUT AHEAD OF
THE SURFACE FRONT MONDAY EVENING ACROSS EASTERN KANSAS AND WESTERN
MISSOURI. A 90KT JET MAX WILL MOVE THROUGH THE AREA WITH THIS LOW
AS WELL. INSTABILITY IS NOT ALL THAT GREAT WITH AROUND 100-150
J/KG OF INSTABILITY...SO HAVE INCLUDED MENTION OF THUNDERSTORMS IN
THE FORECAST FOR MONDAY EVENING AS THE FRONT MOVES INTO THE AREA.
PRETTY GOOD CAA BEHIND THIS SYSTEM FOR TUESDAY AS 850MB
TEMPERATURES FALL TO -2C ON THE GFS. UPPER LOW TRACKS ACROSS THE
AREA TUESDAY...WITH WRAP AROUND MOISTURE. WOULD EXPECT TUESDAY TO
BE CHARACTERIZED BY LOW CLOUDINESS AND LIGHT RAIN/DRIZZLE FOR MOST
OF THE DAY BEHIND THE COLD FRONT. WOULD EXPECT THE LOW CLOUDINESS
TO CONTINUE INTO WEDNESDAY BEFORE THE UPPER LOW PULLS OFF
WEDNESDAY AFTERNOON.
BOTH THE GFS AND ECMWF SHOW A SECOND CLOSED LOW CLIPPING THE AREA
WEDNESDAY NIGHT INTO THURSDAY WITH 850MB TEMPERATURES DROPPING TO
-8C...925MB TEMPERATURES DOWN TO AROUND -4C ACROSS CENTRAL
MISSOURI. MODELS NOT SHOWING ANY QPF WITH THIS SYSTEM...BUT WOULD
NOT BE SURPRISED TO SEE WHITE STUFF OUT OF THIS AS THEY DO NOT
TYPICALLY DO WELL ON PRECIP WITH THESE SYSTEMS THAT CLIP THE AREA
FROM THE NORTH. WILL HOLD OFF FOR ANOTHER MODEL RUN TO SEE IF
THESE COLDER TEMPERATURES PERSIST BEFORE ADDING ANY SNOW INTO THE
FORECAST. COLD TEMPERATURES CONTINUE INTO FRIDAY BEFORE SOUTHWEST
WINDS RETURN AS UPPER LEVEL RIDGE MOVES INTO THE AREA.
CLAYCOMB
&&
.AVIATION...
FOR THE 12Z TAFS...MID/UPPER LEVEL CLOUD COVER WILL PERSIST
THROUGH THE FORECAST PERIOD AS UPPER DISTURBANCE MOVES SOUTH OF
THE AREA AND ANOTHER MOVES ACROSS THE FORECAST AREA TODAY. NOT
MUCH LOW LEVEL MOISTURE EXPECTED AND CEILINGS WILL REMAIN VFR.
LINDENBERG
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KEAX 221041
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
441 AM CST SUN NOV 22 2009
.DISCUSSION...
COUPLE OF UPPER LEVEL SYSTEMS WILL AFFECT THE CWA THROUGH THE MIDDLE
OF NEXT WEEK. THE LEAD SHORTWAVE AS SEEN IN THE LATEST WATER VAPOR
LOOP HAS REACHED THE CENTRAL AND SOUTHERN HIGH PLAINS. THIS FEATURE
WILL HAVE A MINIMAL IMPACT ON THE SENSIBLE WEATHER AS IT WILL BE
LACKING A SOURCE OF DEEP MOISTURE AND WILL BE WEAKENING AS IT TRACKS
EASTWARD TODAY. INCREASING ISENTROPIC LIFT ON THE 300/305K SURFACES
IS TAPPING INTO MID LEVEL MOISTURE LEFT OVER FROM AN UPPER SYSTEM
NOW TRACKING THROUGH MS/AL. MOST OF THE CWA WILL BE COVERED BY THESE
MID CLOUDS FOR MOST OF TODAY. THE FAR SOUTHEASTERN COUNTIES MAY SEE
SOME AFTERNOON SUN. EXPECT TO SEE A CONTINUATION OF ABOVE NORMAL
TEMPERATURES EVEN WITH THE EXTENSIVE MID CLOUD DECK MAV/NAM MOS
GUIDANCE LOOK PRETTY REASONABLE. RADAR SHOWS SOME RETURNS OVER
CENTRAL MO BUT THE SUB-CLOUD LAYER IS SO DRY THAT THE RAIN IS NOT
LIKELY REACHING THE GROUND. THIS MAY CHANGE TONIGHT AS INCREASING
PVA ASSOCIATED WITH THE HIGH PLAINS SHORTWAVE APPROACHES WHILE THE
RIGHT REAR QUADRANT OF A DEPARTING UPPER LEVEL JET SEGMENT PROVIDE
SOME ADDITIONAL LIFT. WILL ADD SLIGHT CHANCE POPS FOR THE NORTHEAST
CWA FOR TONIGHT. LATER SHIFTS MAY NEED TO RAISE POPS SHOULD THE VERY
DRY SUB-CLOUD LAYER BEGIN TO SATURATE.
A SECOND AND STRONGER UPPER SYSTEM IS STILL SLATED TO REACH THE
CENTRAL PLAINS ON MONDAY...AND PASS THROUGH THE CWA ON TUESDAY. THE
MODELS HAVE BEEN FAIRLY CONSISTENT ON TIMING...STRENGTH AND LOCATION
OF THE UPPER SYSTEM. AN ATTENDANT COLD FRONT WILL MOVE EAST THROUGH
THE CENTRAL PLAINS ON MONDAY AND PASS THROUGH THE CWA MONDAY NIGHT.
DUE TO GOOD CONTINUITY OF THE MODEL RUNS HAVE MORE CONFIDENCE TO
RAISE POPS INTO THE LIKELY CATEGORY FOR MONDAY NIGHT. INCREASING
UPPER LEVEL DYNAMICS SUPPLIED BY A NEGATIVELY TILTED UPPER TROUGH
AND PRONOUNCED UPPER JET SEGMENT IN EXCESS OF 90KTS WILL INTERACT
WITH STEEPENING MID LEVEL LAPSE RATES AND MUCAPES OF 100-200 J/KG TO
ALLOW CONVECTIVE SHOWERS AND POSSIBLY EVEN A FEW THUNDERSTORMS TO
FORM.
AS THE UPPER SYSTEM CLOSES OFF SHOULD SEE WARP AROUND CLOUD COVER
AND PATCHY LIGHT RAIN ROLL BACK INTO THE CWA ON TUESDAY WITH THE
NORTHERN SECTIONS MOST LIKELY TO SEE AN PRECIPITATION. PROGGED
SOUNDINGS SUGGEST THE PRECIPITATION SHOULD STAY LIQUID ALTHOUGH SOME
SNOW COULD MIX IN WITH THE RAIN OVER FAR NW MO. NOT MUCH OF A
DIURNAL RANGE EXPECTED AS STRONG COLD AIR ADVECTION WORKS IN UNDER
THE UPPER LOW.
GFS/ECMWF DEPICT A THIRD CLIPPER TYPE SYSTEM WILL BE CLOSE ON THE
HEELS OF THE CLOSED LOW BUT CONFIDENCE LOW ON HOW THIS FEATURE WILL
PLAY OUT AS CLIPPER SYSTEMS ARE DIFFICULT TO GET A HANDLE ON THIS
FAR OUT.
MJ
&&
.AVIATION...
INCREASING SFC PRESSURE GRADIENT WILL KEEP BOUNDARY LAYER WINDS
MIXED OVERNIGHT...WHILE DRIER AIRMASS ADVECTS NORTHWEST OFF THE
OZARK PLATEAU...KEEPING WIDESPREAD VSBY RESTRICTIONS TO A MINIMUM
(SOME MVFR BR PERIODICALLY LIKELY AT KSTJ GIVEN ITS SHELTERED
LOCATION EARLY IN THE PERIOD). THINKING NARROW RIBBON OF MVFR/IFR
CIGS OBSERVED OVER WRN OKLA/CNTRL KANSAS WILL REMAIN TO THE WEST OF
THE TERMINALS...WITH ONLY HIGHER VFR CIGS AFFECTING WRN MISSOURI
INTO THE DAYLIGHT HOURS.
21
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KLSX 221038
AFDLSX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
438 AM CST SUN NOV 22 2009
.DISCUSSION...
/438 AM CST SUN NOV 22 2009/
LITTLE CHANGE TO THE GOING FORECAST FOR THIS CYCLE. THE PRIMARY
FOCUS CONTINUES TO BE THE STORM FOR TUESDAY WHICH WILL BRING SOME
RAIN AND COOLER TEMPERATURES TO THE REGION. HOWEVER...FIRST IN LINE
IS A WEAK SHORTWAVE THAT WILL BRING CLOUDS AND PERHAPS SOME
SPRINKLES TO PARTS OF CENTRAL AND NORTHEAST MISSOURI AND WEST
CENTRAL ILLINOIS TODAY. RH PROGS ARE PRETTY PESSIMISTIC FOR ANY
CLEARING TODAY OVER CENTRAL MISSOURI SO HAVE KEPT CLOUDY/MOSTLY
CLOUDY CONDITIONS IN THE FORECAST. IT`S DEBATABLE WHETHER OR NOT TO
INCLUDE ANY POPS OR MENTION OF PRECIP AT ALL TODAY. SOUNDINGS SHOW
A VERY DRY LAYER AROUND 900 MB WITH DEWPOINT DEPRESSIONS OF NEARLY
30 DEGREES. WILL KEEP AN EYE ON THE RADAR AND SURFACE OBSERVATIONS
THIS MORNING AND UPDATE AS NECESSARY...BUT IF THOSE SOUNDINGS ARE
CORRECT ANYTHING SHORT OF A HEAVY THUNDERSTORM WILL HAVE TROUBLE
PRECIPITATING THROUGH THAT DRY LAYER. HAVE INTRODUCED SOME SLIGHT
CHANCE POPS FOR TONIGHT THO AS THE MAIN SHORTWAVE RIPPLES BY. LOW
LEVELS STILL LOOK PRETTY DRY...BUT THERE COULD BE ENOUGH ISENTROPIC
LIFT COUPLED WITH SHORTWAVE ENERGY TO KICK OUT A FEW LIGHT RAIN
SHOWERS.
THE MAIN SHOW WILL BEGIN EARLY TUESDAY MORNING AS A STRONG WAVES
DROPS OFF THE ROCKIES AND CLOSES OFF OVER THE PLAINS. LATEST
GUIDANCE APPEARS TO BE A BIT SLOWER THAN PREVIOUS FORECASTS WITH
RESPECT TO THE SURFACE FEATURES ASSOCIATED WITH THIS SYSTEM. HAVE
ACCORDINGLY SLOWED THE PROGRESSION OF THE COLD FRONT BY ABOUT 6
HOURS. HAVE BUMPED POPS UP A BIT OVER PORTIONS OF THE AREA FOR
TUESDAY DUE TO THE SLOWER PROGRESSION OF THE SYSTEM...BUT THE BASIC
IDEA IS THE SAME...LIKELY POPS JUST ABOUT EVERYWHERE EXCEPT CENTRAL
MISSOURI WHERE HIGH CHANCE IS THE RULE.
TUESDAY`S SHORTWAVE TAKES ON A NEGATIVE TILT AND LIFTS RAPIDLY
NORTHEAST INTO THE GREAT LAKES REGION ON WEDNESDAY...JUST IN TIME
FOR ANOTHER SHORTWAVE TO DROP INTO THE MIDWEST AND DIG ALL THE WAY
INTO THE LOWER MISSISSIPPI VALLEY. THIS WAVE WILL BRING A
REINFORCING SHOT OF COLD AIR INTO THE REGION...AND WE MIGHT ACTUALLY
GET OUR FIRST FREEZE OF THE SEASON IN ST. LOUIS FRIDAY MORNING.
THERE`S SOME CONCERN FOR LIGHT RAIN OR EVEN LIGHT SNOW ON
THANKSGIVING DAY...BUT IF THE GFS IS CORRECT THERE WON`T BE ENOUGH
MOISTURE TO SUPPORT PRECIPITATION...SO HAVE LEFT THANKSGIVING DAY
DRY FOR NOW.
CARNEY
&&
.AVIATION...
/1115 PM CST SAT NOV 21 2009/
FOR THE 06Z TAFS...CLOUDS CONTINUE TO REDEVELOP OVER TAF SITES.
MODELS SHOW A CONTINUING FLOW OF MOISTURE INTO THE AREA. THEREFORE
BELIEVE THESE CLOUDS WILL PERSIST THRU MOST IF NOT ALL OF THE
OVERNIGHT HOURS. HAVE PULLED MENTION OF FG AT ALL SITES EXCEPT FOR
SUS. HAVE KEPT MENTION OF FG AT SUS TO ACCOUNT FOR POSS STEAM FG.
WINDS WILL REMAIN SELY TO ESELY DURING THE DAY ON SUNDAY AND BACK
TO BECOME ELY AROUND 00Z MONDAY.
TILLY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KSGF 220805
AFDSGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
205 AM CST SUN NOV 22 2009
.DISCUSSION...
FORECAST CHALLENGES CONTINUE TO BE TEMPERATURES THROUGH THE
FORECAST PERIOD...ALONG WITH PRECIP CHANCES MONDAY NIGHT INTO TUESDAY.
CURRENTLY...SURFACE RIDGING CONTINUES OVER THE AREA FROM A SURFACE
HIGH OVER THE GREAT LAKES AREA THIS MORNING. LOW PRESSURE OVER
LOUISIANA THIS MORNING CONTINUES TO GIVE US SOME MID LEVEL
CLOUDINESS STREAMING IN AROUND THE NORTH SIDE OF THE LOW. THIS HAS
KEPT TEMPERATURES FAIRLY WARM SO FAR THIS MORNING WITH LOW TO MID
50S FOR MOST AREAS EXCEPT OUR WESTERN COUNTIES...WHERE
TEMPERATURES HAVE DROPPED INTO THE THE UPPER 40S. WATER VAPOR
IMAGERY SHOWING TWO SHORTWAVES MOVING TOWARDS THE AREA FROM THE
WEST. FIRST...CURRENTLY LOCATED FROM WESTERN SOUTH DAKOTA TO
EASTERN NEW MEXICO WITH SECOND SYSTEM JUST COMING ONSHORE AND
MOVING INTO THE ROCKIES.
SKIES SHOULD BEGIN TO SCATTER OUT HERE TODAY AS THE GULF COAST LOW
MOVES EAST. EXPECTING VERY NICE TEMPERATURES FOR THIS TIME OF YEAR
WITH MID 60S AREA WIDE. FIRST SHORTWAVE EXPECTED TO MOVE THROUGH
THE CWA THIS EVENING. GIVEN THE DRY AIR THAT WILL BE IN PLACE
TODAY AND GULF MOISTURE RETURN CUT OFF FROM THE LOW TO OUR
SOUTH...BELIEVE THIS WILL BE MAINLY A DRY FROPA WITH SOME VARIABLE
CLOUDINESS. 850MB TEMPERATURES DO COOL ABOUT 4C...DOWN TO AROUND
+5C BY MONDAY MORNING...SO WOULD EXPECT TEMPERATURES TO BE
SLIGHTLY COOLER FOR MONDAY WITH LOWS IN THE LOW TO MID 40S AND
HIGHS IN THE LOW 60S.
THE SECOND SYSTEM BEGINS TO APPROACH THE AREA MONDAY EVENING INTO
TUESDAY. GOOD AGREEMENT BETWEEN THE MODELS WITH THIS SYSTEM
TRACKING THE COLD FRONT THROUGH MONDAY NIGHT INTO TUESDAY MORNING
AND HAVE GONE AHEAD AND INCREASED POPS INTO THE LIKELY CATEGORY
WITH THIS SYSTEM. THIS SYSTEM HAS A MUCH BETTER CHANCE OF GETTING
GULF MOISTURE RETURN. GFS SHOWING LOW 50 DEW POINTS OUT AHEAD OF
THE SURFACE FRONT MONDAY EVENING ACROSS EASTERN KANSAS AND WESTERN
MISSOURI. A 90KT JET MAX WILL MOVE THROUGH THE AREA WITH THIS LOW
AS WELL. INSTABILITY IS NOT ALL THAT GREAT WITH AROUND 100-150
J/KG OF INSTABILITY...SO HAVE INCLUDED MENTION OF THUNDERSTORMS IN
THE FORECAST FOR MONDAY EVENING AS THE FRONT MOVES INTO THE AREA.
PRETTY GOOD CAA BEHIND THIS SYSTEM FOR TUESDAY AS 850MB
TEMPERATURES FALL TO -2C ON THE GFS. UPPER LOW TRACKS ACROSS THE
AREA TUESDAY...WITH WRAP AROUND MOISTURE. WOULD EXPECT TUESDAY TO
BE CHARACTERIZED BY LOW CLOUDINESS AND LIGHT RAIN/DRIZZLE FOR MOST
OF THE DAY BEHIND THE COLD FRONT. WOULD EXPECT THE LOW CLOUDINESS
TO CONTINUE INTO WEDNESDAY BEFORE THE UPPER LOW PULLS OFF
WEDNESDAY AFTERNOON.
BOTH THE GFS AND ECMWF SHOW A SECOND CLOSED LOW CLIPPING THE AREA
WEDNESDAY NIGHT INTO THURSDAY WITH 850MB TEMPERATURES DROPPING TO
-8C...925MB TEMPERATURES DOWN TO AROUND -4C ACROSS CENTRAL
MISSOURI. MODELS NOT SHOWING ANY QPF WITH THIS SYSTEM...BUT WOULD
NOT BE SURPRISED TO SEE WHITE STUFF OUT OF THIS AS THEY DO NOT
TYPICALLY DO WELL ON PRECIP WITH THESE SYSTEMS THAT CLIP THE AREA
FROM THE NORTH. WILL HOLD OFF FOR ANOTHER MODEL RUN TO SEE IF
THESE COLDER TEMPERATURES PERSIST BEFORE ADDING ANY SNOW INTO THE
FORECAST. COLD TEMPERATURES CONTINUE INTO FRIDAY BEFORE SOUTHWEST
WINDS RETURN AS UPPER LEVEL RIDGE MOVES INTO THE AREA.
CLAYCOMB
&&
.AVIATION...
FOR THE 22/0600Z KSGF/KJLN/KBBG TAFS...VFR CEILINGS ARE EXPECTED
AT TIMES AS A DISTURBANCE MOVES WELL SOUTH AND EAST OF THE AREA.
AN UPPER LEVEL DISTURBANCE WILL MOVE W-E THROUGH MO LATE
SUNDAY...BUT WITH LIMITED MOISTURE...VFR CONDITIONS ARE EXPECTED TO
CONTINUE.
DSA
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KSGF 220522
AFDSGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1122 PM CST SAT NOV 21 2009
...UPDATE TO AVIATION...
.DISCUSSION...
THE MAIN FORECAST FOCUS WAS ON EARLY NEXT WEEK AS THIS WILL BE OUR
NEXT SHOT AT PRECIPITATION. THIS WILL BE THE START OF A LARGE
SCALE PATTERN CHANGE AS THE UPPER LEVEL FLOW BECOMES MORE
AMPLIFIED AND NORTHWESTERLY ACROSS THE CENTRAL UNITED STATES. THIS
WILL RESULT IN BELOW NORMAL TEMPERATURES FOR THE MID TO LATE WEEK
PERIOD.
A RATHER FLAT AND PROGRESSIVE UPPER LEVEL PATTERN WILL PERSIST FOR
THE REMAINDER OF THIS WEEKEND. WE WILL SEE ONE WEAK SHORT WAVE
TROUGH CROSS THE REGION SUNDAY NIGHT...BUT MOISTURE WILL BE VERY
LIMITED. COULD SEE A SHOWER ACROSS SOUTHEAST MISSOURI...BUT THAT
WOULD BE ABOUT IT. STUCK VERY CLOSE TO MAV/MET BLEND FOR
TEMPERATURES FOR THE REMAINDER OF THE WEEKEND.
THE PATTERN WILL SLOWLY BECOME MORE AMPLIFIED NEXT WEEK. DIGGING
POTENTIAL WILL INCREASE THROUGHOUT THE WEEK FOR ANY SHORT WAVE
ENERGY ORIGINATING FROM THE PACIFIC NORTHWEST OR WESTERN CANADA.
