[top]
000
FXUS63 KOAX 212130
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
330 PM CST SAT NOV 21 2009
.SHORT TERM...TONIGHT THROUGH TUESDAY
PLEASANT WEATHER CONTINUES TODAY AHEAD OF MORE ACTIVE AND COOLER
PATTERN DEVELOPING FOR THE WEEK. SUBJECTIVE 12Z UPPER AIR ANALYSIS
INDICATES DIGGING UPPER TROUGH IN THE WRN US...WITH 500 MB HT FALLS
OF 150 M CENTERED IN NRN MT. UPPER RIDGE EXTENDED FROM ERN KS
THROUGH IA INTO CNTRL ONT...AND UPPER LOW WAS ALSO CENTERED IN NRN
TX. 850MB LOW WAS DEVELOPING IN RESPONSE TO STRENGTHENING UPPER
TROUGH...WITH LOW CENTERED IN NRN AB AND COLD FRONT EXTENDING
THROUGH THE ROCKIES. STRONG 850MB WARM AIR ADVECTION WAS PRESENT
FROM THE HIGH PLAINS INTO THE DAKOTAS...WITH 850MB MOISTURE TONGUE
FROM ERN TX INTO ERN KS/WRN MO. SFC PRESSURE GRADIENT WAS
TIGHTENING OVER THE CNTRL PLAINS WITH SFC LOW DEVELOPING ON THE
SASK/MB BORDER...AND SECONDARY LOW IN ERN CO.
MAIN FORECAST CONCERN LIES IN EVOLUTION OF DIGGING UPPER LOW AND
ASSOCIATED WEATHER IMPACTS MON NT/TUES...WITH PESKY FOG/DRIZZLE/LT
RAIN/STRATUS IN THE MEANTIME. LOW-LEVEL MOISTURE ADVECTION THAT HAS
ALLOWED FOG/STRATUS DEVELOPMENT THE LAST SEVERAL NIGHTS CONTINUES.
WITH INCREASED SFC WINDS TONIGHT...THINK DENSE FOG WILL BE LESS
OF A CONCERN THAN THE LAST COUPLE NIGHTS. AMPLE LOW-LEVEL MOISTURE
SHOULD KEEP STRATUS AROUND THOUGH...AND MOISTURE COMBINED WITH
SOME WEAK LIFT AS Q-VECTOR CONVERGENCE INCREASES SHOULD ALLOW
A LITTLE DRIZZLE. SFC DEWPOINTS ARE MUCH HIGHER THAN
YESTERDAY...WHICH WILL KEEP TEMPS MUCH HIGHER TONIGHT AND PROVIDE
A WARMER START TMRW. WITH CONTINUED WARM AIR ADVECTION
TMRW...TEMPS SHOULD EASILY REACH INTO THE 50S IN ALL BUT PERHAPS
THE NWRN CWA DESPITE CLOUDS. LEAD WAVE IS PROGGED TO EJECT ACROSS
THE CNTRL US ON SUN...DRAGGING A WEAK COLD FRONT INTO CNTRL TO
NERN NEB BEFORE IT WASHES OUT AS RETURN FLOW DEVELOPS IN ADVANCE
OF MAIN UPPER WAVE. WITH SOME UPPER LIFT AND PRESENCE OF A COLD
FRONT...COULD SEE A LITTLE LIGHT RAIN NEAR THE FRONT...AND HAVE
TWEAKED POPS TO ADJUST TO POSSIBLE FRONTAL POSITION. SHOULD SEE A
BREAK IN LT RAIN CHANCES SUN NT/MON AS INITIAL FRONT WEAKENS AND
MAIN UPPER LOW/COLD FRONT APPROACHES...THOUGH WITH ABUNDANT LOW-
LEVEL MOISTURE...STILL EXPECT QUITE A FEW CLOUDS. AGAIN...THINK
WINDS SHOULD BE JUST ENOUGH TO KEEP DENSE FOG AT BAY.
WHILE THERE IS STILL SOME DISAGREEMENT AMONG MODELS REGARDING UPPER
LOW POSITION WHEN IT CLOSES AND DEPTH AS IT DIVES OUT OF THE NRN
ROCKIES INTO THE CNTRL PLAINS...AGREEMENT IS IMPROVING AND MODELS
ARE TRENDING TOWARD A COMMON SOLUTION. GFS REMAINS SOMEWHAT FASTER
THAN OTHER SOLUTIONS...THUS CONTINUE TO LEAN TOWARD SLOWER
ECMWF/GEM. MAIN DIFFERENCE AT THIS POINT IS IN LOW- TO MID-LEVEL
TEMP PROFILE...WHICH /OF COURSE/ SIGNIFICANTLY IMPACTS THE EXPECTED
PRECIP TYPE. ECMWF HAS BEEN WARMER THAN GFS/GEM AND APPEARS WARMER
THAN THE 18Z NAM HEADING INTO MON NT...WRAPPING IN LESS COLD AIR IN
WAKE OF THE UPPER LOW. FOR NOW...HAVE TRENDED TOWARD A COMPROMISE
SOLUTION...LEANING SLIGHTLY TOWARD THE COLDER SOLUTIONS AS LIFT
ASSOCIATED WITH STRONG UPPER LOW SHOULD BE ABLE TO INDUCE SOME
DYNAMICAL COOLING. THUS...HAVE INTRODUCED MORE SNOW INTO THE
GRIDS...WITH SOME LIGHT ACCUM FROM CNTRL TO NERN NEB ON MON NT
/CURRENT SNOW GRIDS END THERE...BUT CURRENT PROG WOULD INDICATE SOME
ACCUM ON TUES DAYTIME AS WELL/. HAVE KEPT MON NT TEMPS CLOSE TO
WET-BULB VALUES...AND LOWERED MAX TEMPS ON TUES SIGNIFICANTLY AS
STRONG COLD AIR ADVECTION /NOT TO MENTION CLOUDS AND PRECIP/ SHOULD
HINDER ANY WARMING.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
MEDIUM RANGE MODELS SHOWING VARYING DEGREES OF DIFFERENCE WITH
SHORTWAVE ENERGY DROPPING OUT OF SCNTRL CANADA TUESDAY NIGHT AS WELL
AS AMPLIFYING WRN CONUS RIDGE HEADING INTO NEXT WEEKEND. AS FOR THE
CANADIAN WAVE DROPPING INTO THE LOWER 48 MID WEEK...MODELS SIMILAR
ADVERTISING A COLD FRONT WILL PENETRATE THE NRN STATES BUT VARY WRT
PLACEMENT OF COLD AIRMASS. THE GFS IS THE MOST AGGRESSIVE PUSHING IT
THRU THE DAKOTAS AND DOWN THE UPPER MID WEST/MID MS CLY REGION WHILE
THE GEM TAKES A SWD TRACK JUST A BIT FATHER EAST OF THE REGION.
MEANWHILE THE ECMWF HOLDS OFF PUSHING THE BRUNT OF THE COLD AIRMASS
TILL ABOUT EARLY WEDNESDAY EVENING AND WITH A TRACK MORE TOWARD THE
GREAT LAKES REGION. FOR NOW WILL OPT TO TEMPER ADJUSTING TEMPS
DOWNWARD ON WEDNESDAY. NEVERTHELESS...ENOUGH CAUSE TO TO INCLUDE
SMALL CHANCE FOR RA OR SN TUESDAY NIGHT WITH STRONG DYNAMIC FORCING
COMING IN CLOSE VICINITY OF THE CWA. OTHERWISE...DRY CONDITIONS
WITH ABOVE NORMAL TEMPS ON TAP THE REST OF THE FCST PD WHEN A
BUILDING UPPER RIDGE EVENTUALLY ENVELOPS THE PLAINS.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
GENERALLY VFR CONDITIONS CAN BE EXPECTED THROUGH 00Z...HOWEVER
OCCASIONAL MVFR CIGS NEAR FL025 WILL AFFECT EASTERN NEBRASKA AT
TIMES. MVFR TO IFR CIGS ARE EXPECTED TO SPREAD NORTH FROM EASTERN
KANSAS TO KLNK...KOMA AND KOFK BETWEEN 00Z AND 06Z...WITH
DETERIORATING CONDITIONS EXPECTED AFTER 06Z. CIGS BELOW FL010 AND
OCCASIONAL VISIBILITIES BELOW 3SM IN FOG ARE LIKELY BETWEEN 08Z AND
18Z SUNDAY.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...MAYES
LONG TERM...DEE
AVIATION...DERGAN
[top]
000
FXUS63 KGID 212106
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
306 PM CST SAT NOV 21 2009
.SHORT TERM...TONIGHT THROUGH 12Z MONDAY. QUESTION FOR THIS FORECAST
PERIOD IS TEMPERATURES AND WEATHER. CLOUDS HANGING IN THERE THIS
AFTERNOON AND EXPECT TO SEE THEM BREAK UP SOME AT SUNSET...BUT WITH
GOOD SOUTH FLOW AND DEW POINTS IN THE MIDDLE TO UPPER 40S CONTINUING
TO STREAM NORTH...EXPECT CLOUDS TO RETURN BY 22/06Z. WITH CLOUD
COVER AND MOIST AIRMASS...OVERNIGHT LOWS SHOULD NOT DROP OFF TOO
FAR. GUIDANCE HAS LOWS IN THE 30S MOST AREAS. WILL OPT FOR READINGS
IN THE UPPER 30S WEST TO LOWER 40S EAST. WOULD ALSO EXPECT FOG TO
DEVELOP ACROSS THE AREA ALONG WITH SOME PATCHY DRIZZLE.
CLOUDS AND FOG/DRIZZLE WILL BE SLOW TO DISSIPATE ON MONDAY AND WILL
EXPECT A MOSTLY CLOUDY DAY. THIS WILL IMPACT HIGH TEMPERATURES GIVEN
THAT LOWS WILL BE WARMER THAN THE PAST FEW DAYS...SHOULD SEE MAX
TEMPS AROUND 50 MOST AREAS. MODEL SOUNDINGS DO START TO DRY THINGS
OUT A LITTLE IN THE AFTERNOON SO ANY PRECIP SHOULD BE OVER BY
MID-DAY.
WEAK SURFACE BOUNDARY COMES THROUGH SUNDAY NIGHT AND WILL HELP TO
DRY THINGS DOWN JUST A BIT AND ALLOW TEMPS TO FALL INTO THE 30S.
WITH RATHER LIGHT WINDS...EVEN WITH SOME DRYING...WILL SEE SOME
PATCHY FOG AROUND.
.LONG TERM...12Z MONDAY THROUGH SATURDAY. MAIN FORECAST CONCERNS
WILL BE CHANCE FOR PRECIPITATION MONDAY THROUGH TUESDAY NIGHT AND
TEMPERATURES.
AN UPPER LEVEL LOW MOVES THROUGH THE PLAINS MONDAY THROUGH TUESDAY
NIGHT. MODELS HAVE SLIGHTLY DIFFERENT TIMING AND LOCATION OF THE LOW
AS IT MOVES THROUGH THE AREA...BUT BASICALLY THE LOW MOVES OUT OF
THE NORTHERN ROCKIES EARLY MONDAY AND DRIFTS THROUGH SOUTH DAKOTA OR
NEBRASKA MONDAY NIGHT TO AROUND IOWA BY TUESDAY EVENING...DEPENDING
ON THE MODEL. WILL TREND TOWARD THE 12Z ECMWF BUT WILL MAKE A FEW
MODIFICATIONS TO IT.
AS THE UPPER LOW MOVES OUT OF THE ROCKIES...A COLD FRONT WILL MOVE
THROUGH THE FORECAST AREA MONDAY MORNING. ALONG THE COLD FRONT THERE
WILL BE A CHANCE FOR SOME LIGHT RAIN FOR MONDAY. IN THE MORNING THE
BEST CHANCE WILL BE FURTHER NORTH BUT SHOULD SPREAD ACROSS THE AREA
AS THE UPPER LOW SLIDES IN. MONDAY NIGHT THE COOLER AIR IS PULLED
INTO THE AREA AS THE LOW MOVES THROUGH. MODELS ARE DIVIDED ON HOW
MUCH COLD AIR GETS INTO THE AREA...BUT IF THE LOW IS FURTHER SOUTH
AS THE ECMWF...THEN IT SHOULD BE COLD ENOUGH. EXPECT THAT THE RAIN
WILL MIX WITH THEN CHANGE TO SNOW EARLY IN THE EVENING. IN THE EAST
IT MAY STAY A MIX OF RAIN AND SNOW SINCE THE COLDER AIR WILL BE IN
THE WEST. ON TUESDAY THE LOW STARTS TO MOVE TO THE EAST BUT EXPECT
THAT THERE WILL BE SOME WRAP AROUND PRECIPITATION WITH THIS. THE
COOLER AIR LINGERS IN THE AREA AND MUCH OF THE AREA WILL HAVE SNOW
ESPECIALLY IN THE MORNING BUT AS TEMPERATURES WARM UP IN THE
AFTERNOON THE SNOW MAY MIX WITH SOME RAIN ESPECIALLY IN THE SOUTH. A
LITTLE OF THE WRAP AROUND PRECIPITATION LINGERS TUESDAY NIGHT IN THE
NORTHEAST...BUT IT SHOULD BE COMING TO AN END.
THE REMAINDER OF THE WEEK SHOULD BE DRY AS A SHORT WAVE RIDGE BUILDS
INTO THE AREA. AS THE UPPER LOW MOVES TOWARD THE GREAT LAKES A SHORT
WAVE SPINS AROUND THE LOW INTO THE EASTERN PART OF THE FORECAST
AREA. THERE MAY BE A FEW MORE CLOUDS BUT TEMPERATURES AT 850MB ALSO
COOL OFF A LITTLE SO DO NOT EXPECT A BIG WARM UP FOR WEDNESDAY. AS
THE RIDGE BUILDS INTO THE AREA ON THURSDAY TEMPERATURES START TO
REBOUND...BUT THURSDAY NIGHT THE WARM UP IS TAKING SHAPE WITH WARM
ADVECTION AND TEMPERATURES AT 850 MB WARMING ABOUT 4 TO 6 DEGREES C
IN 12 HOURS. THE UPPER RIDGE MOVES TO THE EAST SATURDAY AND THE WARM
ADVECTION DECREASES. SO TEMPERATURES WILL BE COOLER BUT STILL BE
AROUND AVERAGE.
&&
.PREV DISCUSSION... /ISSUED 1120 AM CST SAT NOV 21 2009/
AVIATION...18Z KGRI TAF. LOW CLOUDS HAVE SPREAD INTO SOUTHERN
NEBRASKA ON THE RETURN OF SOUTHERLY SURFACE FLOW. WITH DEWPOINTS
INTO THE MIDDLE TO UPPER 40S TO THE SOUTH...DO NOT SEE CONDITIONS
CHANGING MUCH THIS AFTERNOON. DO EXPECT A BRIEF PERIOD AFTER SUNSET
OF THE CLOUDS TO BREAK...BUT CONTINUED SOUTHERLY FLOW TONIGHT WILL
RETURN THE LOW CIGS. DO EXPECT SOME FOG AND SOME LIGHT DRIZZLE
AROUND SUNRISE SUNDAY WITH CIGS AOB OVC010 AND VSBYS AOB 1SM.
CONDITIONS WILL SLOWLY IMPROVE DURING THE DAY SUNDAY...BUT WILL
REMAIN IFR FOR THE REMAINDER OF THE FORECAST PERIOD. -KISNER
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
[top]
000
FXUS63 KLBF 212105
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
305 PM CST SAT NOV 21 2009
.DISCUSSION...
A PACIFIC COLD FRONT IS APPROACHING THE FCST AREA THIS AFTN. THE
FRONT IS FCST TO DROP THROUGH THE FCST AREA OVERNIGHT AND LIFT NORTH
ON SUNDAY. EARLIER FCSTS FOR STRATUS AND FOG ARE ON HOLD AS THIS
FRONT SHOULD PUSH EAST OF THE FCST AREA AND APPEARS TO BE DRYING
OUT THE FCST AREA. THE 18Z NAM IS PULLING MOISTURE WEST THIS EVENING
TO NEAR KLBF SO IT WILL BE CLOSE.
THE MODELS HAVE COME INTO SOMEWHAT BETTER AGREEMENT ON THE STORM
SYSTEM FCST TO AFFECT THE CNTL PLAINS MONDAY AND TUESDAY. THE
ECMWF...NOGAPS AND UKMET ARE TRACKING THE H7 LOW EAST ACROSS NRN KS
WHILE THE NAM12...GFS...GFS ENSEMBLE...SREF AND GEM TRACK THE
DISTURBANCE THROUGH THE UPPER MISSOURI BASIN. THE ECMWF DEEPENS THE
STORM ACROSS EASTERN AND CENTRAL NEB WHILE SOME OF THE OTHER MODELS
DEEPEN THE SYSTEM OVER IA. SOME MODELS DONT DEEPEN THE SYSTEM AT
ALL. THE 250 MB JET IS LESS THAN 100KT AS IT CROSSES THE CNTL PLAINS.
THE DISTURBANCE IS STILL ACROSS THE NORTH PACIFIC BUT IS FCST TO BE
COME ASHORE OVER THE PAC NW COAST SUNDAY MORNING. THUS IN 24 HOURS
THE DISTURBANCE SHOULD BE PICKED UP BY THE UPPER AIR NETWORK AND THE
MODELS SHOULD BE IN BETTER AGREEMENT. OVERALL THERE HAS BEEN A NET
MODEL SOLN CONVERGENCE AND THE CONSENSUS IS FOR THE STORM TO AFFECT
NORTHEAST NEB WITH HEAVY SNOW AND STRONG WINDS MONDAY NIGHT THROUGH
TUESDAY MORNING. HPC SUGGESTED 4 TO 8 INCHES FROM NERN NEB ACROSS
SERN SD AND INTO SWRN MN. 2 TO 4 INCHES OF SNOW COULD FALL ALONG
HIGHWAY 281 ACROSS NCNTL NEB. THIS OFFICIAL FCST USES A 50 PERCENT
BLEND OF THE 12Z ECMWF AND 12Z NAM12 WHICH IS WHAT HPC USED FOR THEIR
SNOWFALL FCST.
THE MODELS ARE WRAPPING A STRONG PACIFIC COLD FRONT INTO THE STORM
PRODUCING AN OCCLUDED LOW NEAR KOMA TUESDAY MORNING. 850MB WINDS ARE
FCST TO INCREASE TO 40 TO 55KT MONDAY NIGHT ACROSS CNTL AND ERN NEB
WITH 500M AGL WINDS INCREASING TO 35 TO 40KT. THE COMBINATION OF WIND
AND SNOW FALLING AT NIGHT COULD PRODUCE A WINTER STORM CONDITION.
AS THE PACIFIC FRONT MOVES EAST MONDAY...THE NAM AND GFS INDICATE
RAIN SHOULD MIX WITH OR CHANGE TO WET SNOW WEST OF HIGHWAY 83.
TEMPERATURES BEHIND THE FRONT MONDAY NIGHT AND TUESDAY SHOULD BE COLD
ENOUGH FOR SNOW ACROSS ALL OF THE FCST AREA.
THE STORM SHOULD BE WELL EAST OF THE FCST BY EARLY TUESDAY EVENING.