THE FIRST SUCH WAVE WILL MOVE INTO THE NORTHERN AND CENTRAL
PLAINS FROM LATE MONDAY INTO TUESDAY. WE WILL SEE SOME INCREASE IN
LOW LEVEL MOISTURE AHEAD OF THIS FEATURE AS LOW LEVEL WINDS
INCREASE OUT OF THE SOUTHEAST AND SOUTH. A COLD FRONT ASSOCIATED
WITH THIS UPPER LEVEL ENERGY WILL LIKELY BE THE FOCUS FOR
PRECIPITATION CHANCES. CURRENT THINKING IS THIS FRONT WILL PASS
THROUGH THE OZARKS MONDAY NIGHT. HAVE RAISED POPS FOR THIS PERIOD
INTO THE HIGH CHANCE CATEGORY. MAY SEE SOME LINGERING SHOWERS INTO
TUESDAY ACROSS CENTRAL MISSOURI.
GLOBAL MODELS CONTINUE TO ADVERTISE A SECOND WAVE STRONGLY DIGGING
IN BEHIND THIS INITIAL WAVE AROUND MIDWEEK. THIS WAVE WILL LIKELY
BRING A STRONGER COLD FRONT ACROSS THE AREA...WITH 850 MB
TEMPERATURES PROGGED TO DIP INTO THE -5 TO -10 DEGREE CELSIUS
RANGE BY BOTH THE 12Z GFS AND ECMWF. THEREFORE CUT TEMPERATURES
STARTING AROUND MIDWEEK. IT IS QUITE POSSIBLE THAT WE SEE OUR
FIRST WIDESPREAD HARD FREEZE ACROSS THE REGION LATER NEXT WEEK. AM
NOT SEEING MUCH IF ANY PRECIPITATION THREAT LATER NEXT WEEK WITH
THE POSSIBLE EXCEPTION OF CENTRAL MISSOURI CLOSER TO THE TRACK OF
THAT SECOND WAVE.
SCHAUMANN
&&
.AVIATION...
FOR THE 22/0600Z KSGF/KJLN/KBBG TAFS...VFR CEILINGS ARE EXPECTED
AT TIMES AS A DISTURBANCE MOVES WELL SOUTH AND EAST OF THE AREA.
AN UPPER LEVEL DISTURBANCE WILL MOVE W-E THROUGH MO LATE
SUNDAY...BUT WITH LIMITED MOISTURE...VFR CONDITIONS ARE EXPECTED TO
CONTINUE. DSA
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KLSX 220521
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1121 PM CST SAT NOV 21 2009
.DISCUSSION...
/330 PM CST SAT NOV 21 2009/
RATHER BENIGN WEATHER IS EXPECTED ACROSS THE REGION THRU MONDAY
WITH WEAK SFC RIDGING DOMINATING AND NUETRAL TO WEAK WAA FORECAST.
THE UPPER LOW CURRENTLY INVOF EXTREME ERN TX IS FORECAST TO REMAIN
WELL SOUTH OF THE AREA AS IT MOVES EWD INTO THE LOWER TN VALLEY ON
SUNDAY IN RESPONSE TO THE UPSTREAM KICKER SHORTWV MOVING THRU THE
GREAT BASIN ATTM. WITH LITTLE REAL OVERALL CHANGE IN THE AIR
MASS...TEMPERATURES WILL TO A DEGREE BE DEPENDENT ON THE AMOUNT OF
CLOUDS. MAKING THIS A LITTLE MORE CHALLENGING IS THE FACT THE
MODEL RH FIELDS HAVE BEEN RATHER POOR OVER THE LAST FEW DAYS IN
DEPICTING THE CLOUDS. I THINK FOR THE MOST PART THE CLOUDS TONIGHT
WILL DECREASE AND MOVE NNEWD AND THE GREATEST CLOUD COVER ON
SUNDAY WILL RESIDE IN THE WRN PORTION OF MO TOUCHING PORTIONS OF
CENTRAL AND NE MO AS WELL. THE FORECAST TEMPERATURE ARE A BLEND OF
PERSISTENCE AND THE WARMER SIDE OF THE MOS GUIDANCE SUITE.
THE MAIN EMPHASIS THIS FORECAST PERIOD WILL BE ON THE MID/UPPER
LOW FORECAST TO DEVELOP IN THE NORTHERN ROCKIES ON SUNDAY NIGHT
AND MOVE INTO THE MIDDLE MS VALLEY ON TUESDAY. THERE IS SOME
SPREAD ON THE LOW POSITION BY 00Z WED...BUT IT IS NOT EXCEEDINGLY
GREAT. A CONSENSUS POSITION WOULD BE INVOF SE IA...WITH THE LOW
EXITING INTO THE LOWER GREAT LAKES BY WEDNESDAY MORNING IN
RESPONSE TO THE NEXT DIGGING UPSTREAM SHORTWV TROF/UPPER LOW. IN
TERMS OF SENSIBLE WEATHER...WILL NEED TO KEEP AN EYE ON A LEAD
IMPULSE MOVING THRU THE AREA ON SUNDAY NIGHT/EARLY MON...WHICH HAS A
VERY LOW CHANCE OF BRINGING A SPRINKLE OR LGT SHOWER TO FAR NRN
SECTIONS. OTHERWISE PCPN CHANCES WILL RAMP UP MONDAY NIGHT INTO
TUESDAY WITH THE STG MID/UPPER LOW-TROF. LOW LEVEL MOISTURE WILL
BE RATHER DISMAL AHEAD OF THIS FEATURE AND THE ATTENDANT
CDFNT...HOWEVER LARGE SCALE ASCENT WILL BE QUITE ROBUST ALONG WITH
PLENTIFUL MID LEVEL MOISTURE...SUPPORTIVE OF A BAND OF RAIN WITH
CLOUD BASES IN THE MID LEVELS. ACCORDINGLY I HAVE BOOSTED POPS IN
THE WESTERN CWA ON MONDAY NIGHT...AND IN THE ERN CWA ON TUESDAY.
SOME GOOD CAA WILL OCCUR IN THE WAKE OF THE FRONT ALONG WITH
PROBABLY A DECENT AMOUNT OF STRATUS.
A CHILLY PERIOD WITH BELOW AVERAGE TEMPERATURES IS EXPECTED
WEDNESDAY INTO THURSDAY WITH THE AFOREMENTIONED SECONDARY SHRTWV
TROF/UPPER LOW DIGGING INTO THE REGION AND BRING A COLDER
REINFORCING SHOT OF COLD AIR. THERE HAD BEEN SOME DIFFERENCES IN
THE EXTENDED RANGE MODELS WITH RESPECT TO THIS SCENARIO...BUT WITH
THE NEW 12Z ECMWF RUN...THEY HAVE ALL COME ONBOARD. EXPECTING
MODERATION OF THE TEMPERATURES TO ABOVE NORMAL NEXT WEEKEND AS THE
TROF BEGINS EXITING THE EASTERN SEABOARD AND HEIGHTS RISE ALOFT.
GLASS
&&
.AVIATION...
/1115 PM CST SAT NOV 21 2009/
FOR THE 06Z TAFS...CLOUDS CONTINUE TO REDEVELOP OVER TAF SITES.
MODELS SHOW A CONTINUING FLOW OF MOISTURE INTO THE AREA. THEREFORE
BELIEVE THESE CLOUDS WILL PERSIST THRU MOST IF NOT ALL OF THE
OVERNIGHT HOURS. HAVE PULLED MENTION OF FG AT ALL SITES EXCEPT FOR
SUS. HAVE KEPT MENTION OF FG AT SUS TO ACCOUNT FOR POSS STEAM FG.
WINDS WILL REMAIN SELY TO ESELY DURING THE DAY ON SUNDAY AND BACK
TO BECOME ELY AROUND 00Z MONDAY.
TILLY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KEAX 220510
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1110 PM CST SAT NOV 21 2009
...UPDATED AVIATION...
.UPDATE...
WILL PUT IN A PERIOD OF FOG AROUND THE KANSAS CITY METRO AREA FOR
LATE THIS EVENING BEFORE DRIER AIR OVER THE OZARKS IS PULLED INTO
THE REGION. WILL ALSO SCALE BACK CLOUD COVER AS DRIER SPREADS
NORTHWARD.
PC
&&
.DISCUSSION...
/346 PM CST SAT NOV 21 2009/
A WEAK WARM FRONT WAS LOCATED ACROSS THE SRN CWA WITH LOW LEVEL
MOISTURE LOCALLY POOLED NEAR THE BOUNDARY. THE BOUNDARY WILL SHIFT
QUICKLY NORTH AND DISSIPATE. AS PER FCST SOUNDINGS SUGGEST...THE
MOISTURE IS QUITE SHALLOW. THIS APPEARS REASONABLE GIVEN THE LOWER
DEWPOINTS WELL TO OUR SOUTH...IN AREAS WHERE DEEPER MIXING HAS
OCCURRED. GIVEN INTERVALS OF CLOUD COVER TONIGHT AND STRONGER SE
WINDS...DO NOT EXPECT WIDESPREAD DENSE FOG TONIGHT. GIVEN THE MIXY
NATURE OF THE SOUNDINGS JUST ABOVE THE SFC...STRATUS WOULD LIKELY BE
THE RESULT IF MOISTURE WAS DEEP ENOUGH. AT THE CURRENT TIME...MOIST
LAYER APPEARS INSUFFICIENT FOR STRATUS. THE ONLY EXCEPTION MAY BE
ACROSS THE NRN GRIDS TONIGHT WHERE LOW LEVEL MOISTURE IS A LITTLE
DEEPER.
WILL INTRODUCE PATCHY FOG FOR THE NRN GRIDS TONIGHT AND LET THE
EVENING SHIFT MAKE ANY REFINEMENTS BASED ON CURRENT TRENDS.
MOISTURE IMAGERY DEPICTS A SHORTWAVE MOVING INTO THE SRN AND CNTRL
ROCKIES. MODELS SUGGEST THAT THIS SHORTWAVE WILL EJECT ENE INTO THE
CWA SUN NIGHT. MOIST IS LIMITED WITH FORCING RATHER WEAK. CANNOT
RULE OUT A FEW SPRINKLES...BUT WILL NOT INTRODUCE AT THIS TIME.
OTHERWISE...MAIN CONCERN IS LATE MON AFTN AND MON NIGHT WHEN A STG
UPPER LEVEL LOW MOVES INTO THE PLAINS. THE MODELS HAVE A GENERAL
CONSENSUS IN MVG THE UPPER LEVEL LOW NR THE MO/IA BDR MON NGT AND
TUES WITH A STG WAVE MVG AROUND THE SRN PERIPHERY OF THE UPPER LEVEL
LOW. MUCH OF THE CWA IS IN THE FAVORABLE QUAD OF A 90KT H3 SPEED MAX
MON NGT WITH A MODEST PVU MAX ROTATING THROUGH MISSOURI. GIVEN THE
LOW STATIC STABILITY AND MODEST QG FORCING...HAVE INCREASED POPS FOR
LATE MON AFTN AND MON NGT. IN ADDITION...CANNOT RULE OUT AN ISOLATED
THUNDERSTORM GIVEN THE POTENTIAL FOR MUCAPES AROUND 100 J/KG.
DB
MEDIUM RANGE (TUESDAY THROUGH SATURDAY)...
OVERALL DECENT AGREEMENT AMONG ENSEMBLE GUIDANCE WITH RESPECT TO THE
UPPER AIR PATTERN THROUGH THE UPCOMING WORK WEEK. BY THE BEGINNING
OF THE WEEK...SHORT WAVE TROUGH IS EXPECTED DIVE ACROSS THE CENTRAL
CONUS BRINGING INCREASING PRECIPITATION CHANCES TO THE AREA.
DIFFERENCES IN THE EXACT LOCATION AND TIMING OF THIS FEATURE IS
EVIDENT AMONG VARIOUS SOLUTIONS...HOWEVER THE GENERAL IDEA IS
CERTAINLY CONSISTENT. BY TUESDAY...UPPER LOW WILL SLIDE ACROSS THE
CENTRAL PLAINS AND MIDWEST WITH LOCATION AND TIMING BY THIS TIME
FRAME KEY IN DETERMINING WHERE PRECIP IS MOST LIKELY AND WHEN ITS
EXPECTED TO PUSH EAST OF THE CWA. WILL KEEP HIGHEST RAIN CHANCES
ACROSS THE NORTHERN HALF OF THE CWA FOR TUESDAY...SLIDING ACTIVITY
EAST WITH TIME THROUGH TUESDAY NIGHT AND WEDNESDAY.
UPPER TROUGH AXIS APPEARS TO BE FAIRLY PROGRESSIVE WITH ADDITIONAL
SHORT WAVE ENERGY QUICK ON ITS HEELS. LINGERING PRECIP/CLOUD COVER
MAY BE EVIDENT THROUGH MIDWEEK AS SECONDARY SHORT WAVE TROUGH DIVES
SOUTH ON THE BACKSIDE OF DEPARTING SYSTEM. THIS WILL ALSO SERVE TO
BRING SOME SLIGHTLY COOLER AIR SOUTHWARD INTO THE MIDWESTERN STATES
BY WEDNESDAY AND THURSDAY. UPPER SHORT WAVE RIDGING WILL THEN
TRANSLATE ATOP THE REGION FOR THE LATTER PART OF THE WEEK AND INTO
THE WEEK BRINGING WARMER TEMPS.
DEROCHE
&&
.AVIATION...
INCREASING SFC PRESSURE GRADIENT WILL KEEP BOUNDARY LAYER WINDS
MIXED OVERNIGHT...WHILE DRIER AIRMASS ADVECTS NORTHWEST OFF THE
OZARK PLATEAU...KEEPING WIDESPREAD VSBY RESTRICTIONS TO A MINIMUM
(SOME MVFR BR PERIODICALLY LIKELY AT KSTJ GIVEN ITS SHELTERED
LOCATION EARLY IN THE PERIOD). THINKING NARROW RIBBON OF MVFR/IFR
CIGS OBSERVED OVER WRN OKLA/CNTRL KANSAS WILL REMAIN TO THE WEST OF
THE TERMINALS...WITH ONLY HIGHER VFR CIGS AFFECTING WRN MISSOURI
INTO THE DAYLIGHT HOURS.
21
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KEAX 220342
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
942 PM CST SAT NOV 21 2009
.UPDATE...
WILL PUT IN A PERIOD OF FOG AROUND THE KANSAS CITY METRO AREA FOR
LATE THIS EVENING BEFORE DRIER AIR OVER THE OZARKS IS PULLED INTO
THE REGION. WILL ALSO SCALE BACK CLOUD COVER AS DRIER SPREADS
NORTHWARD.
PC
&&
.DISCUSSION...
/346 PM CST SAT NOV 21 2009/
A WEAK WARM FRONT WAS LOCATED ACROSS THE SRN CWA WITH LOW LEVEL
MOISTURE LOCALLY POOLED NEAR THE BOUNDARY. THE BOUNDARY WILL SHIFT
QUICKLY NORTH AND DISSIPATE. AS PER FCST SOUNDINGS SUGGEST...THE
MOISTURE IS QUITE SHALLOW. THIS APPEARS REASONABLE GIVEN THE LOWER
DEWPOINTS WELL TO OUR SOUTH...IN AREAS WHERE DEEPER MIXING HAS
OCCURRED. GIVEN INTERVALS OF CLOUD COVER TONIGHT AND STRONGER SE
WINDS...DO NOT EXPECT WIDESPREAD DENSE FOG TONIGHT. GIVEN THE MIXY
NATURE OF THE SOUNDINGS JUST ABOVE THE SFC...STRATUS WOULD LIKELY BE
THE RESULT IF MOISTURE WAS DEEP ENOUGH. AT THE CURRENT TIME...MOIST
LAYER APPEARS INSUFFICIENT FOR STRATUS. THE ONLY EXCEPTION MAY BE
ACROSS THE NRN GRIDS TONIGHT WHERE LOW LEVEL MOISTURE IS A LITTLE
DEEPER.
WILL INTRODUCE PATCHY FOG FOR THE NRN GRIDS TONIGHT AND LET THE
EVENING SHIFT MAKE ANY REFINEMENTS BASED ON CURRENT TRENDS.
MOISTURE IMAGERY DEPICTS A SHORTWAVE MOVING INTO THE SRN AND CNTRL
ROCKIES. MODELS SUGGEST THAT THIS SHORTWAVE WILL EJECT ENE INTO THE
CWA SUN NIGHT. MOIST IS LIMITED WITH FORCING RATHER WEAK. CANNOT
RULE OUT A FEW SPRINKLES...BUT WILL NOT INTRODUCE AT THIS TIME.
OTHERWISE...MAIN CONCERN IS LATE MON AFTN AND MON NIGHT WHEN A STG
UPPER LEVEL LOW MOVES INTO THE PLAINS. THE MODELS HAVE A GENERAL
CONSENSUS IN MVG THE UPPER LEVEL LOW NR THE MO/IA BDR MON NGT AND
TUES WITH A STG WAVE MVG AROUND THE SRN PERIPHERY OF THE UPPER LEVEL
LOW. MUCH OF THE CWA IS IN THE FAVORABLE QUAD OF A 90KT H3 SPEED MAX
MON NGT WITH A MODEST PVU MAX ROTATING THROUGH MISSOURI. GIVEN THE
LOW STATIC STABILITY AND MODEST QG FORCING...HAVE INCREASED POPS FOR
LATE MON AFTN AND MON NGT. IN ADDITION...CANNOT RULE OUT AN ISOLATED
THUNDERSTORM GIVEN THE POTENTIAL FOR MUCAPES AROUND 100 J/KG.
DB
MEDIUM RANGE (TUESDAY THROUGH SATURDAY)...
OVERALL DECENT AGREEMENT AMONG ENSEMBLE GUIDANCE WITH RESPECT TO THE
UPPER AIR PATTERN THROUGH THE UPCOMING WORK WEEK. BY THE BEGINNING
OF THE WEEK...SHORT WAVE TROUGH IS EXPECTED DIVE ACROSS THE CENTRAL
CONUS BRINGING INCREASING PRECIPITATION CHANCES TO THE AREA.
DIFFERENCES IN THE EXACT LOCATION AND TIMING OF THIS FEATURE IS
EVIDENT AMONG VARIOUS SOLUTIONS...HOWEVER THE GENERAL IDEA IS
CERTAINLY CONSISTENT. BY TUESDAY...UPPER LOW WILL SLIDE ACROSS THE
CENTRAL PLAINS AND MIDWEST WITH LOCATION AND TIMING BY THIS TIME
FRAME KEY IN DETERMINING WHERE PRECIP IS MOST LIKELY AND WHEN ITS
EXPECTED TO PUSH EAST OF THE CWA. WILL KEEP HIGHEST RAIN CHANCES
ACROSS THE NORTHERN HALF OF THE CWA FOR TUESDAY...SLIDING ACTIVITY
EAST WITH TIME THROUGH TUESDAY NIGHT AND WEDNESDAY.
UPPER TROUGH AXIS APPEARS TO BE FAIRLY PROGRESSIVE WITH ADDITIONAL
SHORT WAVE ENERGY QUICK ON ITS HEELS. LINGERING PRECIP/CLOUD COVER
MAY BE EVIDENT THROUGH MIDWEEK AS SECONDARY SHORT WAVE TROUGH DIVES
SOUTH ON THE BACKSIDE OF DEPARTING SYSTEM. THIS WILL ALSO SERVE TO
BRING SOME SLIGHTLY COOLER AIR SOUTHWARD INTO THE MIDWESTERN STATES
BY WEDNESDAY AND THURSDAY. UPPER SHORT WAVE RIDGING WILL THEN
TRANSLATE ATOP THE REGION FOR THE LATTER PART OF THE WEEK AND INTO
THE WEEK BRINGING WARMER TEMPS.
DEROCHE
&&
.AVIATION...
/522 PM CST SAT NOV 21 2009/
FOR THE 00Z TAFS...WARM FRONT LIFTING NORTH ACROSS THE TAF SITES
THIS EVENING WILL BRING A PERIOD OF MVFR CIGS AND MAY ALSO HAVE SOME
MVFR FOG. ONCE THIS LIFTS NORTH BETWEEN 03 TO 04Z...PRESSURE
GRADIENT MAY BE ENOUGH TO PRECLUDE DENSE FOG OVERNIGHT...BUT WILL
KEEP THE MVFR VSBYS FROM THE PREVIOUS TAF GIVEN THE EXPECTED SMALL
TEMP DEWPOINT SPREAD. VFR CONDITIONS EXPECTED ON SUNDAY.
PC
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KSGF 212335
AFDSGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
535 PM CST SAT NOV 21 2009
...UPDATE TO AVIATION...
.DISCUSSION...
THE MAIN FORECAST FOCUS WAS ON EARLY NEXT WEEK AS THIS WILL BE OUR
NEXT SHOT AT PRECIPITATION. THIS WILL BE THE START OF A LARGE
SCALE PATTERN CHANGE AS THE UPPER LEVEL FLOW BECOMES MORE
AMPLIFIED AND NORTHWESTERLY ACROSS THE CENTRAL UNITED STATES. THIS
WILL RESULT IN BELOW NORMAL TEMPERATURES FOR THE MID TO LATE WEEK
PERIOD.