WINDS SHOULD DROP OFF QUICKLY AROUND SUNSET AS PACIFIC HIGH PRESSURE
BUILDS ACROSS THE CENTRAL PLAINS. VERY QUICKLY...A SHOT OF ARCTIC AIR
DROPS SOUTH THROUGH THE WESTERN HIGH PLAINS ON WEDNESDAY AND
THURSDAY. LOW PRESSURE DEVELOPING ACROSS SRN CANADA FRIDAY SHOULD
PRODUCE SOUTHWEST WINDS AND WARMER TEMPERATURES. ANOTHER PACIFIC COLD
FRONT IS FCST TO MOVE THROUGH FRIDAY WITH SLIGHTLY COOLER WEATHER
SATURDAY.
&&
.AVIATION...
VISUAL FLIGHT RULES WILL CONTINUE ACROSS WESTERN NEBRASKA THROUGH
22/03Z. HIGH CLOUDS AOB 15KFT WILL CONTINUE TO SPREAD EAST INTO THE
EVENING WHILE LOWER CLOUDS TO THE EAST ARE A CONCERN. A SPREAD
DEVELOPED BETWEEN THE 12Z MODELS AS TO HOW FAR WEST THE STRATUS OVER
SOUTH CENTRAL AND SOUTHEAST NEB WILL EXPAND. THE RUC AND NOW 18Z NAM
MODELS POINT TO HIGHER BOUNDARY LAYER MOISTURE AVAILABLE THIS
EVENING AND POSSIBLY IMPACTING THE KLBF TERMINAL. FURTHER NORTH THE
COLD FRONT PUSHES EAST SUFFICIENTLY THAT KEEPS LOW CEILINGS OUT FOR
VISUAL FLIGHT RULES THROUGH 18Z SUNDAY. TODAY AT 20Z THE SURFACE
ANALYSIS SHOWED THE COLD FRONT INTO CENTRAL DAKOTAS EXTENDING
SOUTHWEST INTO NORTHEAST WYOMING. THIS EVENING THE SURFACE RIDGE
THAT EXTENDS WEST ACROSS CENTRAL NEB ATTM WEAKENS WITH THE COLD
FRONT MOVING EAST INTO WESTERN NEB. DURING THAT TIME FRAME THE
RUC/NAM SOLUTIONS INCREASE LOW LEVEL MOISTURE WEST WITH THE
POTENTIAL FOR LOW CEILINGS TO DEVELOP WESTWARD AND POSSIBLY
IMPACTING THE KLBF TERMINAL THROUGH 12Z SUNDAY. CURRENT TAFS FOLLOW
THE 12Z NAM SOLUTION THAT WOULD MOVE THE FRONT EAST THAT LIMITED THE
WESTWARD EXTEND TO THE STRATUS TONIGHT. THE 12Z NAM WAS FASTER BUT
GIVEN THE AGREEMENT IN SHORT TERM MODELS CEILINGS WILL NEED TO BE
MONITORED WITH THE POTENTIAL FOR AN UPDATE THIS EVENING FOR THE KLBF
TERMINAL BASED ON THE ADVECTION OF STRATUS INTO THE SOUTHWEST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
CDC/TLK
000
FXUS63 KGID 211720
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1120 AM CST SAT NOV 21 2009
.AVIATION...18Z KGRI TAF. LOW CLOUDS HAVE SPREAD INTO SOUTHERN
NEBRASKA ON THE RETURN OF SOUTHERLY SURFACE FLOW. WITH DEWPOINTS
INTO THE MIDDLE TO UPPER 40S TO THE SOUTH...DO NOT SEE CONDITIONS
CHANGING MUCH THIS AFTERNOON. DO EXPECT A BRIEF PERIOD AFTER SUNSET
OF THE CLOUDS TO BREAK...BUT CONTINUED SOUTHERLY FLOW TONIGHT WILL
RETURN THE LOW CIGS. DO EXPECT SOME FOG AND SOME LIGHT DRIZZLE
AROUND SUNRISE SUNDAY WITH CIGS AOB OVC010 AND VSBYS AOB 1SM.
CONDITIONS WILL SLOWLY IMPROVE DURING THE DAY SUNDAY...BUT WILL
REMAIN IFR FOR THE REMAINDER OF THE FORECAST PERIOD. -KISNER
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
000
FXUS63 KGID 211114
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
514 AM CST SAT NOV 21 2009
.AVIATION...12Z TAF. EARLY MORNING SATELLITE IMAGERY SHOWS A LARGE
AREA OF STRATUS MOVING NORTH ACROSS CENTRAL AND EASTERN KANSAS.
AT ITS CURRENT PACE...IT SHOULD ARRIVE AT KGRI AROUND 15Z. THERE
IS STILL SOME DISAGREEMENT AMONG THE VARIOUS SHORT TERM FORECAST
MODELS ON HOW LONG THE STRATUS WILL THEN PERSIST AT KGRI. WILL
STILL SIDE WITH A MORE OPTIMISTIC APPROACH WHICH MOVES THE THICKER
CLOUDS TO THE EAST OF KGRI LATER THIS AFTERNOON AND RETURNS THE
TERMINAL TO VFR CONDITIONS. WINDS WILL ALSO BE ON THE INCREASE
TODAY...AND EXPECT THEM TO BECOME GUSTY FROM THE SOUTH BY 18Z.
MOISTURE WILL CONTINUE TO SURGE INTO THE REGION AHEAD OF A COLD
FRONT TONIGHT. THIS WILL BRING A FAIRLY GOOD CHANCE OF IFR
CONDITIONS TO KGRI TOWARDS LATE EVENING. WILL SHOW AN IFR CEILING
DEVELOPING AROUND 04Z...WITH LIFR CONDITIONS BECOMING POSSIBLE
EARLY SUNDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 309 AM CST SAT NOV 21 2009/
DISCUSSION...ALOFT...SHORTWAVE RIDGING WAS IN PLACE ACROSS THE
CENTRAL PLAINS WHILE TO THE WEST...A TROUGH STRETCHED FROM BRITISH
COLUMBIA SOUTH THROUGH THE ROCKIES. THE SHORTWAVE RIDGE AXIS WILL
SHIFT EASTWARD TODAY AS THE WESTERN TROUGH ADVANCES TO THE EAST. AT
THE SURFACE THE ASSOCIATED TROUGH WILL DEEPEN IN THE LEE OF THE
ROCKIES AND THE GRADIENT WILL TIGHTEN...RESULTING IN INCREASING
SOUTHERLY WINDS TO THE BREEZY CATEGORY AT TIMES. CLOUD COVER FOR
TODAY IS CHALLENGING AS AN AREA OF STRATUS CURRENTLY LOCATED
ACROSS CENTRAL/SOUTHEAST KANSAS WILL WORK ITS WAY NORTHWARD DURING
THE DAY. OUR SOUTHERN CWA MAY SEE SOME FOG DEVELOPMENT THIS
MORNING AND WILL CONTINUE TO MONITOR TRENDS OF THIS IN THE NEXT
FEW HOURS. WHETHER OR NOT THE LOW CLOUDS MIX OUT TODAY REMAINS IN
QUESTION AS THE NAM SUGGESTS THIS IS MORE PROBABLE THAN THE GFS
WHICH MAINTAINS CLOUD COVER ACROSS THE MAJORITY OF OUR CWA FOR
MUCH OF THE DAY. CONFIDENCE IS NOT HIGH IN THIS REGARD AND DID OPT
FOR A CONSERVATIVE APPROACH WITH SOME CLOUDS AROUND.
TONIGHT...THE TROUGH AXIS BEGINS TO PUSH EAST OF THE ROCKIES AND
SOUTHWESTERLY FLOW ALOFT IS ENHANCED ACROSS THE PLAINS. MOISTURE
CONTINUES TO ADVECT NORTH AHEAD OF THE SURFACE BOUNDARY WHICH
APPROACHES OUR WESTERN CWA SUNDAY MORNING. STRATUS IS EXPECTED TO
SETTLE IN ACROSS OUR CWA AHEAD OF THE SURFACE BOUNDARY. WINDS WILL
BE LIGHT ALONG THE BOUNDARY AXIS AND THE NAM IS THE MOST
AGGRESSIVE IN SUGGESTING THE POTENTIAL FOR THE DEVELOPMENT OF
DENSE FOG VS THE GFS. SREF PROBABILITIES LEND CREDENCE TO THE NAM
AND HAVE INCLUDED SOME LOW VISIBILITY POTENTIAL IN THE GRIDS BUT
STOPPED SHORT OF ADVISORY CRITERIA FOR NOW. WEAK LIFT OVER THE
SHALLOW LOW LEVEL MOISTURE MAY LEAD TO THE DEVELOPMENT OF SOME
DRIZZLE.
THE TROUGH/WAVE MOVES THROUGH ON SUNDAY AND THIS SYSTEM MAY GENERATE
SOME LIGHT PCPN IN THE AFTN IN OUR EAST WHERE BETTER MOISTURE IS
PRESENT. THE WAVE DOES NOT EFFECTIVELY SCOUR THE LOW LEVEL MOISTURE
AND HAVE SOME CONCERNS THAT THE STRATUS WILL REMAIN SUNDAY NIGHT AND
FOG MAY DEVELOP AGAIN. HAVE INTRODUCED SOME PATCHY FOG FOR NOW AS
A START.
THE FORECAST TURNS MORE INTERESTING ON MONDAY AS ANOTHER TROUGH DIGS
SOUTH FROM THE NORTHERN ROCKIES AND IS FORECAST TO CLOSE OFF ACROSS
THE PLAINS ON MONDAY. MODELS HAVE VARIED ON WHERE THE LOW WILL
CLOSE OFF/TRACK WITH THE GFS REMAINING FARTHER NORTH THAN THE
NAM/ECMWF/GEM. HAVE TRENDED TOWARD THE SOUTHERN SOLUTION FOR NOW
WITH PCPN CHCS INCREASING ON MONDAY AHEAD OF THE SYSTEM AND
CONTINUING MONDAY NIGHT/TUESDAY IN THE DEFORMATION/WRAPAROUND. THE
PREDOMINATE PCPN TYPE SHOULD BE RAIN INITIALLY BUT A R/S MIX OR A
CHANGEOVER TO SNOW W/E ON THE BACK SIDE OF THE SYSTEM IS POSSIBLE
MONDAY NIGHT INTO TUESDAY. IN ADDITION THE PCPN POTENTIAL...VERY
STRONG WINDS ON THE BACK SIDE OF THE SYSTEM WILL BUFFET OUR REGION
MONDAY NIGHT/TUESDAY WITH WIND GUSTS OVER 40 MPH POSSIBLE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
000
FXUS63 KOAX 210915
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
315 AM CST SAT NOV 21 2009
.DISCUSSION...
TYPICAL FOR NOVEMBER THE WEATHER ACROSS THE CWA WILL BE VARIABLE AND
CHANGEABLE THROUGH MIDWEEK AS IT IS BECOMING MORE LIKELY A CLOSED
WEATHER SYSTEM WILL DEVELOP AND THEN SLOWLY TRACK ACROSS CENTRAL
PLAINS BY MON NGT THRU TUE NGT PDS. BEFORE THEN FOG...LOW CLOUDS
AND POSSIBLE DRIZZLE OR LIGHT/SMALL MEASURABLE PCPN CHCS WILL HAVE
TO BE DEALT WITH.
SHORTER TERM...TODAY THROUGH SUNDAY NIGHT. MOISTURE WAS NEVER
REALLY SCOURED OUT OF FAR SERN ZONES YDA WHICH ALLOWED DENSE FOG
FORMATION RATHER EARLY LAST EVENING. ALTHOUGH SFC WINDS SHOULD
INCREASE A BIT THIS MORNING...THEIR INCREASE WL PRBLY NOT BE SOON
ENOUGH TO IMPROVE CONDITIONS BEFORE 15Z. THUS THE DENSE FOG
ADVSRY WAS KEPT IN PLACE. ALTHOUGH PATCHY FOG MENTION THIS MORNING
WAS EXPANDED A BIT NW...FELT WIDESPREAD POOREST VSBYS WOULD BE
CONFINED TO ADVISORY REGION. OTHERWISE EARLY MORNING FOG CURVE
STLT IMAGERY SHOWED LOW CLOUDS WORKING SLOWLY NWD THRU KS AND
THESE WILL LIKELY IMPACT MUCH OF THE CWA LATER TODAY INTO SUNDAY
AND PROBABLY MONDAY AS WELL. SO EVEN THOUGH 850 MB TEMPS ARE
FORECAST TO REMAIN FAIRLY SIMILAR THROUGH MONDAY...MAX TEMPS COULD
BE MILDEST TDA GIVEN THAT THE MOST SUNSHINE IS EXPECTED. MADE LTL
CHANGES TO GOING FORECAST. WATER VAPOR IMAGERY SHOWED TROUGH
MOVING INTO WRN UT WAS SPREADING HIGH CLOUDS AS FAR EAST AS NRN
PLAINS AS OF 08Z AND THIS THROUGH WILL MOVE ACROSS THE CWA LATER
TODAY INTO SUNDAY. HOWEVER...WITH MUCH STRONGER ENERGY FORECAST TO
DIG DOWN BEHIND IT LATE SUNDAY... LEAD WAVE COULD HAVE A TENDENCY
TO FRAGMENT OR DAMPEN IT AS IT CROSSES FCST AREA. THE FIRST UPPER
TROUGH COULD PUSH A SFC TROUGH TOWARD OR INTO NWRN ZONES SUN AFTN
PER NAM/GFS...BUT IF IT DOES IT SHOULD WASH OUT OR BECOME
REESTABLISHED FARTHER W ON MONDAY AS THE MAIN SYSTEM APPROACHES.
WITH LOW LVL MOISTURE SPREADING NWD KEPT IN DRIZZLE LATE TNGT AND
SMALL PCPN CHCS SUN AND MON ALONG WITH GENERALLY MOCLDY SKIES. DID
NOTE THAT THERE WAS DRIZZLE THIS MORNING FM OK INTO NRN TX IN THE
STRATUS/STRATOCU AND AS MOISTURE DEEPENS TONIGHT...LIFT FROM
APPROACHING TROUGH COULD GENERATE SOME HERE AS WELL.
BEGINNING LATE MONDAY ATTENTION TURNS TO THIS TRAILING DEVELOPING
STORM SYSTEM. GENERALLY KEPT FORECAST MORE CLOSELY TIED TO THE ECMWF
WHICH HAS BEEN FARTHER SW/SLOWER AND MORE CONSISTENT THAN THE GFS
AND WAS SHOWN SOME SUPPORT FM 00Z/06Z NAM. SINCE THE 00Z ECMWF HAS
PROVIDED NO BIG SURPRISES AND HAS GENERALLY MAINTAINED ITS
CONSISTENCY...INCREASED POPS A BIT MORE IN THE MON THRU TUE NGT
PD AS CONFIDENCE IN ITS SOLUTION HAS INCREASED SOME. ALTHOUGH
ECMWF ALSO CONTINUED TO KEEP THE SYSTEM FAIRLY WARM THRU TUE W/850
MB TEMPS ABOVE 0 DEG C TILL 00Z WED...LEFT IN RAIN/SNOW MENTION
MON NGT/TUE WRN ZONES GIVEN TIME OF YEAR AND THE FACT THAT THE
CANADIAN/NAM WERE COLDER AND SUPPORTED SNOW OVER EVEN A LARGER
PART OF THE CWA. SYSTEM DEFINITELY BEARS WATCHING... ESPECIALLY
SINCE IT WILL BE AFFECTING THE BEGINNING OF THE HOLIDAY TRAVEL
WEEK AND WILL BE PACKING STRONG WINDS.
STILL LOOKS LIKE A LATE WEEK WARMING TREND SETTING UP FOLLOWING
THIS SYSTEM...IF WE CAN AVOID SIGNIFICANT SNOW ANYWAY.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
VFR CONDITIONS ARE EXPECTED THROUGH 18Z AS HIGH PRESSURE MOVES
SLOWLY EAST TODAY WITH SURFACE GRADIENT INCREASING ACROSS THE AREA.
SOME MVFR CIGS DEVELOPING 18Z-00Z AS MOISTURE OVER THE SOUTHERN PLAINS
ADVECTS NORTH WITH THE INCREASING SOUTH FLOW. MVFR CIGS LIKELY AFTER
00Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR NEZ068-
090>093.
IA...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR IAZ080-090-
091.
&&
$$
CHERMOK/FOBERT
000
FXUS63 KGID 210909
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
309 AM CST SAT NOV 21 2009
.DISCUSSION...ALOFT...SHORTWAVE RIDGING WAS IN PLACE ACROSS THE
CENTRAL PLAINS WHILE TO THE WEST...A TROUGH STRETCHED FROM BRITISH
COLUMBIA SOUTH THROUGH THE ROCKIES. THE SHORTWAVE RIDGE AXIS WILL
SHIFT EASTWARD TODAY AS THE WESTERN TROUGH ADVANCES TO THE EAST. AT
THE SURFACE THE ASSOCIATED TROUGH WILL DEEPEN IN THE LEE OF THE
ROCKIES AND THE GRADIENT WILL TIGHTEN...RESULTING IN INCREASING
SOUTHERLY WINDS TO THE BREEZY CATEGORY AT TIMES. CLOUD COVER FOR
TODAY IS CHALLENGING AS AN AREA OF STRATUS CURRENTLY LOCATED
ACROSS CENTRAL/SOUTHEAST KANSAS WILL WORK ITS WAY NORTHWARD DURING
THE DAY. OUR SOUTHERN CWA MAY SEE SOME FOG DEVELOPMENT THIS
MORNING AND WILL CONTINUE TO MONITOR TRENDS OF THIS IN THE NEXT
FEW HOURS. WHETHER OR NOT THE LOW CLOUDS MIX OUT TODAY REMAINS IN
QUESTION AS THE NAM SUGGESTS THIS IS MORE PROBABLE THAN THE GFS
WHICH MAINTAINS CLOUD COVER ACROSS THE MAJORITY OF OUR CWA FOR
MUCH OF THE DAY. CONFIDENCE IS NOT HIGH IN THIS REGARD AND DID OPT
FOR A CONSERVATIVE APPROACH WITH SOME CLOUDS AROUND.
TONIGHT...THE TROUGH AXIS BEGINS TO PUSH EAST OF THE ROCKIES AND
SOUTHWESTERLY FLOW ALOFT IS ENHANCED ACROSS THE PLAINS. MOISTURE
CONTINUES TO ADVECT NORTH AHEAD OF THE SURFACE BOUNDARY WHICH
APPROACHES OUR WESTERN CWA SUNDAY MORNING. STRATUS IS EXPECTED TO
SETTLE IN ACROSS OUR CWA AHEAD OF THE SURFACE BOUNDARY. WINDS WILL
BE LIGHT ALONG THE BOUNDARY AXIS AND THE NAM IS THE MOST
AGGRESSIVE IN SUGGESTING THE POTENTIAL FOR THE DEVELOPMENT OF
DENSE FOG VS THE GFS. SREF PROBABILITIES LEND CREDENCE TO THE NAM
AND HAVE INCLUDED SOME LOW VISIBILITY POTENTIAL IN THE GRIDS BUT
STOPPED SHORT OF ADVISORY CRITERIA FOR NOW. WEAK LIFT OVER THE
SHALLOW LOW LEVEL MOISTURE MAY LEAD TO THE DEVELOPMENT OF SOME
DRIZZLE.