A RATHER FLAT AND PROGRESSIVE UPPER LEVEL PATTERN WILL PERSIST FOR
THE REMAINDER OF THIS WEEKEND. WE WILL SEE ONE WEAK SHORT WAVE
TROUGH CROSS THE REGION SUNDAY NIGHT...BUT MOISTURE WILL BE VERY
LIMITED. COULD SEE A SHOWER ACROSS SOUTHEAST MISSOURI...BUT THAT
WOULD BE ABOUT IT. STUCK VERY CLOSE TO MAV/MET BLEND FOR
TEMPERATURES FOR THE REMAINDER OF THE WEEKEND.
THE PATTERN WILL SLOWLY BECOME MORE AMPLIFIED NEXT WEEK. DIGGING
POTENTIAL WILL INCREASE THROUGHOUT THE WEEK FOR ANY SHORT WAVE
ENERGY ORIGINATING FROM THE PACIFIC NORTHWEST OR WESTERN CANADA.
THE FIRST SUCH WAVE WILL MOVE INTO THE NORTHERN AND CENTRAL
PLAINS FROM LATE MONDAY INTO TUESDAY. WE WILL SEE SOME INCREASE IN
LOW LEVEL MOISTURE AHEAD OF THIS FEATURE AS LOW LEVEL WINDS
INCREASE OUT OF THE SOUTHEAST AND SOUTH. A COLD FRONT ASSOCIATED
WITH THIS UPPER LEVEL ENERGY WILL LIKELY BE THE FOCUS FOR
PRECIPITATION CHANCES. CURRENT THINKING IS THIS FRONT WILL PASS
THROUGH THE OZARKS MONDAY NIGHT. HAVE RAISED POPS FOR THIS PERIOD
INTO THE HIGH CHANCE CATEGORY. MAY SEE SOME LINGERING SHOWERS INTO
TUESDAY ACROSS CENTRAL MISSOURI.
GLOBAL MODELS CONTINUE TO ADVERTISE A SECOND WAVE STRONGLY DIGGING
IN BEHIND THIS INITIAL WAVE AROUND MIDWEEK. THIS WAVE WILL LIKELY
BRING A STRONGER COLD FRONT ACROSS THE AREA...WITH 850 MB
TEMPERATURES PROGGED TO DIP INTO THE -5 TO -10 DEGREE CELSIUS
RANGE BY BOTH THE 12Z GFS AND ECMWF. THEREFORE CUT TEMPERATURES
STARTING AROUND MIDWEEK. IT IS QUITE POSSIBLE THAT WE SEE OUR
FIRST WIDESPREAD HARD FREEZE ACROSS THE REGION LATER NEXT WEEK. AM
NOT SEEING MUCH IF ANY PRECIPITATION THREAT LATER NEXT WEEK WITH
THE POSSIBLE EXCEPTION OF CENTRAL MISSOURI CLOSER TO THE TRACK OF
THAT SECOND WAVE.
SCHAUMANN
&&
.AVIATION...
FOR THE 22/0000Z KSGF/KJLN/KBBG TAFS...VFR CEILINGS ARE EXPECTED
AT TIMES AS A DISTURBANCE MOVES SOUTH AND EAST OF THE AREA.
AN UPPER LEVEL DISTURBANCE WILL MOVE W-E THROUGH MO LATE
SUNDAY...BUT WITH LIMITED MOISTURE...VFR CONDITIONS ARE EXPECTED TO
CONTINUE. DSA
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KEAX 212322
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
522 PM CST SAT NOV 21 2009
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
/346 PM CST SAT NOV 21 2009/
A WEAK WARM FRONT WAS LOCATED ACROSS THE SRN CWA WITH LOW LEVEL
MOISTURE LOCALLY POOLED NEAR THE BOUNDARY. THE BOUNDARY WILL SHIFT
QUICKLY NORTH AND DISSIPATE. AS PER FCST SOUNDINGS SUGGEST...THE
MOISTURE IS QUITE SHALLOW. THIS APPEARS REASONABLE GIVEN THE LOWER
DEWPOINTS WELL TO OUR SOUTH...IN AREAS WHERE DEEPER MIXING HAS
OCCURRED. GIVEN INTERVALS OF CLOUD COVER TONIGHT AND STRONGER SE
WINDS...DO NOT EXPECT WIDESPREAD DENSE FOG TONIGHT. GIVEN THE MIXY
NATURE OF THE SOUNDINGS JUST ABOVE THE SFC...STRATUS WOULD LIKELY BE
THE RESULT IF MOISTURE WAS DEEP ENOUGH. AT THE CURRENT TIME...MOIST
LAYER APPEARS INSUFFICIENT FOR STRATUS. THE ONLY EXCEPTION MAY BE
ACROSS THE NRN GRIDS TONIGHT WHERE LOW LEVEL MOISTURE IS A LITTLE
DEEPER.
WILL INTRODUCE PATCHY FOG FOR THE NRN GRIDS TONIGHT AND LET THE
EVENING SHIFT MAKE ANY REFINEMENTS BASED ON CURRENT TRENDS.
MOISTURE IMAGERY DEPICTS A SHORTWAVE MOVING INTO THE SRN AND CNTRL
ROCKIES. MODELS SUGGEST THAT THIS SHORTWAVE WILL EJECT ENE INTO THE
CWA SUN NIGHT. MOIST IS LIMITED WITH FORCING RATHER WEAK. CANNOT
RULE OUT A FEW SPRINKLES...BUT WILL NOT INTRODUCE AT THIS TIME.
OTHERWISE...MAIN CONCERN IS LATE MON AFTN AND MON NIGHT WHEN A STG
UPPER LEVEL LOW MOVES INTO THE PLAINS. THE MODELS HAVE A GENERAL
CONSENSUS IN MVG THE UPPER LEVEL LOW NR THE MO/IA BDR MON NGT AND
TUES WITH A STG WAVE MVG AROUND THE SRN PERIPHERY OF THE UPPER LEVEL
LOW. MUCH OF THE CWA IS IN THE FAVORABLE QUAD OF A 90KT H3 SPEED MAX
MON NGT WITH A MODEST PVU MAX ROTATING THROUGH MISSOURI. GIVEN THE
LOW STATIC STABILITY AND MODEST QG FORCING...HAVE INCREASED POPS FOR
LATE MON AFTN AND MON NGT. IN ADDITION...CANNOT RULE OUT AN ISOLATED
THUNDERSTORM GIVEN THE POTENTIAL FOR MUCAPES AROUND 100 J/KG.
DB
MEDIUM RANGE (TUESDAY THROUGH SATURDAY)...
OVERALL DECENT AGREEMENT AMONG ENSEMBLE GUIDANCE WITH RESPECT TO THE
UPPER AIR PATTERN THROUGH THE UPCOMING WORK WEEK. BY THE BEGINNING
OF THE WEEK...SHORT WAVE TROUGH IS EXPECTED DIVE ACROSS THE CENTRAL
CONUS BRINGING INCREASING PRECIPITATION CHANCES TO THE AREA.
DIFFERENCES IN THE EXACT LOCATION AND TIMING OF THIS FEATURE IS
EVIDENT AMONG VARIOUS SOLUTIONS...HOWEVER THE GENERAL IDEA IS
CERTAINLY CONSISTENT. BY TUESDAY...UPPER LOW WILL SLIDE ACROSS THE
CENTRAL PLAINS AND MIDWEST WITH LOCATION AND TIMING BY THIS TIME
FRAME KEY IN DETERMINING WHERE PRECIP IS MOST LIKELY AND WHEN ITS
EXPECTED TO PUSH EAST OF THE CWA. WILL KEEP HIGHEST RAIN CHANCES
ACROSS THE NORTHERN HALF OF THE CWA FOR TUESDAY...SLIDING ACTIVITY
EAST WITH TIME THROUGH TUESDAY NIGHT AND WEDNESDAY.
UPPER TROUGH AXIS APPEARS TO BE FAIRLY PROGRESSIVE WITH ADDITIONAL
SHORT WAVE ENERGY QUICK ON ITS HEELS. LINGERING PRECIP/CLOUD COVER
MAY BE EVIDENT THROUGH MIDWEEK AS SECONDARY SHORT WAVE TROUGH DIVES
SOUTH ON THE BACKSIDE OF DEPARTING SYSTEM. THIS WILL ALSO SERVE TO
BRING SOME SLIGHTLY COOLER AIR SOUTHWARD INTO THE MIDWESTERN STATES
BY WEDNESDAY AND THURSDAY. UPPER SHORT WAVE RIDGING WILL THEN
TRANSLATE ATOP THE REGION FOR THE LATTER PART OF THE WEEK AND INTO
THE WEEK BRINGING WARMER TEMPS.
DEROCHE
&&
.AVIATION...
FOR THE 00Z TAFS...WARM FRONT LIFTING NORTH ACROSS THE TAF SITES
THIS EVENING WILL BRING A PERIOD OF MVFR CIGS AND MAY ALSO HAVE SOME
MVFR FOG. ONCE THIS LIFTS NORTH BETWEEN 03 TO 04Z...PRESSURE
GRADIENT MAY BE ENOUGH TO PRECLUDE DENSE FOG OVERNIGHT...BUT WILL
KEEP THE MVFR VSBYS FROM THE PREVIOUS TAF GIVEN THE EXPECTED SMALL
TEMP DEWPOINT SPREAD. VFR CONDITIONS EXPECTED ON SUNDAY.
PC
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KLSX 212306
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
506 PM CST SAT NOV 21 2009
.DISCUSSION...
/330 PM CST SAT NOV 21 2009/
RATHER BENIGN WEATHER IS EXPECTED ACROSS THE REGION THRU MONDAY
WITH WEAK SFC RIDGING DOMINATING AND NUETRAL TO WEAK WAA FORECAST.
THE UPPER LOW CURRENTLY INVOF EXTREME ERN TX IS FORECAST TO REMAIN
WELL SOUTH OF THE AREA AS IT MOVES EWD INTO THE LOWER TN VALLEY ON
SUNDAY IN RESPONSE TO THE UPSTREAM KICKER SHORTWV MOVING THRU THE
GREAT BASIN ATTM. WITH LITTLE REAL OVERALL CHANGE IN THE AIR
MASS...TEMPERATURES WILL TO A DEGREE BE DEPENDENT ON THE AMOUNT OF
CLOUDS. MAKING THIS A LITTLE MORE CHALLENGING IS THE FACT THE
MODEL RH FIELDS HAVE BEEN RATHER POOR OVER THE LAST FEW DAYS IN
DEPICTING THE CLOUDS. I THINK FOR THE MOST PART THE CLOUDS TONIGHT
WILL DECREASE AND MOVE NNEWD AND THE GREATEST CLOUD COVER ON
SUNDAY WILL RESIDE IN THE WRN PORTION OF MO TOUCHING PORTIONS OF
CENTRAL AND NE MO AS WELL. THE FORECAST TEMPERATURE ARE A BLEND OF
PERSISTENCE AND THE WARMER SIDE OF THE MOS GUIDANCE SUITE.
THE MAIN EMPHASIS THIS FORECAST PERIOD WILL BE ON THE MID/UPPER
LOW FORECAST TO DEVELOP IN THE NORTHERN ROCKIES ON SUNDAY NIGHT
AND MOVE INTO THE MIDDLE MS VALLEY ON TUESDAY. THERE IS SOME
SPREAD ON THE LOW POSITION BY 00Z WED...BUT IT IS NOT EXCEEDINGLY
GREAT. A CONSENSUS POSITION WOULD BE INVOF SE IA...WITH THE LOW
EXITING INTO THE LOWER GREAT LAKES BY WEDNESDAY MORNING IN
RESPONSE TO THE NEXT DIGGING UPSTREAM SHORTWV TROF/UPPER LOW. IN
TERMS OF SENSIBLE WEATHER...WILL NEED TO KEEP AN EYE ON A LEAD
IMPULSE MOVING THRU THE AREA ON SUNDAY NIGHT/EARLY MON...WHICH HAS A
VERY LOW CHANCE OF BRINGING A SPRINKLE OR LGT SHOWER TO FAR NRN
SECTIONS. OTHERWISE PCPN CHANCES WILL RAMP UP MONDAY NIGHT INTO
TUESDAY WITH THE STG MID/UPPER LOW-TROF. LOW LEVEL MOISTURE WILL
BE RATHER DISMAL AHEAD OF THIS FEATURE AND THE ATTENDANT
CDFNT...HOWEVER LARGE SCALE ASCENT WILL BE QUITE ROBUST ALONG WITH
PLENTIFUL MID LEVEL MOISTURE...SUPPORTIVE OF A BAND OF RAIN WITH
CLOUD BASES IN THE MID LEVELS. ACCORDINGLY I HAVE BOOSTED POPS IN
THE WESTERN CWA ON MONDAY NIGHT...AND IN THE ERN CWA ON TUESDAY.
SOME GOOD CAA WILL OCCUR IN THE WAKE OF THE FRONT ALONG WITH
PROBABLY A DECENT AMOUNT OF STRATUS.
A CHILLY PERIOD WITH BELOW AVERAGE TEMPERATURES IS EXPECTED
WEDNESDAY INTO THURSDAY WITH THE AFOREMENTIONED SECONDARY SHRTWV
TROF/UPPER LOW DIGGING INTO THE REGION AND BRING A COLDER
REINFORCING SHOT OF COLD AIR. THERE HAD BEEN SOME DIFFERENCES IN
THE EXTENDED RANGE MODELS WITH RESPECT TO THIS SCENARIO...BUT WITH
THE NEW 12Z ECMWF RUN...THEY HAVE ALL COME ONBOARD. EXPECTING
MODERATION OF THE TEMPERATURES TO ABOVE NORMAL NEXT WEEKEND AS THE
TROF BEGINS EXITING THE EASTERN SEABOARD AND HEIGHTS RISE ALOFT.
GLASS
&&
.AVIATION...
/455 PM CST SAT NOV 21 2009/
FOR THE 00Z TAFS...LITTLE IF ANY CHANGES TO THE PREV TAF
FORECASTS. CLOUDS CURRENTLY OVER TAF SITES WILL CONTINUE TO MOVE
NWD AND BREAK UP DURING THE EVENING HOURS. WITH CLEAR SKIES
OVERNIGHT...EXPECT LGT FG TO DEVELOP AND PERSIST THRU MID MORNING
HOURS. AM A LITTLE UNCERTAIN AS TO EXACTLY WHEN FG WILL BECOME
MVFR...BUT HAVE PUSHED IT BACK A COUPLE OF HOURS AS CLOUDS PERSIST
OVER THE AREA. IF CLOUDS FAIL TO BREAK UP...FG DEVELOPMENT MAY NOT
OCCUR UNTIL MUCH LATER...NEAR 12Z. OTHERWISE...SUNDAY SHUD BE SKC
WITH LIGHT SE TO ESE WINDS.
TILLY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 212146
AFDLSX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
346 PM CST SAT NOV 21 2009
.DISCUSSION...
/330 PM CST SAT NOV 21 2009/
RATHER BENIGN WEATHER IS EXPECTED ACROSS THE REGION THRU MONDAY
WITH WEAK SFC RIDGING DOMINATING AND NUETRAL TO WEAK WAA FORECAST.
THE UPPER LOW CURRENTLY INVOF EXTREME ERN TX IS FORECAST TO REMAIN
WELL SOUTH OF THE AREA AS IT MOVES EWD INTO THE LOWER TN VALLEY ON
SUNDAY IN RESPONSE TO THE UPSTREAM KICKER SHORTWV MOVING THRU THE
GREAT BASIN ATTM. WITH LITTLE REAL OVERALL CHANGE IN THE AIR
MASS...TEMPERATURES WILL TO A DEGREE BE DEPENDENT ON THE AMOUNT OF
CLOUDS. MAKING THIS A LITTLE MORE CHALLENGING IS THE FACT THE
MODEL RH FIELDS HAVE BEEN RATHER POOR OVER THE LAST FEW DAYS IN
DEPICTING THE CLOUDS. I THINK FOR THE MOST PART THE CLOUDS TONIGHT
WILL DECREASE AND MOVE NNEWD AND THE GREATEST CLOUD COVER ON
SUNDAY WILL RESIDE IN THE WRN PORTION OF MO TOUCHING PORTIONS OF
CENTRAL AND NE MO AS WELL. THE FORECAST TEMPERATURE ARE A BLEND OF
PERSISTENCE AND THE WARMER SIDE OF THE MOS GUIDANCE SUITE.
THE MAIN EMPHASIS THIS FORECAST PERIOD WILL BE ON THE MID/UPPER
LOW FORECAST TO DEVELOP IN THE NORTHERN ROCKIES ON SUNDAY NIGHT
AND MOVE INTO THE MIDDLE MS VALLEY ON TUESDAY. THERE IS SOME
SPREAD ON THE LOW POSITION BY 00Z WED...BUT IT IS NOT EXCEEDINGLY
GREAT. A CONSENSUS POSITION WOULD BE INVOF SE IA...WITH THE LOW
EXITING INTO THE LOWER GREAT LAKES BY WEDNESDAY MORNING IN
RESPONSE TO THE NEXT DIGGING UPSTREAM SHORTWV TROF/UPPER LOW. IN
TERMS OF SENSIBLE WEATHER...WILL NEED TO KEEP AN EYE ON A LEAD
IMPULSE MOVING THRU THE AREA ON SUNDAY NIGHT/EARLY MON...WHICH HAS A
VERY LOW CHANCE OF BRINGING A SPRINKLE OR LGT SHOWER TO FAR NRN
SECTIONS. OTHERWISE PCPN CHANCES WILL RAMP UP MONDAY NIGHT INTO
TUESDAY WITH THE STG MID/UPPER LOW-TROF. LOW LEVEL MOISTURE WILL
BE RATHER DISMAL AHEAD OF THIS FEATURE AND THE ATTENDANT
CDFNT...HOWEVER LARGE SCALE ASCENT WILL BE QUITE ROBUST ALONG WITH
PLENTIFUL MID LEVEL MOISTURE...SUPPORTIVE OF A BAND OF RAIN WITH
CLOUD BASES IN THE MID LEVELS. ACCORDINGLY I HAVE BOOSTED POPS IN
THE WESTERN CWA ON MONDAY NIGHT...AND IN THE ERN CWA ON TUESDAY.
SOME GOOD CAA WILL OCCUR IN THE WAKE OF THE FRONT ALONG WITH
PROBABLY A DECENT AMOUNT OF STRATUS.
A CHILLY PERIOD WITH BELOW AVERAGE TEMPERATURES IS EXPECTED
WEDNESDAY INTO THURSDAY WITH THE AFOREMENTIONED SECONDARY SHRTWV
TROF/UPPER LOW DIGGING INTO THE REGION AND BRING A COLDER
REINFORCING SHOT OF COLD AIR. THERE HAD BEEN SOME DIFFERENCES IN
THE EXTENDED RANGE MODELS WITH RESPECT TO THIS SCENARIO...BUT WITH
THE NEW 12Z ECMWF RUN...THEY HAVE ALL COME ONBOARD. EXPECTING
MODERATION OF THE TEMPERATURES TO ABOVE NORMAL NEXT WEEKEND AS THE
TROF BEGINS EXITING THE EASTERN SEABOARD AND HEIGHTS RISE ALOFT.
GLASS
&&
.AVIATION...
/1043 AM CST SAT NOV 21 2009/
FOR THE 18Z TAFS...VFR LOW-MID LEVEL CLOUDS...4500-9000 FT SHOULD
CONTINUE TO PUSH NWD THRU THE TAF SITES THIS AFTN AND INTO TGT.
MODELS DEPICT HIGH RH BETWEEN 850-700 MB IN HEIGHT THIS AFTN WITH
THIS LAYER GRADUALLY DRYING OUT TGT. CLOUD COVER MAY BECOME PREDOMINATELY
SCT BY LATE TGT AND SUN MRNG. WITH LESS CLOUD COVER LATE TGT AND
EARLY SUN MRNG THERE SHOULD BE LIGHT FOG DURING THIS TIME PERIOD
WITH VSBYS DOWN TO AROUND 3-5SM BR. AN E-SELY SFC WND SHOULD
CONTINUE THRU THE TAF FORECAST PERIOD AS THE TAF SITES WILL BE ON
THE WRN PERIPHERY OF THE SFC RDG CENTERED OVER THE GREAT LAKES AND
OHIO VALLEY REGIONS.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KEAX 212146
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
346 PM CST SAT NOV 21 2009
.DISCUSSION...