THE TROUGH/WAVE MOVES THROUGH ON SUNDAY AND THIS SYSTEM MAY GENERATE
SOME LIGHT PCPN IN THE AFTN IN OUR EAST WHERE BETTER MOISTURE IS
PRESENT. THE WAVE DOES NOT EFFECTIVELY SCOUR THE LOW LEVEL MOISTURE
AND HAVE SOME CONCERNS THAT THE STRATUS WILL REMAIN SUNDAY NIGHT AND
FOG MAY DEVELOP AGAIN. HAVE INTRODUCED SOME PATCHY FOG FOR NOW AS
A START.
THE FORECAST TURNS MORE INTERESTING ON MONDAY AS ANOTHER TROUGH DIGS
SOUTH FROM THE NORTHERN ROCKIES AND IS FORECAST TO CLOSE OFF ACROSS
THE PLAINS ON MONDAY. MODELS HAVE VARIED ON WHERE THE LOW WILL
CLOSE OFF/TRACK WITH THE GFS REMAINING FARTHER NORTH THAN THE
NAM/ECMWF/GEM. HAVE TRENDED TOWARD THE SOUTHERN SOLUTION FOR NOW
WITH PCPN CHCS INCREASING ON MONDAY AHEAD OF THE SYSTEM AND
CONTINUING MONDAY NIGHT/TUESDAY IN THE DEFORMATION/WRAPAROUND. THE
PREDOMINATE PCPN TYPE SHOULD BE RAIN INITIALLY BUT A R/S MIX OR A
CHANGEOVER TO SNOW W/E ON THE BACK SIDE OF THE SYSTEM IS POSSIBLE
MONDAY NIGHT INTO TUESDAY. IN ADDITION THE PCPN POTENTIAL...VERY
STRONG WINDS ON THE BACK SIDE OF THE SYSTEM WILL BUFFET OUR REGION
MONDAY NIGHT/TUESDAY WITH WIND GUSTS OVER 40 MPH POSSIBLE.
&&
.AVIATION...06Z TAF. MAIN CONCERN FOR THE TAF PERIOD IS THE
POTENTIAL FOR THE ARRIVAL OF STRATUS JUST AFTER DAYBREAK ON
SATURDAY. THE LEADING EDGE OF THE STRATUS CLOUDS IS LOCATED ACROSS
SOUTH CENTRAL KANSAS ATTM AND WITH INCREASING SOUTHERLY FLOW
OVERNIGHT AND SATURDAY...THE LOW CLOUDS WILL ADVECT NORTHWARD. FOR
NOW HAVE KEPT CEILINGS IN THE MVFR RANGE FOR A FEW HOURS AND THEN
SCATTERED THE CLOUDS IN THE AFTERNOON. IN A TIGHTENING SURFACE
GRADIENT...SOUTHERLY WINDS WILL INCREASE ON SATURDAY WITH GUSTS
AROUND 25KTS POSSIBLE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
000
FXUS63 KLBF 210906
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
306 AM CST SAT NOV 21 2009
.SYNOPSIS...
LONG WAVE TROF CRASHING ONSHORE ACROSS THE WEST COAST WITH WELL
DEFINED WAA ZONE OUT AHEAD OF IT AND DEVELOPING MID AND UPPER LEVEL
CLOUDS OVER THE CENTRAL ROCKIES INTO THE NRN PLAINS. LOWERING
PRESSURES IN RESPONSE TO ELVOLVING SWRLY FLOW FURTHER WEST ALLOWING
DECENT LLJ FOR THE TIME OF YEAR AND ASSOC MIXING ACROSS THE SANDHILLS
KEEPING TEMPS UP THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
BRIEF TRANSITORY RIDGE EXISTS TODAY BEING REPLACED BY DEVELOPING
LEE TROF AS LEAD SHORT WAVE PROGRESSES QUICKLY ACROSS SRN CANADA.
SWRLY FLOW AS UPPER HIGH EXISTS ALLOWS EML TO OVERSPREAD THE AREA
THIS MORNING AND ALTHOUGH MIXING MAY BE LIMITED INITIALLY DUE TO
CLOUD COVER...AREAS EAST OF A LINE FROM OGA TO VTN WILL BENEFIT
FROM MECHANICAL MIXING TO ALLOW TEMPS TO REACH U50S TO POSSIBLY
L60S. AS SHORT WAVE CONTINUES ACROSS SRN CANADA TONIGHT...WEAK
FRONT WILL PROGRESS THROUGH THE CWA OVERNIGHT. INITIALLY...MID
LEVEL FGEN WILL ALLOW A COUPLED CIRCULATION TO KEEP FRONT MOVING
EWD...BUT AS UPPER SUPPORT OUTRUNS SFC FEATURE FRONTOLYSIS AND
EVENTUALLY LOW LEVEL FRONTAL FRACTURE OCCURS JUST SE OF CWA. DRY
MID AND LOWER LAYERS WILL INHIBIT PREICP REACHING THE GROUND AND
HAVE LEFT FCST DRY SAT NIGHT AND EARLY SUNDAY. LOW LEVEL MOISTURE
POISED TO RETURN NWD SUNDAY MORNING...BUT SHOULD BE DEPLACED E OF
ADVANCING FRONT AND THEREFORE E OF CWA AND HAVE REMOVED MENTION OF
FOG IN ZONES. THIS WILL HAVE TO BE MONITORED IF FRONT WEAKENS
EARLY.
NEXT...MORE IMPRESSIVE...SHORT WAVE BEGINS TO DIG ACROSS THE CENTRAL
ROCKIES SUNDAY. LEE TROF IN ADVANCE OF THIS WILL ALLOW WINDS TO
SHIFT TO SRLY AGAIN AND WILL BEGIN THE TRANSPORT OF MOISTURE NWWD.
SUNDAY WILL BE COOLER BEHIND THE FRONT. THE MOISTURE WILL HAVE A
HARD TIME INITIALLY MOVING TOO FAR W AND DRY MID LEVELS WILL INHIBIT
ANY PRECIP DEVELOPMENT THROUGH SUNDAY NIGHT. LOW LEVELS WILL
SATURATE SUNDAY NIGHT AND BR AND STRATUS WILL LIKELY BE THE RESULT.
LOW TEMPS HAVE BEEN ADJUSTED SLIGHTLY UPWARD TO ACCOUNT FOR INCREASE
OF LL MOISTURE AND CLOUD COVER. THOUGH DECENT SUNSHINE FOR
SUNDAY...SERLY WINDS WILL BE RECYCLING COOLER POST FRONTAL AIRMASS.
SIGNIFICANT DIFFS IN MODELS BY EARLY MONDAY. 00Z 21 NOV RUN OF THE
ECMWF WOULD HAVE THE MOST IMPACT FOR THE CWA...BUT THIS MODEL HAS
DRIFTED NWD WITH THE UPPER LOW COMPARED TO ITS 12Z 20 NOV
COUNTERPART. AT THE SAME TIME...THE GFS HAS TRENDED SLIGHTLY SLOWER
AND SWD...BUT WOULD LEAVE WRN CWA MAINLY DRY AND PRECIP FOR NERN CWA
WOULD COME DURING THE DAY MONDAY. EVEN IF THE ECMWF VERIFIES...A LOOK AT
MOISTURE TRANSPORT VECTORS ON ISENTROPIC SFCS WOULD SUGGEST WCB
WOULD NOT HAVE A CHANCE TO WORK INTO THE SYSTEM UNTIL IT REACHES ERN
NEBR. THERE DOES APPEAR TO BE A SMALL WINDOW OF OPPORTUNITY THOUGH
FOR WCB/CCB INTERACTION AND ASSOCIATED FGEN IN FAVORED NW QUAD OF
DEVELOPING UPPER LOW...OVER NERN CWA BEGINNING MONDAY NIGHT AND
CONTINUING TUESDAY. IN ADDITION TO AND AS A RESULT OF TIMING DIFFS BTWN
MODELS...PRECIP TYPE IS AT ISSUE AS WELL. WARM LOW LEVELS AS
SUGGESTED BY BUFR SOUNDINGS WOULD INDICATE LITTLE CHANCE FOR
SIGNIFICANT ACCUMULATING SNOWS UNTIL TUES...AND ONLY IF ECMWF
VERIFIES. GFS DOES BRING MORE COLD AIR SWD THAN ECMWF ON MONDAY
AND THEREFORE SNOWFALL WOULD START SOONER...BUT WOULD END SOONER
AS WELL. TOO MANY DIFFS AT THIS POINT TO WORK OUT DETAILS UNFORTUNATELY.
.LONG TERM...(WEDNESDAY THROUGH FRIDAY)
EARLIER DISCUSSED DIFFS MAGNIFY LATER IN THE WEEK LEADING TO A WIDE
ENVELOPE OF PLAUSIBLE SOLUTIONS. HOWEVER END RESULT BY THE END OF
THE WEEK WOULD BE TO TREND TWD INCREASING HEIGHTS ALOFT AND A DRY
FCST. NO CHANGES MADE BEYOND MON/TUE TIME FRAME FOR NOW...BUT EARLY
INDICATIONS FOR THANKSGIVING ARE MAINLY DRY...THOUGH TRENDING MORE
ACTIVE TWD THE WEEKEND.
&&
.AVIATION...