A WEAK WARM FRONT WAS LOCATED ACROSS THE SRN CWA WITH LOW LEVEL
MOISTURE LOCALLY POOLED NEAR THE BOUNDARY. THE BOUNDARY WILL SHIFT
QUICKLY NORTH AND DISSIPATE. AS PER FCST SOUNDINGS SUGGEST...THE
MOISTURE IS QUITE SHALLOW. THIS APPEARS REASONABLE GIVEN THE LOWER
DEWPOINTS WELL TO OUR SOUTH...IN AREAS WHERE DEEPER MIXING HAS
OCCURRED. GIVEN INTERVALS OF CLOUD COVER TONIGHT AND STRONGER SE
WINDS...DO NOT EXPECT WIDESPREAD DENSE FOG TONIGHT. GIVEN THE MIXY
NATURE OF THE SOUNDINGS JUST ABOVE THE SFC...STRATUS WOULD LIKELY BE
THE RESULT IF MOISTURE WAS DEEP ENOUGH. AT THE CURRENT TIME...MOIST
LAYER APPEARS INSUFFICIENT FOR STRATUS. THE ONLY EXCEPTION MAY BE
ACROSS THE NRN GRIDS TONIGHT WHERE LOW LEVEL MOISTURE IS A LITTLE DEEPER.
WILL INTRODUCE PATCHY FOG FOR THE NRN GRIDS TONIGHT AND LET THE
EVENING SHIFT MAKE ANY REFINEMENTS BASED ON CURRENT TRENDS.
MOISTURE IMAGERY DEPICTS A SHORTWAVE MOVING INTO THE SRN AND CNTRL
ROCKIES. MODELS SUGGEST THAT THIS SHORTWAVE WILL EJECT ENE INTO THE
CWA SUN NIGHT. MOIST IS LIMITED WITH FORCING RATHER WEAK. CANNOT
RULE OUT A FEW SPRINKLES...BUT WILL NOT INTRODUCE AT THIS TIME.
OTHERWISE...MAIN CONCERN IS LATE MON AFTN AND MON NIGHT WHEN A STG
UPPER LEVEL LOW MOVES INTO THE PLAINS. THE MODELS HAVE A GENERAL
CONSENSUS IN MVG THE UPPER LEVEL LOW NR THE MO/IA BDR MON NGT AND
TUES WITH A STG WAVE MVG AROUND THE SRN PERIPHERY OF THE UPPER LEVEL
LOW. MUCH OF THE CWA IS IN THE FAVORABLE QUAD OF A 90KT H3 SPEED MAX
MON NGT WITH A MODEST PVU MAX ROTATING THROUGH MISSOURI. GIVEN THE
LOW STATIC STABILITY AND MODEST QG FORCING...HAVE INCREASED POPS FOR
LATE MON AFTN AND MON NGT. IN ADDITION...CANNOT RULE OUT AN ISOLATED
THUNDERSTORM GIVEN THE POTENTIAL FOR MUCAPES AROUND 100 J/KG.
DB
MEDIUM RANGE (TUESDAY THROUGH SATURDAY)...
OVERALL DECENT AGREEMENT AMONG ENSEMBLE GUIDANCE WRT TO THE UPPER
AIR PATTERN THROUGH THE UPCOMING WORK WEEK. BY THE BEGINNING OF THE
WEEK...SHORT WAVE TROUGH IS EXPECTED DIVE ACROSS THE CENTRAL CONUS
BRINGING INCREASING PRECIPITATION CHANCES TO THE AREA. DIFFERENCES
IN THE EXACT LOCATION AND TIMING OF THIS FEATURE IS EVIDENT AMONG
VARIOUS SOLUTIONS...HOWEVER THE GENERAL IDEA IS CERTAINLY
CONSISTENT. BY TUESDAY...UPPER LOW WILL SLIDE ACROSS THE CENTRAL
PLAINS AND MIDWEST WITH LOCATION AND TIMING BY THIS TIME FRAME KEY
IN DETERMINING WHERE PRECIP IS MOST LIKELY AND WHEN ITS EXPECTED TO
PUSH EAST OF THE CWA. WILL KEEP HIGHEST RAIN CHANCES ACROSS THE
NORTHERN HALF OF THE CWA FOR TUESDAY...SLIDING ACTIVITY EAST WITH
TIME THROUGH TUESDAY NIGHT AND WEDNESDAY.
UPPER TROUGH AXIS APPEARS TO BE FAIRLY PROGRESSIVE WITH ADDITIONAL
SHORT WAVE ENERGY QUICK ON ITS HEELS. LINGERING PRECIP/CLOUD COVER
MAY BE EVIDENT THROUGH MIDWEEK AS SECONDARY SHORT WAVE TROUGH DIVES
SOUTH ON THE BACKSIDE OF DEPARTING SYSTEM. THIS WILL ALSO SERVE TO
BRING SOME SLIGHTLY COOLER AIR SOUTHWARD INTO THE MIDWESTERN STATES
BY WEDNESDAY AND THURSDAY. UPPER SHORT WAVE RIDGING WILL THEN
TRANSLATE ATOP THE REGION FOR THE LATTER PART OF THE WEEK AND INTO
THE WEEK BRINGING WARMER TEMPS.
DEROCHE
&&
.AVIATION...
FOR THE 18Z TAFS...A VFR STRATOCU CLOUD DECK PREVAILED ACR THE TERMINALS
EARLY THIS AFTN. HOWEVER...A MVFR STRATUS DECK WAS NOTED IN SERN
KS...AHEAD OF A WEAK WARM FRONT. IT IS DIFFICULT TO DETERMINE THE ERN
EDGE OF THE CLOUD DECK DUE TO THE HIGHER STRATOCU DECK. BOTH THE GFS
AND NAM SUGGEST THAT THE MVFR CLOUD DECK MAY CLIP THE TERMINALS LATE
THIS AFTN. CONFIDENCE IS NOT HIGH. REGARDLESS...THE MVFR CLOUD DECK
WILL SHIFT NORTH TONIGHT AND BE REPLACED WITH A MVFR STRATOCU/AC SCT-
BKN DECK. MAY SEE PERIODS OF MVFR FOG LATE TONIGHT AT THE
TERMINALS...BUT GIVEN CLOUD COVER AND MODEST WINDS...IFR FOG IS NOT
EXPECTED. OTHERWISE...ANY MVFR WILL BURN OFF RAPIDLY AFT SUNRISE WITH
VFR CONDITIONS FOR SUN MORNING.
DB
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE. KS...NONE. &&
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KSGF 212052
AFDSGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
252 PM CST SAT NOV 21 2009
.DISCUSSION...
THE MAIN FORECAST FOCUS WAS ON EARLY NEXT WEEK AS THIS WILL BE OUR
NEXT SHOT AT PRECIPITATION. THIS WILL BE THE START OF A LARGE
SCALE PATTERN CHANGE AS THE UPPER LEVEL FLOW BECOMES MORE
AMPLIFIED AND NORTHWESTERLY ACROSS THE CENTRAL UNITED STATES. THIS
WILL RESULT IN BELOW NORMAL TEMPERATURES FOR THE MID TO LATE WEEK
PERIOD.
A RATHER FLAT AND PROGRESSIVE UPPER LEVEL PATTERN WILL PERSIST FOR
THE REMAINDER OF THIS WEEKEND. WE WILL SEE ONE WEAK SHORT WAVE
TROUGH CROSS THE REGION SUNDAY NIGHT...BUT MOISTURE WILL BE VERY
LIMITED. COULD SEE A SHOWER ACROSS SOUTHEAST MISSOURI...BUT THAT
WOULD BE ABOUT IT. STUCK VERY CLOSE TO MAV/MET BLEND FOR
TEMPERATURES FOR THE REMAINDER OF THE WEEKEND.
THE PATTERN WILL SLOWLY BECOME MORE AMPLIFIED NEXT WEEK. DIGGING
POTENTIAL WILL INCREASE THROUGHOUT THE WEEK FOR ANY SHORT WAVE
ENERGY ORIGINATING FROM THE PACIFIC NORTHWEST OR WESTERN CANADA.
THE FIRST SUCH WAVE WILL MOVE INTO THE NORTHERN AND CENTRAL
PLAINS FROM LATE MONDAY INTO TUESDAY. WE WILL SEE SOME INCREASE IN
LOW LEVEL MOISTURE AHEAD OF THIS FEATURE AS LOW LEVEL WINDS
INCREASE OUT OF THE SOUTHEAST AND SOUTH. A COLD FRONT ASSOCIATED
WITH THIS UPPER LEVEL ENERGY WILL LIKELY BE THE FOCUS FOR
PRECIPITATION CHANCES. CURRENT THINKING IS THIS FRONT WILL PASS
THROUGH THE OZARKS MONDAY NIGHT. HAVE RAISED POPS FOR THIS PERIOD
INTO THE HIGH CHANCE CATEGORY. MAY SEE SOME LINGERING SHOWERS INTO
TUESDAY ACROSS CENTRAL MISSOURI.
GLOBAL MODELS CONTINUE TO ADVERTISE A SECOND WAVE STRONGLY DIGGING
IN BEHIND THIS INITIAL WAVE AROUND MIDWEEK. THIS WAVE WILL LIKELY
BRING A STRONGER COLD FRONT ACROSS THE AREA...WITH 850 MB
TEMPERATURES PROGGED TO DIP INTO THE -5 TO -10 DEGREE CELSIUS
RANGE BY BOTH THE 12Z GFS AND ECMWF. THEREFORE CUT TEMPERATURES
STARTING AROUND MIDWEEK. IT IS QUITE POSSIBLE THAT WE SEE OUR
FIRST WIDESPREAD HARD FREEZE ACROSS THE REGION LATER NEXT WEEK. AM
NOT SEEING MUCH IF ANY PRECIPITATION THREAT LATER NEXT WEEK WITH
THE POSSIBLE EXCEPTION OF CENTRAL MISSOURI CLOSER TO THE TRACK OF
THAT SECOND WAVE.
SCHAUMANN
&&
.AVIATION...
FOR THE 18Z KSGF...KJLN AND KBBG TAFS...A BRIEF PERIOD OF HIGH END
MVFR CONDITIONS ARE EXPECTED AT THE KJLN TAF SITE EARLY THIS
AFTERNOON. OTHERWISE VFR CONDITIONS EXPECTED THROUGH SUNDAY MORNING.
THE LOW LEVEL CLOUD DECK OVER THE TAF STIES LATE THIS MORNING...WILL
DISSIPATE BY EARLY EVENING...WITH LIGHT SOUTHEAST WINDS AND HIGH
CLOUDS EXPECTED OVERNIGHT.
WISE
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KEAX 211726
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1126 AM CST SAT NOV 21 2009
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
DENSE FOG WILL BE THE SHORT TERM PROBLEM AS MUCH OF NORTHERN MO IS
EXPERIENCING VISIBILITIES A QUARTER OF A MILE OR LESS. CONDITIONS
WILL IMPROVE BY LATE MORNING AS THE FOG LIFTS TO FORM A STRATUS
DECK. SATELLITE IMAGERY ALSO SHOWS A LOW CLOUD DECK TIED TO DEEPER
MOISTURE ADVECTING NORTH FROM TX/OK/AR. A WEAK W-E SURFACE RIDGE
CUTTING THROUGH THE CENTER OF THE CWA DIVIDES DENSE FOG TO THE NORTH
AND THE LOW CLOUDS TO THE SOUTH. THIS RIDGE AXIS IS EXPECTED TO
FALL APART TO DAY AS SURFACE TROUGHING OVER THE HIGH PLAINS PUSHES
EAST AND DISPLACES THE RIDGE...THUS ALLOWING THE LOW CLOUDS TO
SPREAD INTO NORTHERN MO. SPECIAL FOG LOOP SUGGESTS THE DENSE FOG IS
RATHER SHALLOW AND LIKELY TO BURN OFF BY MID MORNING. BY THIS TIME
THE LOW CLOUDS SHOULD BE WORKING THEIR WAY INTO NORTHERN MO. THE NET
EFFECT IS SUNSHINE COULD BE IN SHORT SUPPLY TODAY. MAX TEMPERATURES
REFLECT THIS IDEA.
LATEST SREF SURFACE VISIBILITY PROBABILITY PROG WHICH CORRECTLY
FORECAST THIS MORNINGS DENSE FOG IS SIGNALING THE POTENTIAL FOR
DENSE FOG FOR TONIGHT OVER THE NW 1/4 OF THE CWA. THIS WOULD FIT
WITH THE STRATUS/DRIZZLE NOW OVER CENTRAL OK ADVECTING NNE ACROSS KS
AND EVENTUALLY NW MO.
A COUPLE OF SHORTWAVES WILL PASS THROUGH THE PLAINS AND MID MO
VALLEY DURING THE SUNDAY-TUESDAY TIME FRAME. THE INITIAL SHORTWAVE
MOVING INTO THE CENTRAL HIGH PLAINS ON SUNDAY WILL MOST LIKELY
WEAKEN AS IT IS CAUGHT IN BETWEEN A STRONGER UPSTREAM SHORTWAVE
DIVING INTO THE ROCKIES AND THE UPPER WAVE NOW OVER EASTERN TX. THIS
INITIAL SHORTWAVE WILL LIKELY ONLY HAVE SOME MID/HIGH CLOUDS WITH IT
SO PRECIPITATION IS NOT LIKELY TO FALL IN OUR CWA.
THE SECOND SYSTEM LOOKS LIKE IT WILL BE A DIFFERENT ANIMAL AS IT
DIVES SOUTHEAST WITH A NEGATIVE TILT. NAM/GFS/ECMWF/SREF/GEM ALL
CLOSE OFF THE UPPER CIRCULATION MONDAY NIGHT. THERE IS DECENT MODEL
CONSISTENCY IN THE PLACEMENT OF THE UPPER LOW AND GENERAL DEPICTION
OF THE UPPER WAVE. EARLIER GFS RUNS WERE TOO PROGRESSIVE WITH THE
SURFACE COLD FRONT AND THE 06Z MODEL RUN IS NOW MORE IN LINE WITH
THE NAM/ECMWF. WITH INCREASING CONFIDENCE ON EVOLUTION OF THIS
SYSTEM HAVE INCREASED POPS FOR MONDAY NIGHT/TUESDAY. ANOTHER MODEL
RUN OR TWO SHOWING THIS SAME CONSISTENCY SHOULD ALLOW LATER SHIFTS
TO RAISE POPS TO LIKELY.
MJ
&&
.AVIATION...
FOR THE 18Z TAFS...A VFR STRATOCU CLOUD DECK PREVAILED ACR THE TERMINALS
EARLY THIS AFTN. HOWEVER...A MVFR STRATUS DECK WAS NOTED IN SERN
KS...AHEAD OF A WEAK WARM FRONT. IT IS DIFFICULT TO DETERMINE THE ERN
EDGE OF THE CLOUD DECK DUE TO THE HIGHER STRATOCU DECK. BOTH THE GFS
AND NAM SUGGEST THAT THE MVFR CLOUD DECK MAY CLIP THE TERMINALS LATE
THIS AFTN. CONFIDENCE IS NOT HIGH. REGARDLESS...THE MVFR CLOUD DECK
WILL SHIFT NORTH TONIGHT AND BE REPLACED WITH A MVFR STRATOCU/AC SCT-
BKN DECK. MAY SEE PERIODS OF MVFR FOG LATE TONIGHT AT THE
TERMINALS...BUT GIVEN CLOUD COVER AND MODEST WINDS...IFR FOG IS NOT
EXPECTED. OTHERWISE...ANY MVFR WILL BURN OFF RAPIDLY AFT SUNRISE WITH
VFR CONDITIONS FOR SUN MORNING.
DB
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE. KS...NONE. &&
$$
000
FXUS63 KSGF 211720
AFDSGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1120 AM CST SAT NOV 21 2009
...UPDATE TO AVIATION...
.DISCUSSION...
FORECAST CHALLENGES DEAL PRIMARILY WITH TEMPERATURES THROUGH THE
WEEKEND...FOLLOWED BY TIMING OF NEXT FROPA THE EARLY PART OF NEXT WEEK.
CURRENTLY...SURFACE HIGH CENTERED OVER ILLINOIS THIS MORNING
GIVING US AN EASTERLY TO SOUTHEASTERLY WIND FLOW. 11-3.9U SATELLITE
IMAGERY SHOWING STRATUS DECK STILL HANGING ACROSS SOUTHERN
MISSOURI INTO NORTHERN ARKANSAS. TEMPERATURES REMAIN QUITE WARM
WITH LOW 50S ACROSS SOUTHERN MISSOURI AND MID 40S ACROSS CENTRAL
MISSOURI AT THIS TIME. OUR NEXT STORM SYSTEM MOVING INTO THE
ROCKIES THIS MORNING WITH RIDGING FROM NEW MEXICO NORTH INTO NORTH
DAKOTA OUT AHEAD OF THIS SYSTEM. UPPER CIRCULATION CONTINUES OVER
NORTHERN TEXAS ON WATER VAPOR IMAGERY WITH DRY SLOTTING OVER MOST
OF THE CWA.
FOR THIS WEEKEND...GENERALLY FOLLOWED MET GUIDANCE ON TEMPERATURES
AS IT HAS BEEN DOING VERY WELL THE PAST COUPLE DAYS. SHOULD SEE
TEMPERATURES ONCE AGAIN IN THE LOW 60S AS THE STRATUS DECK BREAKS
UP...DESPITE 850/925MB TEMPERATURES BEING A LITTLE COOLER TODAY
OVER YESTERDAY. THIS COOLING SHOULD BE OFFSET BY SUNSHINE THIS
AFTERNOON. UPPER LOW OVER TEXAS FORECAST TO TRACK ACROSS NORTHERN
LOUISIANA THROUGH THE DAY...EFFECTIVELY CUTTING OFF ANY GULF
MOISTURE RETURN. LOOKS DRY AND WARM THROUGH THE WEEKEND BEFORE OUR
NEXT SYSTEM APPROACHES EARLY NEXT WEEK. CONTINUED FOLLOWING
MET/WRF GUIDANCE ON TEMPERATURES. GFS DOES SHOW A WEAK SHORTWAVE
PUSHING THROUGH THE AREA SUNDAY AFTERNOON...BUT WITH NO GULF
MOISTURE RETURN...KEPT THE FORECAST DRY.
THE 00Z GFS STARTING TO COME MORE IN LINE WITH THE ECMWF ON
POSITIONING OF UPPER LOW AND ASSOCIATED COLD FRONT MONDAY
AFTERNOON INTO TUESDAY. STILL A LITTLE FURTHER NORTH WITH THE LOW
CENTER TRACKING ACROSS IOWA..WHILE ECMWF TRACK IT MORE ACROSS
NORTH CENTRAL MISSOURI MONDAY NIGHT. BOTH SHOW A FAIRLY STRONG
COLD FRONT PUSHING THROUGH MONDAY NIGHT INTO TUESDAY AND HAVE
CONTINUED CHANCE POPS FOR THIS TIME FRAME. PRETTY GOOD SHOT OF COLD
AIR BEHIND THE FRONT AS WELL WITH 850MB TEMPERATURES FALLING TO
-4C TUESDAY AFTERNOON. A SECONDARY SHORTWAVE WITH ANOTHER SHOT OF
COLD AIR LOOKS TO BE ON TAP FOR WEDNESDAY WITH 850MB TEMPERATURES
FALLING TO -6C...SO LOOKS LIKE TUESDAY THROUGH THURSDAY WILL
PROBABLY SEE TEMPERATURES BELOW NORMAL BASED ON BETTER AGREEMENT
BETWEEN THE TWO MODELS. WILL MOST LIKELY SEE OUR FIRST REAL FREEZE
OF THE SEASON THURSDAY MORNING WITH LOWS IN THE UPPER 20S AREA WIDE.
CLAYCOMB
&&
.AVIATION...
FOR THE 18Z KSGF...KJLN AND KBBG TAFS...A BRIEF PERIOD OF HIGH END
MVFR CONDITIONS ARE EXPECTED AT THE KJLN TAF SITE EARLY THIS
AFTERNOON. OTHERWISE VFR CONDITIONS EXPECTED THROUGH SUNDAY MORNING.
THE LOW LEVEL CLOUD DECK OVER THE TAF STIES LATE THIS MORNING...WILL
DISSIPATE BY EARLY EVENING...WITH LIGHT SOUTHEAST WINDS AND HIGH
CLOUDS EXPECTED OVERNIGHT.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KLSX 211703
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1103 AM CST SAT NOV 21 2009
.DISCUSSION...
/320 AM CST SAT NOV 21 2009/
MAIN CONCERNS DEAL WITH EXTENT OF FOG THIS MORNING AND CHANCES OF
RAIN EARLY NEXT WEEK.
SOLID BAND OF CLOUDS OVER THE CWA LAST EVENING HAS BROKEN UP THE
PAST FEW HOURS. THIS COMBINED WITH THE LIGHT WINDS CAUSED BY OUR
CLOSE PROXIMITY TO CENTER OF SFC HIGH PRESSURE OVER NRN INDIANA
HAS CAUSED AREAS OF FOG. FEWER OB SITES ARE REPORTING DENSE
FOG...PRIMARILY IN LOW LYING AREAS LIKE CPS/SUS...THAN YESTERDAY
MORNING. WILL INCLUDE AREAS OF FOG IN THE FORECAST AND THE PATCHY
DENSE FOG IN NOWCASTS. LIKE YESTERDAY...FOG SHOULD DISSIPATE BY
MID MORNING. TIME CROSS SECTIONS ARE SHOWING HIGH RH VALUES
THROUGH TONIGHT BETWEEN 5-8KFT AND A LARGE AREA OF CLOUDS OVER
CURRENTLY OVER WRN AND SRN MO IS MOVING NEWD INTO THE CWA. HAVE
MOSTLY CLOUDY GOING OVER MOST OF THE CWA TODAY WITH CLEARING
TONIGHT. DRY WEATHER WILL DOMINATE THROUGH TOMORROW AS AREA LIES
UNDER NEUTRAL VERTICAL MOTION OR SUBSIDENCE BENEATH BUILDING UPPER
RIDGE.
AGREEMENT IN MODELS BEGINS TO DIVERGE BY EARLY NEXT WEEK WHEN THE
NAM SLIGHTLY TRAILS THE OTHER MODELS WITH A WEAK SHORTWAVE TROUGH
THAT CROSSES MO/IL ON SUNDAY NIGHT. THERE WILL NOT BE ENOUGH LARGE
SCALE ASCENT OR MOISTURE WITH THIS SYSTEM TO INCLUDE A CHANCE OF
RAIN AT THIS TIME. THERE IS ALSO SOME DISPARITY WITH THE TIMING OF
A MUCH STRONGER CLOSED LOW AND ACCOMPANYING COLD FRONT WITH THE
NAM SHOWING A FROPA ABOUT 6-12 HOURS LATER ON TUESDAY THAN THE
GFS. THE CANADIAN GEM SUPPORTS THE FASTER GFS AND THE ECMWF FAVORS
THE NAM SO USED A COMBINATION OF ALL OF THEM...USING A BLEND OF
THE SREF MEAN AND THE GFS MOS FOR THE MASS FIELDS. THIS CALLS FOR
GOING DRY THROUGH MONDAY WITH A CHANCE POPS WITH FROPA MONDAY
NIGHT AND TUESDAY.
WENT CLOSER TO THE COOLER GFS MOS FOR TEMPS TODAY GIVEN EXPECTED
MOSTLY CLOUDY SKIES AND LIGHT SELY WINDS. WENT TOWARD THE WARMER
SIDE OF GUIDANCE SUNDAY MONDAY AS I EXPECT MORE SUN AND WINDS
VEERING SLY AHEAD STORM SYSTEM EARLY NEXT WEEK.
BRITT
&&
.AVIATION...
/1043 AM CST SAT NOV 21 2009/
FOR THE 18Z TAFS...VFR LOW-MID LEVEL CLOUDS...4500-9000 FT SHOULD
CONTINUE TO PUSH NWD THRU THE TAF SITES THIS AFTN AND INTO TGT.
MODELS DEPICT HIGH RH BETWEEN 850-700 MB IN HEIGHT THIS AFTN WITH
THIS LAYER GRADUALLY DRYING OUT TGT. CLOUD COVER MAY BECOME PREDOMINATELY
SCT BY LATE TGT AND SUN MRNG. WITH LESS CLOUD COVER LATE TGT AND
EARLY SUN MRNG THERE SHOULD BE LIGHT FOG DURING THIS TIME PERIOD
WITH VSBYS DOWN TO AROUND 3-5SM BR. AN E-SELY SFC WND SHOULD
CONTINUE THRU THE TAF FORECAST PERIOD AS THE TAF SITES WILL BE ON
THE WRN PERIPHERY OF THE SFC RDG CENTERED OVER THE GREAT LAKES AND
OHIO VALLEY REGIONS.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 211146
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
546 AM CST SAT NOV 21 2009
.DISCUSSION...
/320 AM CST SAT NOV 21 2009/
MAIN CONCERNS DEAL WITH EXTENT OF FOG THIS MORNING AND CHANCES OF
RAIN EARLY NEXT WEEK.
SOLID BAND OF CLOUDS OVER THE CWA LAST EVENING HAS BROKEN UP THE
PAST FEW HOURS. THIS COMBINED WITH THE LIGHT WINDS CAUSED BY OUR
CLOSE PROXIMITY TO CENTER OF SFC HIGH PRESSURE OVER NRN INDIANA
HAS CAUSED AREAS OF FOG. FEWER OB SITES ARE REPORTING DENSE
FOG...PRIMARILY IN LOW LYING AREAS LIKE CPS/SUS...THAN YESTERDAY
MORNING. WILL INCLUDE AREAS OF FOG IN THE FORECAST AND THE PATCHY
DENSE FOG IN NOWCASTS. LIKE YESTERDAY...FOG SHOULD DISSIPATE BY
MID MORNING. TIME CROSS SECTIONS ARE SHOWING HIGH RH VALUES
THROUGH TONIGHT BETWEEN 5-8KFT AND A LARGE AREA OF CLOUDS OVER
CURRENTLY OVER WRN AND SRN MO IS MOVING NEWD INTO THE CWA. HAVE
MOSTLY CLOUDY GOING OVER MOST OF THE CWA TODAY WITH CLEARING
TONIGHT. DRY WEATHER WILL DOMINATE THROUGH TOMORROW AS AREA LIES
UNDER NEUTRAL VERTICAL MOTION OR SUBSIDENCE BENEATH BUILDING UPPER
RIDGE.
AGREEMENT IN MODELS BEGINS TO DIVERGE BY EARLY NEXT WEEK WHEN THE
NAM SLIGHTLY TRAILS THE OTHER MODELS WITH A WEAK SHORTWAVE TROUGH
THAT CROSSES MO/IL ON SUNDAY NIGHT. THERE WILL NOT BE ENOUGH LARGE
SCALE ASCENT OR MOISTURE WITH THIS SYSTEM TO INCLUDE A CHANCE OF
RAIN AT THIS TIME. THERE IS ALSO SOME DISPARITY WITH THE TIMING OF
A MUCH STRONGER CLOSED LOW AND ACCOMPANYING COLD FRONT WITH THE
NAM SHOWING A FROPA ABOUT 6-12 HOURS LATER ON TUESDAY THAN THE
GFS. THE CANADIAN GEM SUPPORTS THE FASTER GFS AND THE ECMWF FAVORS
THE NAM SO USED A COMBINATION OF ALL OF THEM...USING A BLEND OF
THE SREF MEAN AND THE GFS MOS FOR THE MASS FIELDS. THIS CALLS FOR
GOING DRY THROUGH MONDAY WITH A CHANCE POPS WITH FROPA MONDAY
NIGHT AND TUESDAY.
WENT CLOSER TO THE COOLER GFS MOS FOR TEMPS TODAY GIVEN EXPECTED
MOSTLY CLOUDY SKIES AND LIGHT SELY WINDS. WENT TOWARD THE WARMER
SIDE OF GUIDANCE SUNDAY MONDAY AS I EXPECT MORE SUN AND WINDS
VEERING SLY AHEAD STORM SYSTEM EARLY NEXT WEEK.
BRITT
&&
.AVIATION...
/540 AM CST SAT NOV 21 2009/
FOR THE 12Z TAFS...
PRIMARY CONCERN ONCE AGAIN THIS MORNING IS FOG...BUT THE FOG IS
NEITHER AS WIDESPREAD OR AS DENSE THIS MORNING AS YESTERDAY. MOST
OF THE FOG IS MVFR...WITH INTERMITTENT DROPS BELOW 3 MILES. A FEW
SPOTS...PRIMARILY IN RIVER VALLEYS...HAVE REPORTED LIFR CONDITIONS.
I EXPECT THIS FOG TO DISSIPATE BETWEEN 13Z AND 14Z AFTER SUNRISE.
SOME OF THE THICKER STUFF COULD HANG AROUND AS LONG AS 15Z. AFTER
15Z I EXPECT VFR CONDITIONS TO PREVAIL WITH SCT-BKN CLOUDS AROUND
6000FT AS AN UPPER LEVEL DISTURBANCE CHURNS SLOWLY OVER THE
TEXAS/LOUISIANA GULF COAST TODAY BRINGING MID-UPPER LEVEL MOISTURE
STREAMING UP INTO THE MID-MISSISSIPPI VALLEY REGION.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KEAX 211141
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
541 AM CST SAT NOV 21 2009
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
DENSE FOG WILL BE THE SHORT TERM PROBLEM AS MUCH OF NORTHERN MO IS
EXPERIENCING VISIBILITIES A QUARTER OF A MILE OR LESS. CONDITIONS
WILL IMPROVE BY LATE MORNING AS THE FOG LIFTS TO FORM A STRATUS
DECK. SATELLITE IMAGERY ALSO SHOWS A LOW CLOUD DECK TIED TO DEEPER
MOISTURE ADVECTING NORTH FROM TX/OK/AR. A WEAK W-E SURFACE RIDGE
CUTTING THROUGH THE CENTER OF THE CWA DIVIDES DENSE FOG TO THE NORTH
AND THE LOW CLOUDS TO THE SOUTH. THIS RIDGE AXIS IS EXPECTED TO
FALL APART TO DAY AS SURFACE TROUGHING OVER THE HIGH PLAINS PUSHES
EAST AND DISPLACES THE RIDGE...THUS ALLOWING THE LOW CLOUDS TO
SPREAD INTO NORTHERN MO. SPECIAL FOG LOOP SUGGESTS THE DENSE FOG IS
RATHER SHALLOW AND LIKELY TO BURN OFF BY MID MORNING. BY THIS TIME
THE LOW CLOUDS SHOULD BE WORKING THEIR WAY INTO NORTHERN MO. THE NET
EFFECT IS SUNSHINE COULD BE IN SHORT SUPPLY TODAY. MAX TEMPERATURES
REFLECT THIS IDEA.
LATEST SREF SURFACE VISIBILITY PROBABILITY PROG WHICH CORRECTLY
FORECAST THIS MORNINGS DENSE FOG IS SIGNALING THE POTENTIAL FOR
DENSE FOG FOR TONIGHT OVER THE NW 1/4 OF THE CWA. THIS WOULD FIT
WITH THE STRATUS/DRIZZLE NOW OVER CENTRAL OK ADVECTING NNE ACROSS KS
AND EVENTUALLY NW MO.
A COUPLE OF SHORTWAVES WILL PASS THROUGH THE PLAINS AND MID MO
VALLEY DURING THE SUNDAY-TUESDAY TIME FRAME. THE INITIAL SHORTWAVE
MOVING INTO THE CENTRAL HIGH PLAINS ON SUNDAY WILL MOST LIKELY
WEAKEN AS IT IS CAUGHT IN BETWEEN A STRONGER UPSTREAM SHORTWAVE
DIVING INTO THE ROCKIES AND THE UPPER WAVE NOW OVER EASTERN TX. THIS
INITIAL SHORTWAVE WILL LIKELY ONLY HAVE SOME MID/HIGH CLOUDS WITH IT
SO PRECIPITATION IS NOT LIKELY TO FALL IN OUR CWA.
THE SECOND SYSTEM LOOKS LIKE IT WILL BE A DIFFERENT ANIMAL AS IT
DIVES SOUTHEAST WITH A NEGATIVE TILT. NAM/GFS/ECMWF/SREF/GEM ALL
CLOSE OFF THE UPPER CIRCULATION MONDAY NIGHT. THERE IS DECENT MODEL
CONSISTENCY IN THE PLACEMENT OF THE UPPER LOW AND GENERAL DEPICTION
OF THE UPPER WAVE. EARLIER GFS RUNS WERE TOO PROGRESSIVE WITH THE
SURFACE COLD FRONT AND THE 06Z MODEL RUN IS NOW MORE IN LINE WITH
THE NAM/ECMWF. WITH INCREASING CONFIDENCE ON EVOLUTION OF THIS
SYSTEM HAVE INCREASED POPS FOR MONDAY NIGHT/TUESDAY. ANOTHER MODEL
RUN OR TWO SHOWING THIS SAME CONSISTENCY SHOULD ALLOW LATER SHIFTS
TO RAISE POPS TO LIKELY.
MJ
&&
.AVIATION...
MAIN AVIATION CONCERNS AGAIN FOCUSED ON THE NEXT SEVERAL HOURS.
REGIONAL FOG PLOT SATELLITE IMAGERY SHOWED DENSE FOG ACROSS NORTHERN
MISSOURI WITH A DECK OF MVFR/VFR STRATUS RAPIDLY MOVING NORTH INTO
THE KANSAS CITY METRO. WITH THIS DECK EXPECTED TO IMPACT THE METRO
SITES DURING A TIME WHEN PEAK FOG FORMATION WOULD TYPICALLY OCCUR THE
DENSE FOG POTENTIAL AT MCI LOOKS SMALL RIGHT NOW. DOWNSTREAM
OBSERVATIONS WITHIN THIS STRATUS HAVE VARIED FROM 2900 FT TO GREATER
THAN 3500 FT. SO WILL MENTION CIGS AROUND 3000 FT. BUT THESE COULD
REALLY VARY FROM MVFR TO VFR THROUGH THE EARLY MORNING BEFORE
EVENTUALLY BECOMING VFR LATER THIS MORNING. AT STJ DENSE FOG WILL
PERSIST THROUGH MUCH OF THE MORNING BEFORE BURNING OFF. ALL SITES ARE
EXPECTED TO BE VFR BY THIS AFTERNOON AND INTO THE EVENING HOURS.
THERE IS SOME POTENTIAL FOR FOG AND LOWER CIGS TONIGHT. SOUTHERLY
WINDS ARE EXPECTED TO ADVECT SLIGHTLY MORE MOIST AIR INTO THE
REGION. WINDS ARE NOT CURRENTLY EXPECTED TO DECOUPLE SO CONFIDENCE IS
STILL SOMEWHAT LOW ON JUST HOW DENSE FOG MAY BE.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR MOZ001>008-
011>017-020>024.
KS...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR KSZ025-102.
&&
$$
000
FXUS63 KSGF 211057
AFDSGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
457 AM CST SAT NOV 21 2009
...UPDATE TO AVIATION...
.DISCUSSION...
FORECAST CHALLENGES DEAL PRIMARILY WITH TEMPERATURES THROUGH THE
WEEKEND...FOLLOWED BY TIMING OF NEXT FROPA THE EARLY PART OF NEXT WEEK.
CURRENTLY...SURFACE HIGH CENTERED OVER ILLINOIS THIS MORNING
GIVING US AN EASTERLY TO SOUTHEASTERLY WIND FLOW. 11-3.9U SATELLITE
IMAGERY SHOWING STRATUS DECK STILL HANGING ACROSS SOUTHERN
MISSOURI INTO NORTHERN ARKANSAS. TEMPERATURES REMAIN QUITE WARM
WITH LOW 50S ACROSS SOUTHERN MISSOURI AND MID 40S ACROSS CENTRAL
MISSOURI AT THIS TIME. OUR NEXT STORM SYSTEM MOVING INTO THE
ROCKIES THIS MORNING WITH RIDGING FROM NEW MEXICO NORTH INTO NORTH
DAKOTA OUT AHEAD OF THIS SYSTEM. UPPER CIRCULATION CONTINUES OVER
NORTHERN TEXAS ON WATER VAPOR IMAGERY WITH DRY SLOTTING OVER MOST
OF THE CWA.
FOR THIS WEEKEND...GENERALLY FOLLOWED MET GUIDANCE ON TEMPERATURES
AS IT HAS BEEN DOING VERY WELL THE PAST COUPLE DAYS. SHOULD SEE
TEMPERATURES ONCE AGAIN IN THE LOW 60S AS THE STRATUS DECK BREAKS
UP...DESPITE 850/925MB TEMPERATURES BEING A LITTLE COOLER TODAY
OVER YESTERDAY. THIS COOLING SHOULD BE OFFSET BY SUNSHINE THIS
AFTERNOON. UPPER LOW OVER TEXAS FORECAST TO TRACK ACROSS NORTHERN
LOUISIANA THROUGH THE DAY...EFFECTIVELY CUTTING OFF ANY GULF
MOISTURE RETURN. LOOKS DRY AND WARM THROUGH THE WEEKEND BEFORE OUR
NEXT SYSTEM APPROACHES EARLY NEXT WEEK. CONTINUED FOLLOWING
MET/WRF GUIDANCE ON TEMPERATURES. GFS DOES SHOW A WEAK SHORTWAVE
PUSHING THROUGH THE AREA SUNDAY AFTERNOON...BUT WITH NO GULF
MOISTURE RETURN...KEPT THE FORECAST DRY.
THE 00Z GFS STARTING TO COME MORE IN LINE WITH THE ECMWF ON
POSITIONING OF UPPER LOW AND ASSOCIATED COLD FRONT MONDAY
AFTERNOON INTO TUESDAY. STILL A LITTLE FURTHER NORTH WITH THE LOW
CENTER TRACKING ACROSS IOWA..WHILE ECMWF TRACK IT MORE ACROSS
NORTH CENTRAL MISSOURI MONDAY NIGHT. BOTH SHOW A FAIRLY STRONG
COLD FRONT PUSHING THROUGH MONDAY NIGHT INTO TUESDAY AND HAVE
CONTINUED CHANCE POPS FOR THIS TIME FRAME. PRETTY GOOD SHOT OF COLD
AIR BEHIND THE FRONT AS WELL WITH 850MB TEMPERATURES FALLING TO
-4C TUESDAY AFTERNOON. A SECONDARY SHORTWAVE WITH ANOTHER SHOT OF
COLD AIR LOOKS TO BE ON TAP FOR WEDNESDAY WITH 850MB TEMPERATURES
FALLING TO -6C...SO LOOKS LIKE TUESDAY THROUGH THURSDAY WILL
PROBABLY SEE TEMPERATURES BELOW NORMAL BASED ON BETTER AGREEMENT
BETWEEN THE TWO MODELS. WILL MOST LIKELY SEE OUR FIRST REAL FREEZE
OF THE SEASON THURSDAY MORNING WITH LOWS IN THE UPPER 20S AREA WIDE.
CLAYCOMB
&&
.AVIATION...
FOR THE 12Z TAFS...JLN/BBG ON THE EDGE OF VFR/MVFR CATEGORY AND
BELIEVE MVFR MAY BE POSSIBLE BY 13-14Z THROUGH THE MORNING HOURS.
OTHERWISE EXPECTING VFR CEILINGS THROUGH THE PERIOD.
LINDENBERG
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KEAX 211022
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
422 AM CST SAT NOV 21 2009
.DISCUSSION...
DENSE FOG WILL BE THE SHORT TERM PROBLEM AS MUCH OF NORTHERN MO IS
EXPERIENCING VISIBILITIES A QUARTER OF A MILE OR LESS. CONDITIONS
WILL IMPROVE BY LATE MORNING AS THE FOG LIFTS TO FORM A STRATUS
DECK. SATELLITE IMAGERY ALSO SHOWS A LOW CLOUD DECK TIED TO DEEPER
MOISTURE ADVECTING NORTH FROM TX/OK/AR. A WEAK W-E SURFACE RIDGE
CUTTING THROUGH THE CENTER OF THE CWA DIVIDES DENSE FOG TO THE NORTH
AND THE LOW CLOUDS TO THE SOUTH. THIS RIDGE AXIS IS EXPECTED TO
FALL APART TO DAY AS SURFACE TROUGHING OVER THE HIGH PLAINS PUSHES
EAST AND DISPLACES THE RIDGE...THUS ALLOWING THE LOW CLOUDS TO
SPREAD INTO NORTHERN MO. SPECIAL FOG LOOP SUGGESTS THE DENSE FOG IS
RATHER SHALLOW AND LIKELY TO BURN OFF BY MID MORNING. BY THIS TIME
THE LOW CLOUDS SHOULD BE WORKING THEIR WAY INTO NORTHERN MO. THE NET
EFFECT IS SUNSHINE COULD BE IN SHORT SUPPLY TODAY. MAX TEMPERATURES
REFLECT THIS IDEA.
LATEST SREF SURFACE VISIBILITY PROBABILITY PROG WHICH CORRECTLY
FORECAST THIS MORNINGS DENSE FOG IS SIGNALING THE POTENTIAL FOR
DENSE FOG FOR TONIGHT OVER THE NW 1/4 OF THE CWA. THIS WOULD FIT
WITH THE STRATUS/DRIZZLE NOW OVER CENTRAL OK ADVECTING NNE ACROSS KS
AND EVENTUALLY NW MO.