A SURFACE TROUGH OF LOW PRESSURE WILL DEEPEN AND TRACK
EAST TODAY ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. STRONG
SOUTHERLY WINDS OF 15 TO 25 KTS WILL DEVELOP EAST OF THIS
FEATURE...WHILE WESTERLY WINDS OF 10 TO 20 KTS WILL BE COMMON WEST
OF THE SURFACE TROUGH. WINDS ARE EXPECTED TO DIMINISH THIS EVENING WITH
WESTERLY WINDS OF 5 TO 15 KTS EXPECTED. MID TO HIGH LEVEL CLOUDINESS
WILL BE ON THE INCREASE THIS AFTERNOON AND TONIGHT EAST OF AN
APPROACHING UPPER LEVEL TROUGH OF LOW PRESSURE. CEILINGS AOA 15000
FEET AGL ARE LIKELY AT BOTH THE KVTN AND KLBF TERMINALS THROUGH 12Z
SUNDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...JWS
AVIATION...CLB
000
FXUS63 KGID 210514
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1114 PM CST FRI NOV 20 2009
.AVIATION...06Z TAF. MAIN CONCERN FOR THE TAF PERIOD IS THE
POTENTIAL FOR THE ARRIVAL OF STRATUS JUST AFTER DAYBREAK ON
SATURDAY. THE LEADING EDGE OF THE STRATUS CLOUDS IS LOCATED ACROSS
SOUTH CENTRAL KANSAS ATTM AND WITH INCREASING SOUTHERLY FLOW
OVERNIGHT AND SATURDAY...THE LOW CLOUDS WILL ADVECT NORTHWARD. FOR
NOW HAVE KEPT CEILINGS IN THE MVFR RANGE FOR A FEW HOURS AND THEN
SCATTERED THE CLOUDS IN THE AFTERNOON. IN A TIGHTENING SURFACE
GRADIENT...SOUTHERLY WINDS WILL INCREASE ON SATURDAY WITH GUSTS
AROUND 25KTS POSSIBLE.
&&
.PREV DISCUSSION... /ISSUED 1004 PM CST FRI NOV 20 2009/
UPDATE...MAIN UPDATE THIS EVENING WAS TO INSERT MENTION OF PATCHY
FOG INTO PORTIONS OF NORTH CENTRAL KS MAINLY EAST OF HIGHWAY 281.
MOST FAVORABLE CONDITIONS FOR FOG DEVELOPMENT SHOULD REMAIN JUST
TO THE SOUTH/EAST OF THE CWA WHERE WEAK MOISTURE ADVECTION IS
ENHANCED...BUT FELT THAT PATCHY MENTION WAS STILL WARRANTED AS
LIGHT SOUTHERLY RETURN FLOW AROUND THE RIDGE AXIS SHOULD REMAIN
WEAKEST HERE AS WELL. OTHERWISE MADE ONLY SOME MINOR TWEAKS TO
TEMPS/DEWPOINTS/SKY COVER.
PREV DISCUSSION... /ISSUED 338 PM CST FRI NOV 20 2009/
SHORT TERM...TONIGHT THROUGH 12Z SUNDAY. NOT MUCH IN THE WAY OF
WEATHER IN THIS PERIOD. SURFACE RIDGE IS MOVING ACROSS THE AREA THIS
AFTERNOON WITH SOUTHERLY FLOW RETURNING. SURFACE TROUGH WILL DEVELOP
AND STRENGTHEN ACROSS THE WESTERN HIGH PLAINS TONIGHT AND
SATURDAY. THIS WILL INCREASE THE PRESSURE GRADIENT AND SO WILL THE
WINDS. EXPECT A BREEZY DAY ON SATURDAY WITH SOUTH WINDS OF 15 TO
25 MPH. LITTLE IN THE WAY OF MOISTURE IN PLACE NOW SO CLEAR SKIES
WILL PREVAIL INTO SATURDAY. AS SOUTHERLY FLOW CONTINUES INTO
SATURDAY NIGHT...LOW LEVEL MOISTURE WILL INCREASE AND WILL BRING
LOW CLOUDS AND SOME PATCHY FOG/DRIZZLE TO THE AREA BY SUNRISE
SUNDAY.
LONG TERM...12Z SUNDAY THROUGH FRIDAY. THE MAIN FOCUS OF THIS
FORECAST IS ON EARLY NEXT WEEK SYSTEM...WHICH LOOKS TO BE A PRETTY
SIGNIFICANT WEATHER MAKER FOR THE AREA DURING THE MONDAY/TUESDAY
TIMEFRAME.
STARTING OUT SUNDAY MORNING...WILL BE DEALING WITH LOW CLOUDS...FOG
AND DRIZZLE ACROSS THE CWA. A WEAK SURFACE FRONT WILL BE BISECTING
THE CWA FROM NORTH TO SOUTH...WITH SOUTHERLY LOW-LEVEL FLOW AHEAD OF
THE BOUNDARY KEEPING RICH LOW-LEVEL MOISTURE IN PLACE. SOUNDINGS
CONTINUE TO SUPPORT FOG AND DRIZZLE...WITH SATURATED LOW LEVELS
BENEATH A DRY PROFILE ALOFT...AND HENCE PREFER THE INHERITED DRIZZLE
MENTION VERSUS SHOWERS. FORCING AHEAD OF AN OPEN UPPER WAVE ACTING
ON THE MOIST LOW LEVELS SHOULD BE SUFFICIENT TO SQUEEZE OUT SOME
DRIZZLE ACROSS THE EASTERN HALF OR SO OF THE CWA SUNDAY
MORNING...POSSIBLY LINGERING INTO THE AFTERNOON HOURS IN THE FAR
SOUTHEAST. TEMPERATURES ARE TRICKY ON SUNDAY. THE SURFACE BOUNDARY
WASHES OUT AND A FAIRLY WARM AIRMASS IS IN PLACE /H85 TEMPS
GENERALLY +3-5C/...BUT LOW CLOUDS WILL BE SLOW TO CLEAR ESPECIALLY
IN THE EAST. WILL AIM HIGHS IN THE MID 40S TO LOWER 50S...BUT THIS
COULD EASILY TILT EITHER WAY BASED ON CLEARING TRENDS.
SHOULD CATCH A BREAK BETWEEN SYSTEMS SUNDAY NIGHT...BEFORE A MUCH
STRONGER UPPER LOW BEGINS TO IMPACT THE AREA ON MONDAY. MODELS
/EXCLUDING THE GFS/ HAVE BEGUN TO COME INTO MUCH BETTER AGREEMENT ON
THIS EARLY WEEK SYSTEM...WITH THE TREND TOWARD A MUCH
DEEPER/STRONGER/SLOWER AND MORE IMPACTFUL SYSTEM FOR THE AREA. THE
LAST COUPLE RUNS OF BOTH THE ECMWF AND CMC GEM HAVE SHOWN THIS
SOLUTION...AND THE NAM THROUGH 84 HOURS IS ALSO CARVING OUT A DEEPER
LOW. THE GFS REMAINS THE OUTLIER IN KEEPING A MUCH MORE NORTHERN AND
PROGRESSIVE TRACK THROUGH THE PLAINS. HAVE TRENDED THE FORECAST
TOWARD THE ECMWF/GEM SOLUTION WHICH HAS MUCH MORE SUPPORT THAN THE
GFS AT THIS POINT...SEEMS MORE REALISTIC GIVEN THE UPPER JET
ENERGY DIGGING DOWN THE BACKSIDE OF THE SYSTEM...AND IS THE
PREFERRED HPC SOLUTION. FOLLOWING THIS SOLUTION...AN UPPER LOW
WILL DIG THROUGH THE CENTRAL ROCKIES...CLOSING OFF OVER NORTHWEST
KS BY MONDAY EVENING...THEN TRACKING EITHER EAST OR NORTHEAST OVER
NORTHERN KS OR SOUTHERN NE MONDAY NIGHT THROUGH TUESDAY NIGHT
BEFORE PUSHING INTO IA/MO BY WEDNESDAY. HOWEVER...THE EXACT TRACK
IT TAKES ACROSS KS/NE AND THE TIMING OF THE LOW/S MOVEMENT IS
STILL HIGHLY UNCERTAIN AND WILL HAVE A HUGE IMPACT ON THE AREA/S
WEATHER DURING THE MONDAY NIGHT THROUGH TUESDAY NIGHT TIMEFRAME.
FOR EXAMPLE...THE 20/12Z ECMWF SLOWED THE PROGRESSION OF THE
SYSTEM DOWN BY NEARLY 12 HOURS COMPARED TO THE PREVIOUS 20/00Z
RUN...WHICH OBVIOUSLY SLOWS DOWN THE INTRUSION OF COLDER AIR INTO
THE CWA ON THE BACKSIDE AND RESULTANT CHANGEOVER TO SNOW. IT WAS
LOOKING LIKE THIS CHANGEOVER WOULD OCCUR MONDAY NIGHT OVER MOST OF
THE CWA...BUT THE SLOWER 12Z ECMWF WOULD LIKELY DELAY IT UNTIL
TUESDAY FOR MOST IF NOT ALL AREAS. BY THAT TIME HOW MUCH COLD AIR
WILL BE AVAILABLE FOR THE SYSTEM TO WORK WITH COMES INTO QUESTION
SINCE THE SYSTEM IS NO LONGER DEEPENING...THEREBY SQUELCHING THE
DYNAMIC COOLING...AND THE TAP OF COLDER AIR FROM THE NORTH BEGINS
TO GET CUT OFF DUE TO THE CLOSED NATURE OF THE LOW. ON THE OTHER
HAND...THE GEM IS STILL QUITE AGGRESSIVE WITH THE COLD AIR SURGE
MONDAY NIGHT INTO TUESDAY...WHICH WOULD MEAN A SIGNIFICANT SNOW
STORM FOR THE AREA. NEEDLESS TO SAY...A LOT OF UNCERTAINTY LOOMS
WITH THIS SYSTEM. IT DOES LOOK ACTIVE/WET LATE MONDAY INTO
TUESDAY...MAYBE TUESDAY NIGHT...BUT THE DETAILS INCLUDING PRECIP
TYPE AND AMOUNT ARE STILL QUITE UNCERTAIN. MAIN CHANGES TO THE
FORECAST WERE TO INSERT/INCREASE POPS MONDAY THROUGH TUESDAY
NIGHT...COOL DAYTIME TEMPERATURES DURING THIS TIME...AND INTRODUCE
A RAIN/SNOW MIX. WINDS WILL BE PRETTY STRONG ON THE BACKSIDE OF
THE SYSTEM MONDAY NIGHT/TUESDAY...SO DEPENDING ON THE PRECIP PHASE
THIS COULD CAUSE MORE PROBLEMS. WILL HAVE TO KEEP A CLOSE EYE ON
THIS SYSTEM THROUGH THE WEEKEND...WITH MANY ADJUSTMENTS TO THE
FORECAST LIKELY YET TO COME.