A COUPLE OF SHORTWAVES WILL PASS THROUGH THE PLAINS AND MID MO
VALLEY DURING THE SUNDAY-TUESDAY TIME FRAME. THE INITIAL SHORTWAVE
MOVING INTO THE CENTRAL HIGH PLAINS ON SUNDAY WILL MOST LIKELY
WEAKEN AS IT IS CAUGHT IN BETWEEN A STRONGER UPSTREAM SHORTWAVE
DIVING INTO THE ROCKIES AND THE UPPER WAVE NOW OVER EASTERN TX. THIS
INITIAL SHORTWAVE WILL LIKELY ONLY HAVE SOME MID/HIGH CLOUDS WITH IT
SO PRECIPITATION IS NOT LIKELY TO FALL IN OUR CWA.
THE SECOND SYSTEM LOOKS LIKE IT WILL BE A DIFFERENT ANIMAL AS IT
DIVES SOUTHEAST WITH A NEGATIVE TILT. NAM/GFS/ECMWF/SREF/GEM ALL
CLOSE OFF THE UPPER CIRCULATION MONDAY NIGHT. THERE IS DECENT MODEL
CONSISTENCY IN THE PLACEMENT OF THE UPPER LOW AND GENERAL DEPICTION
OF THE UPPER WAVE. EARLIER GFS RUNS WERE TOO PROGRESSIVE WITH THE
SURFACE COLD FRONT AND THE 06Z MODEL RUN IS NOW MORE IN LINE WITH
THE NAM/ECMWF. WITH INCREASING CONFIDENCE ON EVOLUTION OF THIS
SYSTEM HAVE INCREASED POPS FOR MONDAY NIGHT/TUESDAY. ANOTHER MODEL
RUN OR TWO SHOWING THIS SAME CONSISTENCY SHOULD ALLOW LATER SHIFTS
TO RAISE POPS TO LIKELY.
MJ
&&
.AVIATION...
FOR THE 06Z TAFS...OVERALL...THERE WERE ONLY MINOR CHANGES MADE TO
THE PREVIOUS FORECASTS. CONCERN FOR OVERNIGHT DENSE FOG REMAINS IN
PLAY FOR KSTJ AND TO A LESSER DEGREE KMCI. TERMINAL CURRENTLY
REPORTS LIFR CONDITIONS AND VLIFR IS CERTAINLY POSSIBLE AFTER 11Z. A
SURFACE RIDGE AXIS FROM EAST CENTRAL KS THROUGH KMCI TO SOUTH OF
KIRK WILL BE THE DEMARCATION LINE BETWEEN DENSE FOG NORTH OF THIS
AXIS AND MVFR STRATUS/FOG TO THE SOUTH. THIS SURFACE RIDGE AXIS IS
EXPECTED TO MOVE LITTLE OVERNIGHT SO KMCI WILL BE ON THE BORDERLINE
AND HENCE COULD GO EITHER WAY WITH YEA/NAY ON DENSE FOG. WILL LIKELY
BE NEEDING A FEW AMENDMENTS FOR KMCI.
THE DENSE FOG SHOULD BE SLOW TO DISSIPATE SATURDAY MORNING AND COULD
LAST FOR THE ENTIRE MORNING. ONCE THE FOG LIFTS/DISSIPATES AM STILL
EXPECTING TO SEE CONSIDERABLE MVFR CEILINGS FOR THE REST OF THE DAY
AS LOW LEVEL WARM AIR ADVECTION/ISENTROPIC LIFT PULLS UP THE
EXTENSIVE LOW CLOUD FIELD NOW COVERING OK/SOUTH CENTRAL KS/SOUTHERN
MO.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KLSX 210925
AFDLSX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
325 AM CST SAT NOV 21 2009
.DISCUSSION...
/320 AM CST SAT NOV 21 2009/
MAIN CONCERNS DEAL WITH EXTENT OF FOG THIS MORNING AND CHANCES OF
RAIN EARLY NEXT WEEK.
SOLID BAND OF CLOUDS OVER THE CWA LAST EVENING HAS BROKEN UP THE
PAST FEW HOURS. THIS COMBINED WITH THE LIGHT WINDS CAUSED BY OUR
CLOSE PROXIMITY TO CENTER OF SFC HIGH PRESSURE OVER NRN INDIANA
HAS CAUSED AREAS OF FOG. FEWER OB SITES ARE REPORTING DENSE
FOG...PRIMARILY IN LOW LYING AREAS LIKE CPS/SUS...THAN YESTERDAY
MORNING. WILL INCLUDE AREAS OF FOG IN THE FORECAST AND THE PATCHY
DENSE FOG IN NOWCASTS. LIKE YESTERDAY...FOG SHOULD DISSIPATE BY
MID MORNING. TIME CROSS SECTIONS ARE SHOWING HIGH RH VALUES
THROUGH TONIGHT BETWEEN 5-8KFT AND A LARGE AREA OF CLOUDS OVER
CURRENTLY OVER WRN AND SRN MO IS MOVING NEWD INTO THE CWA. HAVE
MOSTLY CLOUDY GOING OVER MOST OF THE CWA TODAY WITH CLEARING
TONIGHT. DRY WEATHER WILL DOMINATE THROUGH TOMORROW AS AREA LIES
UNDER NEUTRAL VERTICAL MOTION OR SUBSIDENCE BENEATH BUILDING UPPER
RIDGE.
AGREEMENT IN MODELS BEGINS TO DIVERGE BY EARLY NEXT WEEK WHEN THE
NAM SLIGHTLY TRAILS THE OTHER MODELS WITH A WEAK SHORTWAVE TROUGH
THAT CROSSES MO/IL ON SUNDAY NIGHT. THERE WILL NOT BE ENOUGH LARGE
SCALE ASCENT OR MOISTURE WITH THIS SYSTEM TO INCLUDE A CHANCE OF
RAIN AT THIS TIME. THERE IS ALSO SOME DISPARITY WITH THE TIMING OF
A MUCH STRONGER CLOSED LOW AND ACCOMPANYING COLD FRONT WITH THE
NAM SHOWING A FROPA ABOUT 6-12 HOURS LATER ON TUESDAY THAN THE
GFS. THE CANADIAN GEM SUPPORTS THE FASTER GFS AND THE ECMWF FAVORS
THE NAM SO USED A COMBINATION OF ALL OF THEM...USING A BLEND OF
THE SREF MEAN AND THE GFS MOS FOR THE MASS FIELDS. THIS CALLS FOR
GOING DRY THROUGH MONDAY WITH A CHANCE POPS WITH FROPA MONDAY
NIGHT AND TUESDAY.
WENT CLOSER TO THE COOLER GFS MOS FOR TEMPS TODAY GIVEN EXPECTED
MOSTLY CLOUDY SKIES AND LIGHT SELY WINDS. WENT TOWARD THE WARMER
SIDE OF GUIDANCE SUNDAY MONDAY AS I EXPECT MORE SUN AND WINDS
VEERING SLY AHEAD STORM SYSTEM EARLY NEXT WEEK.
BRITT
&&
.AVIATION...
/1055 PM CST FRI NOV 20 2009/
FOR THE 06Z TAFS...HIGH SC/LOW AC HAS SPREAD OVER REGION...
ESPECIALLY OVER TAF SITES THIS EVENING. THIS HAS BASICALLY STALLED
ANY FOG FORMATION. SO BACKED OFF ON HOW MUCH FOG WILL DEVELOP. HAVE
SOME MVFR FOG AT KCOU AND KSTL AFTER 10Z...WHILE KSUS AND KUIN COULD
SEE ENOUGH BREAKS IN THE CLOUDS FOR MVFR/IFR FOG TO FORM...WITH
TEMPOS OF VSBYS DOWN TO 2 MILES AT TIMES. DO NOT EXPECT ANY MVFR/IFR
CIGS TONIGHT...JUST VFR CIGS WHICH WILL LINGER THROUGH MOST OF THE
DAY TODAY...BEFORE SCATTERING OUT THIS AFTERNOON AND EVENING...WITH
LIGHT AND VARIABLE WINDS PICKING UP FROM THE SOUTHEAST DURING THIS
TIME.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KSGF 210723
AFDSGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
123 AM CST SAT NOV 21 2009
.DISCUSSION...
FORECAST CHALLENGES DEAL PRIMARILY WITH TEMPERATURES THROUGH THE
WEEKEND...FOLLOWED BY TIMING OF NEXT FROPA THE EARLY PART OF NEXT WEEK.
CURRENTLY...SURFACE HIGH CENTERED OVER ILLINOIS THIS MORNING
GIVING US AN EASTERLY TO SOUTHEASTERLY WIND FLOW. 11-3.9U SATELLITE
IMAGERY SHOWING STRATUS DECK STILL HANGING ACROSS SOUTHERN
MISSOURI INTO NORTHERN ARKANSAS. TEMPERATURES REMAIN QUITE WARM
WITH LOW 50S ACROSS SOUTHERN MISSOURI AND MID 40S ACROSS CENTRAL
MISSOURI AT THIS TIME. OUR NEXT STORM SYSTEM MOVING INTO THE
ROCKIES THIS MORNING WITH RIDGING FROM NEW MEXICO NORTH INTO NORTH
DAKOTA OUT AHEAD OF THIS SYSTEM. UPPER CIRCULATION CONTINUES OVER
NORTHERN TEXAS ON WATER VAPOR IMAGERY WITH DRY SLOTTING OVER MOST
OF THE CWA.
FOR THIS WEEKEND...GENERALLY FOLLOWED MET GUIDANCE ON TEMPERATURES
AS IT HAS BEEN DOING VERY WELL THE PAST COUPLE DAYS. SHOULD SEE
TEMPERATURES ONCE AGAIN IN THE LOW 60S AS THE STRATUS DECK BREAKS
UP...DESPITE 850/925MB TEMPERATURES BEING A LITTLE COOLER TODAY
OVER YESTERDAY. THIS COOLING SHOULD BE OFFSET BY SUNSHINE THIS
AFTERNOON. UPPER LOW OVER TEXAS FORECAST TO TRACK ACROSS NORTHERN
LOUISIANA THROUGH THE DAY...EFFECTIVELY CUTTING OFF ANY GULF
MOISTURE RETURN. LOOKS DRY AND WARM THROUGH THE WEEKEND BEFORE OUR
NEXT SYSTEM APPROACHES EARLY NEXT WEEK. CONTINUED FOLLOWING
MET/WRF GUIDANCE ON TEMPERATURES. GFS DOES SHOW A WEAK SHORTWAVE
PUSHING THROUGH THE AREA SUNDAY AFTERNOON...BUT WITH NO GULF
MOISTURE RETURN...KEPT THE FORECAST DRY.
THE 00Z GFS STARTING TO COME MORE IN LINE WITH THE ECMWF ON
POSITIONING OF UPPER LOW AND ASSOCIATED COLD FRONT MONDAY
AFTERNOON INTO TUESDAY. STILL A LITTLE FURTHER NORTH WITH THE LOW
CENTER TRACKING ACROSS IOWA..WHILE ECMWF TRACK IT MORE ACROSS
NORTH CENTRAL MISSOURI MONDAY NIGHT. BOTH SHOW A FAIRLY STRONG
COLD FRONT PUSHING THROUGH MONDAY NIGHT INTO TUESDAY AND HAVE
CONTINUED CHANCE POPS FOR THIS TIME FRAME. PRETTY GOOD SHOT OF COLD
AIR BEHIND THE FRONT AS WELL WITH 850MB TEMPERATURES FALLING TO
-4C TUESDAY AFTERNOON. A SECONDARY SHORTWAVE WITH ANOTHER SHOT OF
COLD AIR LOOKS TO BE ON TAP FOR WEDNESDAY WITH 850MB TEMPERATURES
FALLING TO -6C...SO LOOKS LIKE TUESDAY THROUGH THURSDAY WILL
PROBABLY SEE TEMPERATURES BELOW NORMAL BASED ON BETTER AGREEMENT
BETWEEN THE TWO MODELS. WILL MOST LIKELY SEE OUR FIRST REAL FREEZE
OF THE SEASON THURSDAY MORNING WITH LOWS IN THE UPPER 20S AREA WIDE.
CLAYCOMB
&&
.AVIATION...
FOR THE 21/0600Z KSGF/KJLN/KBBG TAFS...CLOUD COVER/VFR CEILINGS
CONTINUE OVER THE TAF SITES...WITH SOME LOWER MVFR CEILINGS
LURKING HERE AND THERE AS WELL. PROGGED (AND OBSERVED 00Z) SOUNDINGS
STILL SHOWING A FAIR AMOUNT CLOUDS/MOISTURE IN THE LOWEST 2KM AS
WELL...BUT SATELLITE TRENDS HAVE SHOWN THINNING OR CLEARING IN
SPOTS...AND WHERE CLEARING CAN OCCUR...WE SHOULD SEE MORE OF A
REDUCTION IN VISIBILITY WITH RADIATION FOG. ALL IN ALL...TRENDS
WILL NEED TO BE WATCHED...BUT WENT WITH MORE OF CLOUDY (MAINLY
MVFR CEILING CATEGORY) SCENARIO WITH A BRIEF CHANCE OF SOME IFR
VISIBILITY NEAR SUNRISE /11Z-14Z.
DSA
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KEAX 210557
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1157 PM CST FRI NOV 20 2009
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
MAIN CONCERN THROUGH THE SHORT TERM WILL BE WITH FOG POTENTIAL
TONIGHT INTO TOMORROW MORNING. WEAK SFC RIDGE REMAINS STATIONED
ACROSS THE CWA THIS AFTERNOON AND WILL LIKELY REMAIN IN PLACE THROUGH
THIS EVENING. THIS WILL LIKELY LEAD TO CONTINUED LIGHT AND VARIABLE
SFC WINDS THROUGH AT LEAST THE EARLY PART OF TONIGHT. BROAD TROUGH
WILL ENGULF THE WESTERN CONUS TONIGHT LEADING TO PRESSURE FALLS ALONG
THE LEE OF THE ROCKIES. THIS WILL BRING ABOUT A MORE SOUTHERLY LLVL
FLOW REGIME BY LATE TONIGHT INTO THE MORNING HOURS. COMPLICATED
FORECAST DEALING WITH THE POSSIBILITY OF DENSE FOG OVERNIGHT AS A
COMBINATION OF RADIATIONAL AND ADVECTION PROCESSES WILL LIKELY BE AT
WORK. CLOUD COVER ACROSS THE SOUTHERN COUNTIES HAS ALL BUT DISSIPATED
ATTM WITH THE BULK OF THE REMAINING ACTIVITY CONFINED TO THE SOUTHERN
PLAINS AND OZARKS. BELIEVE THE MAJORITY OF THE CWA WILL REMAIN FAIRLY
CLEAR THROUGH THIS EVENING AND EARLY NIGHTTIME HOURS ALLOWING FOR
EFFICIENT RADIATIONAL COOLING TO COMMENCE. THIS WILL ALLOW THE
BOUNDARY LAYER TO COME CLOSE TO SATURATION AND PERHAPS RESULT IN
AREAS OF FOG FORMATION BY MIDNIGHT. HOWEVER LATER TONIGHT...A WEAK
WARM FRONT WILL LIFT NORTHWARD INTO THE SOUTHERN CWA ALLOWING LLVL
MOISTURE AND CLOUD COVER TO MAKE A DECENT SURGE NORTHWARD. THIS
SHOULD BRING ABOUT ADDITIONAL FOG DEVELOPMENT ACROSS THESE AREAS
TOWARDS THE EARLY MORNING HOURS. HOWEVER AS THIS OCCURS...SFC FLOW
WILL LIKELY INCREASE A BIT AS THE SFC RIDGE BECOMES BETTER
ESTABLISHED ACROSS THE OHIO VALLEY AND PRESSURE CONTINUE TO FALL
ACROSS THE HIGH PLAINS. THEREFORE...UNCERTAINTY EXISTS AS TO THE
EXTENT AND DENSITY OF FOG WHERE RADIATIONAL PROCESSES DOMINATE. WILL
INCLUDE AREAS OF FOG ACROSS THE ENTIRE CWA OVERNIGHT AND LEAVE IT TO
LATER SHIFTS TO HOIST ANY ADVISORIES AS MORE CONFIDENCE IN
LOCATION...TIMING...AND DENSITY IS GAINED. FOG WILL LIKELY LINGER
THROUGH THE MID MORNING HOURS BEFORE GRADUALLY BURNING OFF.
BY TOMORROW...LEE SIDE TROUGHING WILL LEAD TO INCREASED SOUTHERLY
LLVL FLOW AND SLIGHTLY WARMER TEMPS ACROSS MOST AREAS. SFC FRONT WILL
SLIDE INTO EASTERN NEBRASKA/CENTRAL KANSAS BY SATURDAY NIGHT INTO
SUNDAY MORNING BEFORE STALLING AS NEXT SHORT WAVE TROUGH DIVES INTO
THE ROCKIES AND FURTHER PRESSURE FALLS TAKE SHAPE ACROSS THE HIGH
PLAINS. THIS WAVE WILL THEN PUSH INTO THE PLAINS ON SUNDAY LIKELY
BRINGING THE WEAK SFC BOUNDARY CLOSER TO THE CWA AND BRING AT LEAST A
SLIGHT CHC OF SHOWERS TO THE NORTHWESTERN COUNTIES DURING THE DAY.
DEROCHE
MEDIUM RANGE (MONDAY THROUGH FRIDAY)...
FOR NEXT WORK WEEK THE PRIMARY WEATHER ISSUE WILL BE THE DEVELOPMENT
OF A PROGRESSIVE TROUGH THAT WILL POSSIBLY BRING SOME PRECIPITATION
TO THE CENTRAL PLAINS. MID RANGE MODELS ARE CURRENTLY ADVERTISING A
SERIES OF SHORTWAVES TO MOVE THROUGH THE PLAINS OVER THE WEEKEND AND
NEXT WEEK WITH A MODESTLY LARGE TROUGH DEVELOPING IN RESPONSE ACROSS
THE CENTRAL PLAINS MONDAY/TUESDAY. MODELS HAVE BE CONSISTENT IN
ADVERTISING ITS DEVELOPMENT...BUT THE TIMING IS A BIT OF AN ISSUE.
LATEST RUN OF THE THE GFS CONTINUES TO BE THE OUTLIER AS IT IS THE
FASTEST SOLUTION. GEM/ECMWF/UKMET ALL HAVE THE SYSTEM MOVING MORE
SLOWLY THROUGH THE PLAINS...WHICH SEEMS REASONABLE DUE TO THE
STRENGTH OF THE JET ROUNDING ITS BASE.
SO...WHILE TIMING PREFERENCE IS HEDGED TOWARDS THE ECMWF/UKMET/GEM
COMBINATION...THE TRACK OF THE TROUGH ACROSS THE PLAINS IS FAIRLY
CHAOTIC. THE GFS IS ADVERTISING THE INITIAL TROUGH DIGGING STRAIGHT
THROUGH THE NORTHERN PLAINS INTO MISSOURI...WITH A SECONDARY WAVE
DIGGING INTO ITS BACK SIDE AND RELOADING THE TROUGH FOR THURSDAY.
THE GEM AND ECMWF KEEP THE FEATURE MORE AS ONE COHERENT SHORT LIVED
CUTOFF LOW AS IT MOVES INTO AND THEN BACK OUT OFF THE PLAINS. HAVE
OPTED NOT TO ADJUST THE FORECAST TOO MUCH DUE TO THE VERITY AND THE
LACK OF CONFIDENCE IN THE CURRENT SET OF SOLUTIONS. CHANCE POPS FOR
PORTIONS OF THE FORECAST AREA MONDAY THROUGH TUESDAY SEEMS TO STILL
BE A GOOD IDEA...THOUGH DETAILS ARE STILL A BIT VAGUE. GENERAL TREND
WOULD AT LEAST INDICATE THAT...GIVEN THE SOURCE REGION OF OF THE AIR
MASS BEHIND THE TROUGH...IT SHOULD BE TOO WARM FOR ANY FROZEN
PRECIPITATION. SO...FOR NOW HAVE SIMPLY KEPT OUR GOING PRECIPITATION
AS RAIN. OTHERWISE...REMAINDER OF THE WORK WEEK CURRENTLY LOOKS DRY
AS SOME FORM OF RIDGING WILL BEGIN TO BUILD IN FROM THE WEST...
PUSHING THE NORTHWEST FLOW BEHIND THE TROUGH OFF TO THE EAST.
CUTTER
&&
.AVIATION...
FOR THE 06Z TAFS...OVERALL...THERE WERE ONLY MINOR CHANGES MADE TO
THE PREVIOUS FORECASTS. CONCERN FOR OVERNIGHT DENSE FOG REMAINS IN
PLAY FOR KSTJ AND TO A LESSER DEGREE KMCI. TERMINAL CURRENTLY
REPORTS LIFR CONDITIONS AND VLIFR IS CERTAINLY POSSIBLE AFTER 11Z. A
SURFACE RIDGE AXIS FROM EAST CENTRAL KS THROUGH KMCI TO SOUTH OF
KIRK WILL BE THE DEMARCATION LINE BETWEEN DENSE FOG NORTH OF THIS
AXIS AND MVFR STRATUS/FOG TO THE SOUTH. THIS SURFACE RIDGE AXIS IS
EXPECTED TO MOVE LITTLE OVERNIGHT SO KMCI WILL BE ON THE BORDERLINE
AND HENCE COULD GO EITHER WAY WITH YEA/NAY ON DENSE FOG. WILL LIKELY
BE NEEDING A FEW AMENDMENTS FOR KMCI.
THE DENSE FOG SHOULD BE SLOW TO DISSIPATE SATURDAY MORNING AND COULD
LAST FOR THE ENTIRE MORNING. ONCE THE FOG LIFTS/DISSIPATES AM STILL
EXPECTING TO SEE CONSIDERABLE MVFR CEILINGS FOR THE REST OF THE DAY
AS LOW LEVEL WARM AIR ADVECTION/ISENTROPIC LIFT PULLS UP THE
EXTENSIVE LOW CLOUD FIELD NOW COVERING OK/SOUTH CENTRAL KS/SOUTHERN
MO.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KSGF 210547
AFDSGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1147 PM CST FRI NOV 20 2009
...UPDATE TO AVIATION...
.DISCUSSION...
IT WAS A MILD AND RELATIVELY QUIET DAY OVER EXTREME SOUTHEAST KANSAS
AND THE MISSOURI OZARKS. TEMPERATURES WERE GENERALLY IN THE UPPER
50S AND LOWER 60S...UNDER MOSTLY CLOUDY SKIES AND LIGHT WINDS. AN
INVERTED SURFACE TROUGH WAS POSITIONED ACROSS FAR SOUTHWEST
MISSOURI...WHICH BECAME A FOCUS FOR SOME SPRINKLES AND LIGHT RAIN
SHOWERS. THESE SHOWERS WERE CONFINED TO MCDONALD...NEWTON...AND
BARRY COUNTIES. ALL OTHER LOCATIONS REMAINED DRY.
THIS SURFACE TROUGH WILL REMAIN POSITIONED OVER THE REGION
TONIGHT...CAUSING THE LOWER TROP TO BECOME VERY SATURATED BY EARLY
SATURDAY MORNING. POINT FORECAST SOUNDINGS OVER THE WESTERN HALF OF
THE CWA SUGGESTS THE POTENTIAL FOR SOME STRATUS BUILD DOWN. I WILL
ADD AREAS OF DENSE FOG TO THIS AREA FROM 9Z - 15Z. DUE TO EXISTING
CLOUD COVER...I OPTED NOT TO ISSUE A DENSE FOG ADVISORY JUST
YET...AND WILL ALLOW THE EVENING SHIFT TO MONITOR AND PINPOINT WHICH
COUNTIES MAY NEED ONE. WEAK SURFACE WINDS WILL ALSO BE A CONDUCIVE
INGREDIENT FOR DENSE FOG.
LIGHT RAIN CHANCES WILL ALSO ACCOMPANY THE INVERTED SURFACE TROUGH.
AGAIN...MOST AREAS TONIGHT WILL REMAIN DRY...HOWEVER...LOCATIONS
ACROSS FAR SOUTHERN MISSOURI WILL EXPERIENCE THESE SPRINKLES AND
LIGHT RAIN. WILL CONTINUE WITH LIGHT RAIN CHANCES FOR AREAS SOUTH
OF HIGHWAY 60...AND EAST OF HIGHWAY 71...WHICH ENCOMPASSES FAR
SOUTHERN MISSOURI.
AN UPPER LEVEL DISTURBANCE WAS TRANSLATING ACROSS THE INTERSTATE 20
CORRIDOR OF TEXAS THIS AFTERNOON. THIS FEATURE WILL SHIFT TO THE
EAST NORTHEAST SATURDAY AND SATURDAY NIGHT...CAUSING A SHIELD OF
LIGHT RAIN TO DEVELOP OVER ARKANSAS...SOUTHEAST MISSOURI...AND
WESTERN KENTUCKY. THERE IS A SLIGHT CHANCE THAT AREAS OF HOWELL OR
OREGON COUNTY MAY BE CLIPPED BY THIS SHIELD OF RAIN LATE SATURDAY
NIGHT OR SUNDAY MORNING. IF RAIN DOES OCCUR IN THESE AREAS...THEN
ONLY LIGHT AMOUNTS ARE EXPECTED. THE REST OF THE REGION WILL REMAIN
DRY AND MILD...WITH HIGHS SATURDAY AND SUNDAY REACHING THE LOWER
60S. A MIX OF SUN AND CLOUDS CAN BE EXPECTED THROUGH MUCH OF THE
WEEKEND.
ZONAL FLOW WILL GIVE WAY TO A DEEPENING UPPER LEVEL LOW PRESSURE
SYSTEM MONDAY NIGHT INTO EARLY TUESDAY MORNING. THIS FEATURE WILL
ALSO FORCE A COLD FRONT INTO THE REGION...WHICH WILL CAUSE A DECENT
COOL DOWN FOR THE MIDDLE OF NEXT WEEK. AS A MATTER OF FACT...THE
UPPER PATTERN BECOMES EVEN MORE AMPLIFIED THROUGH LATE NEXT WEEK AS
A STRONG RIDGE OVER THE MOUNTAIN WEST...CAUSES A PIPELINE OF
CANADIAN AIR TO PLUNGE SOUTHWARD INTO THE NATIONS MID SECTION.
SEVERAL SHORTWAVE TROUGHS WILL MIGRATE THROUGH THIS WAVE
INFLECTION...REINFORCING A CLOUDY AND COOL WEATHER REGIME FOR THE
OZARKS. DESPITE THIS COLD AND DREARY PATTERN...THERE ARE NO
INDICATIONS FROM MODEL OUTPUT THAT WOULD SUGGEST FROZEN
PRECIPITATION THROUGH THE NEXT 7 DAYS.
CRAMER
&&
.AVIATION...
FOR THE 21/0600Z KSGF/KJLN/KBBG TAFS...CLOUD COVER/VFR CEILINGS
CONTINUE OVER THE TAF SITES...WITH SOME LOWER MVFR CEILINGS
LURKING HERE AND THERE AS WELL. PROGGED (AND OBSERVED 00Z) SOUNDINGS
STILL SHOWING A FAIR AMOUNT CLOUDS/MOISTURE IN THE LOWEST 2KM AS
WELL...BUT SATELLITE TRENDS HAVE SHOWN THINNING OR CLEARING IN
SPOTS...AND WHERE CLEARING CAN OCCUR...WE SHOULD SEE MORE OF A
REDUCTION IN VISIBILITY WITH RADIATION FOG. ALL IN ALL...TRENDS
WILL NEED TO BE WATCHED...BUT WENT WITH MORE OF CLOUDY (MAINLY
MVFR CEILING CATEGORY) SCENARIO WITH A BRIEF CHANCE OF SOME IFR
VISIBILITY NEAR SUNRISE /11Z-14Z. DSA
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KLSX 210455
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1055 PM CST FRI NOV 20 2009
.UPDATE...
/807 PM CST FRI NOV 20 2009/
OVERNIGHT ADJUSTMENTS HAVE BEEN MADE TO THE FORECAST IN LIGHT OF
THE RAPID DEVELOPMENT OF HIGH SC/LOW AC CLOUDS THAT HAVE DEVELOPED
PRIMARILY OVER THE I-70 CORRIDOR IN THE PAST FEW HOURS. THIS IS A
RESPONSE TO NARROW BUT INTENSE ISENTROPIC UPGLIDE MOST NOTICEABLE
AT THE 290K LEVEL. MODELS TAKE THIS LIFT AND MAINTAIN IT THRU THE
NIGHT AROUND THE I-70 CORRIDOR AND EVENTUALLY EXPAND IT INTO NERN
MO/WCNTRL IL. THESE CLOUDS SHOULD EFFECTIVELY KILL WIDESPREAD FOG
FORMATION FOR THE I-70 CORRIDOR...BUT FOR AREAS THAT CAN COOL
RAPIDLY ENOUGH IN THE FAR NRN FA AROUND QUINCY BEFORE THE CLOUDS
ROLL IN...AREAS OF FOG STILL EXPECTED TO FORM ALTHOUGH VSBYS WILL
LIKELY IMPROVE NEAR SUNRISE WHEN VSBYS ARE NORMALLY AT THEIR
WORST. SERN MO WILL BE JUST S OF THE BETTER ISENTROPIC UPGLIDE AND
SO WILL HAVE ENOUGH HOLES IN THE CLOUDS TO ALSO COOL OFF AND SO
HAVE ADDED AREAS OF FOG GIVEN THEIR RELATIVELY HIGH CROSSOVER
TEMPS IN THE MID 40S. MIN TEMP ADJUSTMENTS HAVE BEEN MADE TO
INCREASE BY SEVERAL DEGS FOR THE I-70 CORRIDOR BUT MAINTAINED THE
COOL PREVIOUS FORECAST FOR OTHER AREAS.
TES
&&
.DISCUSSION...
/319 PM CST FRI NOV 20 2009/
CLOUDS CONTINUE TO STREAM N-NEWD INTO MAINLY THE SRN HALF OF MO
AHEAD OF THE MID-UPPER LEVEL TROF OVER TX. LIGHT RAIN MOVING NEWD
INTO SWRN MO BUT IT APPEARS THAT MOST OF THIS RAIN WILL REMAIN S
OF THE CWA. SHOULD BE INCREASING CLOUD COVER THOUGH TGT INTO SAT
AS MODELS BRING LOW LEVEL MOISTURE CENTERED AROUND 850 MB IN
HEIGHT NWD. DESPITE INCREASING CLOUD COVER AND PLENTY OF DAYTIME
HEATING AND MIXING TDA ACROSS MOST OF THE CWA THERE SHOULD STILL
BE AT LEAST PATCHY FOG DEVELOPING LATE TGT. THE FOG SHOULD NOT BE
AS WIDESPREAD OR AS DENSE AS LAST NGT. LOW TEMPERATURES SHOULD
ALSO NOT BE QUITE AS COLD AS WELL. RAIN SHOULD REMAIN S OF THE CWA
THIS WEEKEND AS THE SRN MID-UPPER LEVEL TROF MOVES EWD THRU THE
GULF COAST REGION. THERE WILL ALSO BE A WEAKER MID-UPPER LEVEL TROF
WHICH WILL MOVE EWD THRU THE GREAT LAKES AND OHIO VALLEY REGIONS.
MAIN SFC RIDGE WILL BE CENTERED E OF THE CWA WITH MAINLY SELY SFC
WINDS THIS WEEKEND. HIGH TEMPERATURES WILL BE SIMILAR TO TODAY AND
ABOVE SEASONAL NORMALS. NAM MODEL GENERATES QPF OVER THE SERN HALF
OF THE CWA SUN NGT AHEAD OF A WEAK SHRTWV MOVING EWD THRU THE REGION
AND N OF A WEAK SFC LOW MOVING NWD THRU ERN AR. DISCOUNTED THIS AS
NO OTHER MODEL FITS THIS SOLUTION NOR DOES THE PREVIOUS NAM MODEL
RUNS GENERATE THIS RAIN SUN NGT. NEXT CHANCE OF RAIN SHOULD OCCUR
MON NGT AND TUE AS A STRONG MID-UPPER LEVEL TROF/LOW AND ASSOCIATED
CDFNT/SFC LOW MOVE EWD THRU THE REGION. STILL A LOT OF MODEL
UNCERTAINTY WITH THE POSITION OF THE UPPER LEVEL AND ASSOCIATED SFC
LOW AND HOW PROGRESSIVE THIS SYSTEM WILL BE. THE GFS MODEL CONTINUES
TO BE MORE PROGRESSIVE AND FURTHER N WITH THIS SYSTEM WHILE THE
ECMWF IS SLOWER AND FURTHER S. FOR NOW JUST INCLUDED CHANCE POPS FOR
MON NGT AND TUE...WITH COLDER TEMPERATURES FOR WED AND THU.
GKS
&&
.AVIATION...
/1055 PM CST FRI NOV 20 2009/
FOR THE 06Z TAFS...HIGH SC/LOW AC HAS SPREAD OVER REGION...
ESPECIALLY OVER TAF SITES THIS EVENING. THIS HAS BASICALLY STALLED
ANY FOG FORMATION. SO BACKED OFF ON HOW MUCH FOG WILL DEVELOP. HAVE
SOME MVFR FOG AT KCOU AND KSTL AFTER 10Z...WHILE KSUS AND KUIN COULD
SEE ENOUGH BREAKS IN THE CLOUDS FOR MVFR/IFR FOG TO FORM...WITH
TEMPOS OF VSBYS DOWN TO 2 MILES AT TIMES. DO NOT EXPECT ANY MVFR/IFR
CIGS TONIGHT...JUST VFR CIGS WHICH WILL LINGER THROUGH MOST OF THE
DAY TODAY...BEFORE SCATTERING OUT THIS AFTERNOON AND EVENING...WITH
LIGHT AND VARIABLE WINDS PICKING UP FROM THE SOUTHEAST DURING THIS
TIME.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 210207
AFDLSX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
807 PM CST FRI NOV 20 2009
.UPDATE...
/807 PM CST FRI NOV 20 2009/
OVERNIGHT ADJUSTMENTS HAVE BEEN MADE TO THE FORECAST IN LIGHT OF
THE RAPID DEVELOPMENT OF HIGH SC/LOW AC CLOUDS THAT HAVE DEVELOPED
PRIMARILY OVER THE I-70 CORRIDOR IN THE PAST FEW HOURS. THIS IS A
RESPONSE TO NARROW BUT INTENSE ISENTROPIC UPGLIDE MOST NOTICEABLE
AT THE 290K LEVEL. MODELS TAKE THIS LIFT AND MAINTAIN IT THRU THE
NIGHT AROUND THE I-70 CORRIDOR AND EVENTUALLY EXPAND IT INTO NERN
MO/WCNTRL IL. THESE CLOUDS SHOULD EFFECTIVELY KILL WIDESPREAD FOG
FORMATION FOR THE I-70 CORRIDOR...BUT FOR AREAS THAT CAN COOL
RAPIDLY ENOUGH IN THE FAR NRN FA AROUND QUINCY BEFORE THE CLOUDS
ROLL IN...AREAS OF FOG STILL EXPECTED TO FORM ALTHOUGH VSBYS WILL
LIKELY IMPROVE NEAR SUNRISE WHEN VSBYS ARE NORMALLY AT THEIR
WORST. SERN MO WILL BE JUST S OF THE BETTER ISENTROPIC UPGLIDE AND
SO WILL HAVE ENOUGH HOLES IN THE CLOUDS TO ALSO COOL OFF AND SO
HAVE ADDED AREAS OF FOG GIVEN THEIR RELATIVELY HIGH CROSSOVER
TEMPS IN THE MID 40S. MIN TEMP ADJUSTMENTS HAVE BEEN MADE TO
INCREASE BY SEVERAL DEGS FOR THE I-70 CORRIDOR BUT MAINTAINED THE
COOL PREVIOUS FORECAST FOR OTHER AREAS.
TES
&&
.DISCUSSION...
/319 PM CST FRI NOV 20 2009/
CLOUDS CONTINUE TO STREAM N-NEWD INTO MAINLY THE SRN HALF OF MO
AHEAD OF THE MID-UPPER LEVEL TROF OVER TX. LIGHT RAIN MOVING NEWD
INTO SWRN MO BUT IT APPEARS THAT MOST OF THIS RAIN WILL REMAIN S
OF THE CWA. SHOULD BE INCREASING CLOUD COVER THOUGH TGT INTO SAT
AS MODELS BRING LOW LEVEL MOISTURE CENTERED AROUND 850 MB IN
HEIGHT NWD. DESPITE INCREASING CLOUD COVER AND PLENTY OF DAYTIME
HEATING AND MIXING TDA ACROSS MOST OF THE CWA THERE SHOULD STILL
BE AT LEAST PATCHY FOG DEVELOPING LATE TGT. THE FOG SHOULD NOT BE
AS WIDESPREAD OR AS DENSE AS LAST NGT. LOW TEMPERATURES SHOULD
ALSO NOT BE QUITE AS COLD AS WELL. RAIN SHOULD REMAIN S OF THE CWA
THIS WEEKEND AS THE SRN MID-UPPER LEVEL TROF MOVES EWD THRU THE
GULF COAST REGION. THERE WILL ALSO BE A WEAKER MID-UPPER LEVEL TROF
WHICH WILL MOVE EWD THRU THE GREAT LAKES AND OHIO VALLEY REGIONS.
MAIN SFC RIDGE WILL BE CENTERED E OF THE CWA WITH MAINLY SELY SFC
WINDS THIS WEEKEND. HIGH TEMPERATURES WILL BE SIMILAR TO TODAY AND
ABOVE SEASONAL NORMALS. NAM MODEL GENERATES QPF OVER THE SERN HALF
OF THE CWA SUN NGT AHEAD OF A WEAK SHRTWV MOVING EWD THRU THE REGION
AND N OF A WEAK SFC LOW MOVING NWD THRU ERN AR. DISCOUNTED THIS AS
NO OTHER MODEL FITS THIS SOLUTION NOR DOES THE PREVIOUS NAM MODEL
RUNS GENERATE THIS RAIN SUN NGT. NEXT CHANCE OF RAIN SHOULD OCCUR
MON NGT AND TUE AS A STRONG MID-UPPER LEVEL TROF/LOW AND ASSOCIATED
CDFNT/SFC LOW MOVE EWD THRU THE REGION. STILL A LOT OF MODEL
UNCERTAINTY WITH THE POSITION OF THE UPPER LEVEL AND ASSOCIATED SFC
LOW AND HOW PROGRESSIVE THIS SYSTEM WILL BE. THE GFS MODEL CONTINUES
TO BE MORE PROGRESSIVE AND FURTHER N WITH THIS SYSTEM WHILE THE
ECMWF IS SLOWER AND FURTHER S. FOR NOW JUST INCLUDED CHANCE POPS FOR
MON NGT AND TUE...WITH COLDER TEMPERATURES FOR WED AND THU.
GKS
&&
.AVIATION...
/550 PM CST FRI NOV 20 2009/
FOR THE 00Z TAFS...MVFR CIGS FINALLY DISSIPATED/MOVED AWAY FROM
KUIN. IN THE MEANTIME...SC STARTING TO DEVELOP OVER SOUTHERN HALF OF
MISSOURI...WITH SOME CIRRUS BLANKETING THE AREA AS WELL. COVERAGE OF
THESE CLOUDS WILL DETERMINE FOG DEVELOPMENT FOR TONIGHT. FOR NOW
CONSIDERABLE MOISTURE REMAINS IN THE LOWER LEVELS AND THE FLOW IS
WEAK...GENERALLY A GOOD RECIPE FOR LOW STRATUS/FOG. SO KEPT PREVIOUS
FORECAST TO INDICATE THERE WILL BE SOME COOLING AND LOWERING
CIGS/VSYBS INTO IFR CAT DURING THE PREDAWN HOURS...BEFORE IMPROVING
DURING THE DAY ON SATURDAY.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 210205
AFDLSX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
805 PM CST FRI NOV 20 2009
.DISCUSSION...
/805 PM CST FRI NOV 20 2009/
OVERNIGHT ADJUSTMENTS HAVE BEEN MADE TO THE FORECAST IN LIGHT OF
THE RAPID DEVELOPMENT OF HIGH SC/LOW AC CLOUDS THAT HAVE DEVELOPED
PRIMARILY OVER THE I-70 CORRIDOR IN THE PAST FEW HOURS. THIS IS A
RESPONSE TO NARROW BUT INTENSE ISENTROPIC UPGLIDE MOST NOTICEABLE
AT THE 290K LEVEL. MODELS TAKE THIS LIFT AND MAINTAIN IT THRU THE
NIGHT AROUND THE I-70 CORRIDOR AND EVENTUALLY EXPAND IT INTO NERN
MO/WCNTRL IL. THESE CLOUDS SHOULD EFFECTIVELY KILL WIDESPREAD FOG
FORMATION FOR THE I-70 CORRIDOR...BUT FOR AREAS THAT CAN COOL
RAPIDLY ENOUGH IN THE FAR NRN FA AROUND QUINCY BEFORE THE CLOUDS
ROLL IN...AREAS OF FOG STILL EXPECTED TO FORM ALTHOUGH VSBYS WILL
LIKELY IMPROVE NEAR SUNRISE WHEN VSBYS ARE NORMALLY AT THEIR
WORST. SERN MO WILL BE JUST S OF THE BETTER ISENTROPIC UPGLIDE AND
SO WILL HAVE ENOUGH HOLES IN THE CLOUDS TO ALSO COOL OFF AND SO
HAVE ADDED AREAS OF FOG GIVEN THEIR RELATIVELY HIGH CROSSOVER
TEMPS IN THE MID 40S. MIN TEMP ADJUSTMENTS HAVE BEEN MADE TO
INCREASE BY SEVERAL DEGS FOR THE I-70 CORRIDOR BUT MAINTAINED THE
COOL PREVIOUS FORECAST FOR OTHER AREAS.