FORTUNATELY...THIS SYSTEM PUSHES EAST PRIOR TO THE THANKSGIVING DAY
HOLIDAY AND THE BIG TRAVEL DAY ON WEDNESDAY. A NORTH/NORTHWEST FLOW
WILL RETURN ON WEDNESDAY IN BETWEEN THE DEPARTING SYSTEM AND UPPER
RIDGING OVER THE WESTERN CONUS. DRY CONDITIONS THEN PREVAIL
WEDNESDAY THROUGH FRIDAY AS THE WESTERN UPPER RIDGE GRADUALLY
PROPAGATES EAST. MODELS HAVE BEEN BACK AND FORTH WITH A POSSIBLE
TRAILING WAVE WEDNESDAY...WHICH COULD BRING IN A REINFORCING SHOT OF
COLDER AIR...DELAYING THE WARM-UP...BUT DOESN/T LOOK TO BRING ANY
PRECIP WITH IT. WILL SEE MODERATING TEMPERATURES WEDNESDAY THROUGH
FRIDAY AS HIGHS CLIMB BACK INTO THE 50S BY WEEK/S END...MAKING FOR A
NICE HOLIDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
000
FXUS63 KGID 210404
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1004 PM CST FRI NOV 20 2009
.UPDATE...MAIN UPDATE THIS EVENING WAS TO INSERT MENTION OF PATCHY
FOG INTO PORTIONS OF NORTH CENTRAL KS MAINLY EAST OF HIGHWAY 281.
MOST FAVORABLE CONDITIONS FOR FOG DEVELOPMENT SHOULD REMAIN JUST
TO THE SOUTH/EAST OF THE CWA WHERE WEAK MOISTURE ADVECTION IS
ENHANCED...BUT FELT THAT PATCHY MENTION WAS STILL WARRANTED AS
LIGHT SOUTHERLY RETURN FLOW AROUND THE RIDGE AXIS SHOULD REMAIN
WEAKEST HERE AS WELL. OTHERWISE MADE ONLY SOME MINOR TWEAKS TO
TEMPS/DEWPOINTS/SKY COVER.
&&
.PREV DISCUSSION... /ISSUED 541 PM CST FRI NOV 20 2009/
AVIATION...00Z KGRI TAF. SOUTH WINDS WILL CONTINUE THROUGH THE
TAF VALID PERIOD AND INCREASE DURING THE DAY TOMORROW. THESE WINDS
WILL BEGIN TO PUMP MOISTURE NORTHWARD...WHICH COULD RESULT IN A
LOW STRATUS DECK BEGINNING SHORTLY AFTER SUNRISE TOMORROW. THERE
IS STILL SOME UNCERTAINTY AS TO HOW FAR NORTH THE STRATUS DECK WILL
MAKE IT...AND WHETHER OR NOT IT WILL REACH KGRI. HOWEVER...THE
POSSIBILITY OF THESE IFR CEILINGS SEEMS HIGH ENOUGH TO WARRANT
INCLUSION IN THE TAF AND LOW CLOUDS COULD PERSIST THROUGH EARLY
AFTERNOON.
PREV DISCUSSION... /ISSUED 338 PM CST FRI NOV 20 2009/
SHORT TERM...TONIGHT THROUGH 12Z SUNDAY. NOT MUCH IN THE WAY OF
WEATHER IN THIS PERIOD. SURFACE RIDGE IS MOVING ACROSS THE AREA THIS
AFTERNOON WITH SOUTHERLY FLOW RETURNING. SURFACE TROUGH WILL DEVELOP
AND STRENGTHEN ACROSS THE WESTERN HIGH PLAINS TONIGHT AND
SATURDAY. THIS WILL INCREASE THE PRESSURE GRADIENT AND SO WILL THE
WINDS. EXPECT A BREEZY DAY ON SATURDAY WITH SOUTH WINDS OF 15 TO
25 MPH. LITTLE IN THE WAY OF MOISTURE IN PLACE NOW SO CLEAR SKIES
WILL PREVAIL INTO SATURDAY. AS SOUTHERLY FLOW CONTINUES INTO
SATURDAY NIGHT...LOW LEVEL MOISTURE WILL INCREASE AND WILL BRING
LOW CLOUDS AND SOME PATCHY FOG/DRIZZLE TO THE AREA BY SUNRISE
SUNDAY.
LONG TERM...12Z SUNDAY THROUGH FRIDAY. THE MAIN FOCUS OF THIS
FORECAST IS ON EARLY NEXT WEEK SYSTEM...WHICH LOOKS TO BE A PRETTY
SIGNIFICANT WEATHER MAKER FOR THE AREA DURING THE MONDAY/TUESDAY
TIMEFRAME.
STARTING OUT SUNDAY MORNING...WILL BE DEALING WITH LOW CLOUDS...FOG
AND DRIZZLE ACROSS THE CWA. A WEAK SURFACE FRONT WILL BE BISECTING
THE CWA FROM NORTH TO SOUTH...WITH SOUTHERLY LOW-LEVEL FLOW AHEAD OF
THE BOUNDARY KEEPING RICH LOW-LEVEL MOISTURE IN PLACE. SOUNDINGS
CONTINUE TO SUPPORT FOG AND DRIZZLE...WITH SATURATED LOW LEVELS
BENEATH A DRY PROFILE ALOFT...AND HENCE PREFER THE INHERITED DRIZZLE
MENTION VERSUS SHOWERS. FORCING AHEAD OF AN OPEN UPPER WAVE ACTING
ON THE MOIST LOW LEVELS SHOULD BE SUFFICIENT TO SQUEEZE OUT SOME
DRIZZLE ACROSS THE EASTERN HALF OR SO OF THE CWA SUNDAY
MORNING...POSSIBLY LINGERING INTO THE AFTERNOON HOURS IN THE FAR
SOUTHEAST. TEMPERATURES ARE TRICKY ON SUNDAY. THE SURFACE BOUNDARY
WASHES OUT AND A FAIRLY WARM AIRMASS IS IN PLACE /H85 TEMPS
GENERALLY +3-5C/...BUT LOW CLOUDS WILL BE SLOW TO CLEAR ESPECIALLY
IN THE EAST. WILL AIM HIGHS IN THE MID 40S TO LOWER 50S...BUT THIS
COULD EASILY TILT EITHER WAY BASED ON CLEARING TRENDS.
SHOULD CATCH A BREAK BETWEEN SYSTEMS SUNDAY NIGHT...BEFORE A MUCH
STRONGER UPPER LOW BEGINS TO IMPACT THE AREA ON MONDAY. MODELS
/EXCLUDING THE GFS/ HAVE BEGUN TO COME INTO MUCH BETTER AGREEMENT ON
THIS EARLY WEEK SYSTEM...WITH THE TREND TOWARD A MUCH
DEEPER/STRONGER/SLOWER AND MORE IMPACTFUL SYSTEM FOR THE AREA. THE
LAST COUPLE RUNS OF BOTH THE ECMWF AND CMC GEM HAVE SHOWN THIS
SOLUTION...AND THE NAM THROUGH 84 HOURS IS ALSO CARVING OUT A DEEPER
LOW. THE GFS REMAINS THE OUTLIER IN KEEPING A MUCH MORE NORTHERN AND
PROGRESSIVE TRACK THROUGH THE PLAINS. HAVE TRENDED THE FORECAST
TOWARD THE ECMWF/GEM SOLUTION WHICH HAS MUCH MORE SUPPORT THAN THE
GFS AT THIS POINT...SEEMS MORE REALISTIC GIVEN THE UPPER JET
ENERGY DIGGING DOWN THE BACKSIDE OF THE SYSTEM...AND IS THE
PREFERRED HPC SOLUTION. FOLLOWING THIS SOLUTION...AN UPPER LOW
WILL DIG THROUGH THE CENTRAL ROCKIES...CLOSING OFF OVER NORTHWEST
KS BY MONDAY EVENING...THEN TRACKING EITHER EAST OR NORTHEAST OVER
NORTHERN KS OR SOUTHERN NE MONDAY NIGHT THROUGH TUESDAY NIGHT
BEFORE PUSHING INTO IA/MO BY WEDNESDAY. HOWEVER...THE EXACT TRACK
IT TAKES ACROSS KS/NE AND THE TIMING OF THE LOW/S MOVEMENT IS
STILL HIGHLY UNCERTAIN AND WILL HAVE A HUGE IMPACT ON THE AREA/S
WEATHER DURING THE MONDAY NIGHT THROUGH TUESDAY NIGHT TIMEFRAME.