TES
&&
.AVIATION...
/550 PM CST FRI NOV 20 2009/
FOR THE 00Z TAFS...MVFR CIGS FINALLY DISSIPATED/MOVED AWAY FROM
KUIN. IN THE MEANTIME...SC STARTING TO DEVELOP OVER SOUTHERN HALF OF
MISSOURI...WITH SOME CIRRUS BLANKETING THE AREA AS WELL. COVERAGE OF
THESE CLOUDS WILL DETERMINE FOG DEVELOPMENT FOR TONIGHT. FOR NOW
CONSIDERABLE MOISTURE REMAINS IN THE LOWER LEVELS AND THE FLOW IS
WEAK...GENERALLY A GOOD RECIPE FOR LOW STRATUS/FOG. SO KEPT PREVIOUS
FORECAST TO INDICATE THERE WILL BE SOME COOLING AND LOWERING
CIGS/VSYBS INTO IFR CAT DURING THE PREDAWN HOURS...BEFORE IMPROVING
DURING THE DAY ON SATURDAY.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KSGF 210003
AFDSGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
603 PM CST FRI NOV 20 2009
...UPDATE TO AVIATION...
.DISCUSSION...
IT WAS A MILD AND RELATIVELY QUIET DAY OVER EXTREME SOUTHEAST KANSAS
AND THE MISSOURI OZARKS. TEMPERATURES WERE GENERALLY IN THE UPPER
50S AND LOWER 60S...UNDER MOSTLY CLOUDY SKIES AND LIGHT WINDS. AN
INVERTED SURFACE TROUGH WAS POSITIONED ACROSS FAR SOUTHWEST
MISSOURI...WHICH BECAME A FOCUS FOR SOME SPRINKLES AND LIGHT RAIN
SHOWERS. THESE SHOWERS WERE CONFINED TO MCDONALD...NEWTON...AND
BARRY COUNTIES. ALL OTHER LOCATIONS REMAINED DRY.
THIS SURFACE TROUGH WILL REMAIN POSITIONED OVER THE REGION
TONIGHT...CAUSING THE LOWER TROP TO BECOME VERY SATURATED BY EARLY
SATURDAY MORNING. POINT FORECAST SOUNDINGS OVER THE WESTERN HALF OF
THE CWA SUGGESTS THE POTENTIAL FOR SOME STRATUS BUILD DOWN. I WILL
ADD AREAS OF DENSE FOG TO THIS AREA FROM 9Z - 15Z. DUE TO EXISTING
CLOUD COVER...I OPTED NOT TO ISSUE A DENSE FOG ADVISORY JUST
YET...AND WILL ALLOW THE EVENING SHIFT TO MONITOR AND PINPOINT WHICH
COUNTIES MAY NEED ONE. WEAK SURFACE WINDS WILL ALSO BE A CONDUCIVE
INGREDIENT FOR DENSE FOG.
LIGHT RAIN CHANCES WILL ALSO ACCOMPANY THE INVERTED SURFACE TROUGH.
AGAIN...MOST AREAS TONIGHT WILL REMAIN DRY...HOWEVER...LOCATIONS
ACROSS FAR SOUTHERN MISSOURI WILL EXPERIENCE THESE SPRINKLES AND
LIGHT RAIN. WILL CONTINUE WITH LIGHT RAIN CHANCES FOR AREAS SOUTH
OF HIGHWAY 60...AND EAST OF HIGHWAY 71...WHICH ENCOMPASSES FAR
SOUTHERN MISSOURI.
AN UPPER LEVEL DISTURBANCE WAS TRANSLATING ACROSS THE INTERSTATE 20
CORRIDOR OF TEXAS THIS AFTERNOON. THIS FEATURE WILL SHIFT TO THE
EAST NORTHEAST SATURDAY AND SATURDAY NIGHT...CAUSING A SHIELD OF
LIGHT RAIN TO DEVELOP OVER ARKANSAS...SOUTHEAST MISSOURI...AND
WESTERN KENTUCKY. THERE IS A SLIGHT CHANCE THAT AREAS OF HOWELL OR
OREGON COUNTY MAY BE CLIPPED BY THIS SHIELD OF RAIN LATE SATURDAY
NIGHT OR SUNDAY MORNING. IF RAIN DOES OCCUR IN THESE AREAS...THEN
ONLY LIGHT AMOUNTS ARE EXPECTED. THE REST OF THE REGION WILL REMAIN
DRY AND MILD...WITH HIGHS SATURDAY AND SUNDAY REACHING THE LOWER
60S. A MIX OF SUN AND CLOUDS CAN BE EXPECTED THROUGH MUCH OF THE
WEEKEND.
ZONAL FLOW WILL GIVE WAY TO A DEEPENING UPPER LEVEL LOW PRESSURE
SYSTEM MONDAY NIGHT INTO EARLY TUESDAY MORNING. THIS FEATURE WILL
ALSO FORCE A COLD FRONT INTO THE REGION...WHICH WILL CAUSE A DECENT
COOL DOWN FOR THE MIDDLE OF NEXT WEEK. AS A MATTER OF FACT...THE
UPPER PATTERN BECOMES EVEN MORE AMPLIFIED THROUGH LATE NEXT WEEK AS
A STRONG RIDGE OVER THE MOUNTAIN WEST...CAUSES A PIPELINE OF
CANADIAN AIR TO PLUNGE SOUTHWARD INTO THE NATIONS MID SECTION.
SEVERAL SHORTWAVE TROUGHS WILL MIGRATE THROUGH THIS WAVE
INFLECTION...REINFORCING A CLOUDY AND COOL WEATHER REGIME FOR THE
OZARKS. DESPITE THIS COLD AND DREARY PATTERN...THERE ARE NO
INDICATIONS FROM MODEL OUTPUT THAT WOULD SUGGEST FROZEN
PRECIPITATION THROUGH THE NEXT 7 DAYS.
CRAMER
&&
.AVIATION...
FOR THE 21/0000Z KSGF/KJLN/KBBG TAFS...A WEAK SFC TROUGH EXTENDS
FROM EASTERN OK INTO SOUTHERN MO. VFR CEILINGS WERE COMMON OVER
SOUTHERN MO...WITH MVFR AND IFR CEILINGS FARTHER SOUTH INTO NW AR
AND EASTERN OK. A WEAK SHORTWAVE MOVING THROUGH THE AREA HAS
PROVIDED ENOUGH LIFT FOR EXTENSIVE CLOUDS AND LIGHT PRECIP...BUT
LOWER CLOUDS EXTEND WELL BACK TO THE WEST...EVEN IN THE WAKE OF
THE EXITING SHORTWAVE. PROGGED SOUNDINGS SHOW VARYING AMOUNTS OF
CLOUDS IN THE LOWER LEVELS. SHORT RANGE ENSEMBLES (SREF) SEEM TO
BE PEGGING CLOUDS RATHER THAN FOG OVERNIGHT INTO SATURDAY...AND
WENT CLOSER TO SREF GUIDANCE WITH MAINLY MVFR CEILINGS AND
MVFR/BRIEF IFR CATEGORY FOG. SHOULD SEE A GRADUALLY LIFTING MVFR/VFR
CEILING BY LATE MORNING AND AFTERNOON ON SATURDAY. DSA
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
000
FXUS63 KLSX 202350
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
550 PM CST FRI NOV 20 2009
.DISCUSSION...
/319 PM CST FRI NOV 20 2009/
CLOUDS CONTINUE TO STREAM N-NEWD INTO MAINLY THE SRN HALF OF MO
AHEAD OF THE MID-UPPER LEVEL TROF OVER TX. LIGHT RAIN MOVING NEWD
INTO SWRN MO BUT IT APPEARS THAT MOST OF THIS RAIN WILL REMAIN S
OF THE CWA. SHOULD BE INCREASING CLOUD COVER THOUGH TGT INTO SAT
AS MODELS BRING LOW LEVEL MOISTURE CENTERED AROUND 850 MB IN
HEIGHT NWD. DESPITE INCREASING CLOUD COVER AND PLENTY OF DAYTIME
HEATING AND MIXING TDA ACROSS MOST OF THE CWA THERE SHOULD STILL
BE AT LEAST PATCHY FOG DEVELOPING LATE TGT. THE FOG SHOULD NOT BE
AS WIDESPREAD OR AS DENSE AS LAST NGT. LOW TEMPERATURES SHOULD
ALSO NOT BE QUITE AS COLD AS WELL. RAIN SHOULD REMAIN S OF THE CWA
THIS WEEKEND AS THE SRN MID-UPPER LEVEL TROF MOVES EWD THRU THE
GULF COAST REGION. THERE WILL ALSO BE A WEAKER MID-UPPER LEVEL TROF
WHICH WILL MOVE EWD THRU THE GREAT LAKES AND OHIO VALLEY REGIONS.
MAIN SFC RIDGE WILL BE CENTERED E OF THE CWA WITH MAINLY SELY SFC
WINDS THIS WEEKEND. HIGH TEMPERATURES WILL BE SIMILAR TO TODAY AND
ABOVE SEASONAL NORMALS. NAM MODEL GENERATES QPF OVER THE SERN HALF
OF THE CWA SUN NGT AHEAD OF A WEAK SHRTWV MOVING EWD THRU THE REGION
AND N OF A WEAK SFC LOW MOVING NWD THRU ERN AR. DISCOUNTED THIS AS
NO OTHER MODEL FITS THIS SOLUTION NOR DOES THE PREVIOUS NAM MODEL
RUNS GENERATE THIS RAIN SUN NGT. NEXT CHANCE OF RAIN SHOULD OCCUR
MON NGT AND TUE AS A STRONG MID-UPPER LEVEL TROF/LOW AND ASSOCIATED
CDFNT/SFC LOW MOVE EWD THRU THE REGION. STILL A LOT OF MODEL
UNCERTAINTY WITH THE POSITION OF THE UPPER LEVEL AND ASSOCIATED SFC
LOW AND HOW PROGRESSIVE THIS SYSTEM WILL BE. THE GFS MODEL CONTINUES
TO BE MORE PROGRESSIVE AND FURTHER N WITH THIS SYSTEM WHILE THE
ECMWF IS SLOWER AND FURTHER S. FOR NOW JUST INCLUDED CHANCE POPS FOR
MON NGT AND TUE...WITH COLDER TEMPERATURES FOR WED AND THU.
GKS
&&
.AVIATION...
/550 PM CST FRI NOV 20 2009/
FOR THE 00Z TAFS...MVFR CIGS FINALLY DISSIPATED/MOVED AWAY FROM
KUIN. IN THE MEANTIME...SC STARTING TO DEVELOP OVER SOUTHERN HALF OF
MISSOURI...WITH SOME CIRRUS BLANKETING THE AREA AS WELL. COVERAGE OF
THESE CLOUDS WILL DETERMINE FOG DEVELOPMENT FOR TONIGHT. FOR NOW
CONSIDERABLE MOISTURE REMAINS IN THE LOWER LEVELS AND THE FLOW IS
WEAK...GENERALLY A GOOD RECIPE FOR LOW STRATUS/FOG. SO KEPT PREVIOUS
FORECAST TO INDICATE THERE WILL BE SOME COOLING AND LOWERING
CIGS/VSYBS INTO IFR CAT DURING THE PREDAWN HOURS...BEFORE IMPROVING
DURING THE DAY ON SATURDAY.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KEAX 202350
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
550 PM CST FRI NOV 20 2009
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
MAIN CONCERN THROUGH THE SHORT TERM WILL BE WITH FOG POTENTIAL
TONIGHT INTO TOMORROW MORNING. WEAK SFC RIDGE REMAINS STATIONED
ACROSS THE CWA THIS AFTERNOON AND WILL LIKELY REMAIN IN PLACE THROUGH
THIS EVENING. THIS WILL LIKELY LEAD TO CONTINUED LIGHT AND VARIABLE
SFC WINDS THROUGH AT LEAST THE EARLY PART OF TONIGHT. BROAD TROUGH
WILL ENGULF THE WESTERN CONUS TONIGHT LEADING TO PRESSURE FALLS ALONG
THE LEE OF THE ROCKIES. THIS WILL BRING ABOUT A MORE SOUTHERLY LLVL
FLOW REGIME BY LATE TONIGHT INTO THE MORNING HOURS. COMPLICATED
FORECAST DEALING WITH THE POSSIBILITY OF DENSE FOG OVERNIGHT AS A
COMBINATION OF RADIATIONAL AND ADVECTION PROCESSES WILL LIKELY BE AT
WORK. CLOUD COVER ACROSS THE SOUTHERN COUNTIES HAS ALL BUT DISSIPATED
ATTM WITH THE BULK OF THE REMAINING ACTIVITY CONFINED TO THE SOUTHERN
PLAINS AND OZARKS. BELIEVE THE MAJORITY OF THE CWA WILL REMAIN FAIRLY
CLEAR THROUGH THIS EVENING AND EARLY NIGHTTIME HOURS ALLOWING FOR
EFFICIENT RADIATIONAL COOLING TO COMMENCE. THIS WILL ALLOW THE
BOUNDARY LAYER TO COME CLOSE TO SATURATION AND PERHAPS RESULT IN
AREAS OF FOG FORMATION BY MIDNIGHT. HOWEVER LATER TONIGHT...A WEAK
WARM FRONT WILL LIFT NORTHWARD INTO THE SOUTHERN CWA ALLOWING LLVL
MOISTURE AND CLOUD COVER TO MAKE A DECENT SURGE NORTHWARD. THIS
SHOULD BRING ABOUT ADDITIONAL FOG DEVELOPMENT ACROSS THESE AREAS
TOWARDS THE EARLY MORNING HOURS. HOWEVER AS THIS OCCURS...SFC FLOW
WILL LIKELY INCREASE A BIT AS THE SFC RIDGE BECOMES BETTER
ESTABLISHED ACROSS THE OHIO VALLEY AND PRESSURE CONTINUE TO FALL
ACROSS THE HIGH PLAINS. THEREFORE...UNCERTAINTY EXISTS AS TO THE
EXTENT AND DENSITY OF FOG WHERE RADIATIONAL PROCESSES DOMINATE. WILL
INCLUDE AREAS OF FOG ACROSS THE ENTIRE CWA OVERNIGHT AND LEAVE IT TO
LATER SHIFTS TO HOIST ANY ADVISORIES AS MORE CONFIDENCE IN
LOCATION...TIMING...AND DENSITY IS GAINED. FOG WILL LIKELY LINGER
THROUGH THE MID MORNING HOURS BEFORE GRADUALLY BURNING OFF.
BY TOMORROW...LEE SIDE TROUGHING WILL LEAD TO INCREASED SOUTHERLY
LLVL FLOW AND SLIGHTLY WARMER TEMPS ACROSS MOST AREAS. SFC FRONT WILL
SLIDE INTO EASTERN NEBRASKA/CENTRAL KANSAS BY SATURDAY NIGHT INTO
SUNDAY MORNING BEFORE STALLING AS NEXT SHORT WAVE TROUGH DIVES INTO
THE ROCKIES AND FURTHER PRESSURE FALLS TAKE SHAPE ACROSS THE HIGH
PLAINS. THIS WAVE WILL THEN PUSH INTO THE PLAINS ON SUNDAY LIKELY
BRINGING THE WEAK SFC BOUNDARY CLOSER TO THE CWA AND BRING AT LEAST A
SLIGHT CHC OF SHOWERS TO THE NORTHWESTERN COUNTIES DURING THE DAY.
DEROCHE
MEDIUM RANGE (MONDAY THROUGH FRIDAY)...
FOR NEXT WORK WEEK THE PRIMARY WEATHER ISSUE WILL BE THE DEVELOPMENT
OF A PROGRESSIVE TROUGH THAT WILL POSSIBLY BRING SOME PRECIPITATION
TO THE CENTRAL PLAINS. MID RANGE MODELS ARE CURRENTLY ADVERTISING A
SERIES OF SHORTWAVES TO MOVE THROUGH THE PLAINS OVER THE WEEKEND AND
NEXT WEEK WITH A MODESTLY LARGE TROUGH DEVELOPING IN RESPONSE ACROSS
THE CENTRAL PLAINS MONDAY/TUESDAY. MODELS HAVE BE CONSISTENT IN
ADVERTISING ITS DEVELOPMENT...BUT THE TIMING IS A BIT OF AN ISSUE.
LATEST RUN OF THE THE GFS CONTINUES TO BE THE OUTLIER AS IT IS THE
FASTEST SOLUTION. GEM/ECMWF/UKMET ALL HAVE THE SYSTEM MOVING MORE
SLOWLY THROUGH THE PLAINS...WHICH SEEMS REASONABLE DUE TO THE
STRENGTH OF THE JET ROUNDING ITS BASE.
SO...WHILE TIMING PREFERENCE IS HEDGED TOWARDS THE ECMWF/UKMET/GEM
COMBINATION...THE TRACK OF THE TROUGH ACROSS THE PLAINS IS FAIRLY
CHAOTIC. THE GFS IS ADVERTISING THE INITIAL TROUGH DIGGING STRAIGHT
THROUGH THE NORTHERN PLAINS INTO MISSOURI...WITH A SECONDARY WAVE
DIGGING INTO ITS BACK SIDE AND RELOADING THE TROUGH FOR THURSDAY.
THE GEM AND ECMWF KEEP THE FEATURE MORE AS ONE COHERENT SHORT LIVED
CUTOFF LOW AS IT MOVES INTO AND THEN BACK OUT OFF THE PLAINS. HAVE
OPTED NOT TO ADJUST THE FORECAST TOO MUCH DUE TO THE VERITY AND THE
LACK OF CONFIDENCE IN THE CURRENT SET OF SOLUTIONS. CHANCE POPS FOR
PORTIONS OF THE FORECAST AREA MONDAY THROUGH TUESDAY SEEMS TO STILL
BE A GOOD IDEA...THOUGH DETAILS ARE STILL A BIT VAGUE. GENERAL TREND
WOULD AT LEAST INDICATE THAT...GIVEN THE SOURCE REGION OF OF THE AIR
MASS BEHIND THE TROUGH...IT SHOULD BE TOO WARM FOR ANY FROZEN
PRECIPITATION. SO...FOR NOW HAVE SIMPLY KEPT OUR GOING PRECIPITATION
AS RAIN. OTHERWISE...REMAINDER OF THE WORK WEEK CURRENTLY LOOKS DRY
AS SOME FORM OF RIDGING WILL BEGIN TO BUILD IN FROM THE WEST...
PUSHING THE NORTHWEST FLOW BEHIND THE TROUGH OFF TO THE EAST.
CUTTER
&&
.AVIATION...
FOR THE 00Z TAFS...CONCERN ONCE AGAIN IS THE POTENTIAL FOR FOG.
EARLIER GUIDANCE SUGGESTED THAT THE LOW CLOUD DECK IN OKLAHOMA AND ARKANSAS
WOULD MOVE NORTH INTO THE TERMINALS. LATEST STLT LOOP SHOWS THE
PROGRESSION OF THE LOW CLOUD DECK WAS QUITE SLOW. LATEST GUIDANCE
SUGGEST THAT THE LOW CLOUD DECK WILL NOT MAKE IT THIS FAR NORTH.
THEREFORE... THE POTENTIAL FOR IFR FOG IS INCREASING. SREP GUIDANCE
PROBABILITIES WERE ALSO RIGHT AT THE THRESHOLD FOR DENSE FOG...MAINLY
AT MCI AND STJ. ONE FLY IN THE OINTMENT IS THE INTERVALS OF AC THAT
IS POSSIBLE TONIGHT. REGARDLESS...GIVEN THE MOSTLY CLEAR
SKIES...LIGHT WINDS...MOIST AIR MASS AND WET GROUND...HAVE DECIDED TO
LOWER VSBYS FOR TONIGHTS FORECAST...ESPECIALLY AT KMCI AND KSTJ. IT
IS POSSIBLE THAT VSBYS MAY DROP TO THE VLIFR CATEGORY FOR KMCI AND
KSTJ. THE FOG WILL BE SLOW TO LIFT SAT MORNING DUE TO POOR INSOLATION
AND A STEADY INCREASE IN LOW LEVEL MOISTURE. IN ADDITION...THE
MODELS SUGGEST THAT A MVFR/IFR CLOUD DECK WILL FORM AFTER FOG
DISSIPATION.
DB
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
| 