FOR EXAMPLE...THE 20/12Z ECMWF SLOWED THE PROGRESSION OF THE
SYSTEM DOWN BY NEARLY 12 HOURS COMPARED TO THE PREVIOUS 20/00Z
RUN...WHICH OBVIOUSLY SLOWS DOWN THE INTRUSION OF COLDER AIR INTO
THE CWA ON THE BACKSIDE AND RESULTANT CHANGEOVER TO SNOW. IT WAS
LOOKING LIKE THIS CHANGEOVER WOULD OCCUR MONDAY NIGHT OVER MOST OF
THE CWA...BUT THE SLOWER 12Z ECMWF WOULD LIKELY DELAY IT UNTIL
TUESDAY FOR MOST IF NOT ALL AREAS. BY THAT TIME HOW MUCH COLD AIR
WILL BE AVAILABLE FOR THE SYSTEM TO WORK WITH COMES INTO QUESTION
SINCE THE SYSTEM IS NO LONGER DEEPENING...THEREBY SQUELCHING THE
DYNAMIC COOLING...AND THE TAP OF COLDER AIR FROM THE NORTH BEGINS
TO GET CUT OFF DUE TO THE CLOSED NATURE OF THE LOW. ON THE OTHER
HAND...THE GEM IS STILL QUITE AGGRESSIVE WITH THE COLD AIR SURGE
MONDAY NIGHT INTO TUESDAY...WHICH WOULD MEAN A SIGNIFICANT SNOW
STORM FOR THE AREA. NEEDLESS TO SAY...A LOT OF UNCERTAINTY LOOMS
WITH THIS SYSTEM. IT DOES LOOK ACTIVE/WET LATE MONDAY INTO
TUESDAY...MAYBE TUESDAY NIGHT...BUT THE DETAILS INCLUDING PRECIP
TYPE AND AMOUNT ARE STILL QUITE UNCERTAIN. MAIN CHANGES TO THE
FORECAST WERE TO INSERT/INCREASE POPS MONDAY THROUGH TUESDAY
NIGHT...COOL DAYTIME TEMPERATURES DURING THIS TIME...AND INTRODUCE
A RAIN/SNOW MIX. WINDS WILL BE PRETTY STRONG ON THE BACKSIDE OF
THE SYSTEM MONDAY NIGHT/TUESDAY...SO DEPENDING ON THE PRECIP PHASE
THIS COULD CAUSE MORE PROBLEMS. WILL HAVE TO KEEP A CLOSE EYE ON
THIS SYSTEM THROUGH THE WEEKEND...WITH MANY ADJUSTMENTS TO THE
FORECAST LIKELY YET TO COME.
FORTUNATELY...THIS SYSTEM PUSHES EAST PRIOR TO THE THANKSGIVING DAY
HOLIDAY AND THE BIG TRAVEL DAY ON WEDNESDAY. A NORTH/NORTHWEST FLOW
WILL RETURN ON WEDNESDAY IN BETWEEN THE DEPARTING SYSTEM AND UPPER
RIDGING OVER THE WESTERN CONUS. DRY CONDITIONS THEN PREVAIL
WEDNESDAY THROUGH FRIDAY AS THE WESTERN UPPER RIDGE GRADUALLY
PROPAGATES EAST. MODELS HAVE BEEN BACK AND FORTH WITH A POSSIBLE
TRAILING WAVE WEDNESDAY...WHICH COULD BRING IN A REINFORCING SHOT OF
COLDER AIR...DELAYING THE WARM-UP...BUT DOESN/T LOOK TO BRING ANY
PRECIP WITH IT. WILL SEE MODERATING TEMPERATURES WEDNESDAY THROUGH
FRIDAY AS HIGHS CLIMB BACK INTO THE 50S BY WEEK/S END...MAKING FOR A
NICE HOLIDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
AVIATION...WESELY
PREV DISCUSSION...KISNER/KB
000
FXUS63 KLBF 210306
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
906 PM CST FRI NOV 20 2009
.UPDATE...
WILL UPDATE FORECAST FOR INCREASING HIGH CLOUDS NORTHWEST LATE
THIS EVENING THROUGH SATURDAY MORNING. SOUTH TO SOUTHWESTERLY FLOW
WILL CONTINUE TO INCREASE WITH LOWER GATES AT MERRIMAN COMING UP
OVER THE LAST HOUR. THIS WILL KEEP THINGS MIXED AND TEMPERATURES
WARMER THAN THEY HAVE BEEN THE LAST COUPLE OF MORNINGS.
&&
.PREV DISCUSSION... /ISSUED 228 PM CST FRI NOV 20 2009/
DISCUSSION...
QUIET WEATHER IS EXPECTED THROUGH SATURDAY. THE POWERFUL PACIFIC
COLD ENTERING THE WRN U.S. THIS AFTN WILL WEAKEN AS IT MOVES
EAST AND IS EXPECTED TO DROP THROUGH THE FCST AREA SATURDAY NIGHT AND
BECOME STATIONARY ACROSS THE CNTL PLAINS SUNDAY MORNING. THIS FRONT
IS EXPECTED TO POOL MOISTURE ACROSS KANSAS AND NEBRASKA AND AID
RETURN MOISTURE FROM THE GULF OF MEXICO. THE NAM12 SUGGESTS STRATUS
AND FOG DEVELOPING ALONG AND EAST OF HIGHWAY 61 BEGINNING LATE
SATURDAY AND LASTING THROUGH SUNDAY AFTERNOON.
MONDAY THROUGH WEDNESDAY...THE HPC HAS LEANED STRONGLY ON THE
OPERATIONAL ECMWF. THEY BELIEVE THE MODEL HAS BEEN PERFORMING QUITE
WELL OVER THE LAST 10 DAYS AND IS THE BEST SOLN. THE GFS AND NAM12
HAVE BEEN RUNNING ABOUT 24HRS BEHIND THE ECMWF. MEANWHILE...GEM...
NOGAPS AND UKMET HAVE SUPPORTED THE ECMWF WHICH ALL SHOW A MAJOR
CYCLONE CROSSING THE CENTRAL PLAINS MONDAY THROUGH WEDNESDAY. THE
LATEST ECMWF MOVES THE STORM AT JUST 10 MPH WITH H85 WINDS INCREASING
TO NEAR 50KT. THATS DOWN FROM 65KT INDICATED IN THE 00Z ECMWF FROM
LAST NIGHT. BOTH THE ECMWF AND GFS ENSEMBLES ARE MUCH LESS
AMPLIFIED AND FEATURE A MORE OPEN WAVE SOLN.
THE ECMWF IS FCSTING ENERGY FROM A DEEP ALEUTIAN CYCLONE TO MOVE
THROUGH THE PAC NW SATURDAY NIGHT AND SOUTHEAST THROUGH WYOMING
AND INTO NRN KS MONDAY MORNING. THIS IS ATYPICAL OF CLASSIC SWRN U.S.
CUTOFF CYCLONE SYSTEMS BUT A POWERFUL PACIFIC COLD FRONT IS FCST TO
ENTER THE CNTL PLAINS MONDAY AND CHANGE RAIN TO SNOW AS THE SYSTEM
MOVES VERY SLOWLY EAST. THE 12Z ECMWF SUGGESTS A FULL BLOWN OCCLUDED
LOW AND TROWAL EVENT FOR SOUTHERN NEBRASKA. THIS IS ABOUT 100 MILES
SOUTH OF THE 00Z SOLN WHICH CARVED THE STORM THROUGH NRN NEBRASKA.
THE GEM IS VERY CLOSE TO THE 12Z ECMWF WHILE THE UKMET AND NOGAPS ARE
FARTHER SOUTH TRACKING THE STORM MORE THROUGH SRN NEB AND NORTHERN
KS. THUS IF LATER SOLNS CONTINUE TO TREND SOUTH...THE STORM COULD
MISS NEBRASKA ALL TOGETHER. STAYED TUNED.
THE OFFICIAL FCST CARRIES CHANCE 30 TO 40 PERCENT POP MONDAY
THROUGH TUESDAY NIGHT WITH RAIN CHANGING TO SNOW MONDAY NIGHT AND
CONTINUING THROUGH TUESDAY NIGHT. THIS CHANGEOVER MAY BE TOO QUICK
AND LATER FCSTS MAY HAVE TO DELAY THE CHANGEOVER UNTIL SOMETIME
TUESDAY. PRESUMABLY A RAIN SNOW LINE WILL DEVELOP NORTHWEST OF THE
SFC LOW ACROSS WHICH WILL MOVE VERY SLOWLY EAST MONDAY AND TUESDAY.
THE 12Z ECMWF IS FCSTING A 2 INCH BULLS EYE OF LIQUID PCPN JUST NORTH
OF THE H7 LOW CENTERED OVER KLBF. THE PREVIOUS 00Z RUN WAS CENTERED
OVER THE KONL-KOFK AREA AND THE 12Z RUN 24 HRS AGO WAS CENTERED
OVER KFSD. THUS THE FCST STORM TRACK WILL LIKELY CHANGE DURING THE
NEXT 72 HOURS AND THE ECMWF HAS BEEN TRENDING SOUTH. UNCERTAINTIES
WITH THIS POTENTIAL WEATHER EVENT WILL BE ADDRESSED IN THE HAZARDOUS
WEATHER OUTLOOK.
THURSDAY AND FRIDAY...PACIFIC HIGH PRESSURE WILL BUILD THROUGH THE
CENTRAL PLAINS THURSDAY IN THE WAKE OF THE STORM. LOW PRESSURE
TRACKING THROUGH THE NORTHERN PLAINS FRIDAY WILL TURN WINDS TO THE
WEST AND SOUTHWEST MODERATING TEMPERATURES.
AVIATION...
VFR CIGS/VIS WILL CONTINUE THRU AT LEAST 00Z SUN. SOUTH WINDS MAY
GET ABOVE 12KTS AT KVTN TONIGHT...AND ALMOST CERTAINLY WILL FOR A
TIME ON SATURDAY AS A LOW PRESSURE TROUGH APPROACHES. AT KLBF...
THOSE WINDS ARE UNLIKELY UNTIL AFT 18Z SATURDAY DUE TO STRONGER
LOW-LEVEL STABILITY IN THE RIVER VALLEY. AFT 00Z SUN...NORTHWARD-
MOVING MOISTURE WILL INCREASE THE CHANCE OF MVFR OR LOWER CIGS AT
KLBF...BUT THE THE ACTUAL PROBABILITY WILL DEPEND ON THE TIMING OF
THE TROUGH PASSAGE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/AVIATION...99
EXTENDED...COLE
000
FXUS63 KOAX 210304
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
904 PM CST FRI NOV 20 2009
.UPDATE...
UPDATED FOR OVERNIGHT LOWS AND TO INCLUDE FOG
&&
.DISCUSSION...
WITH CLR SKIES...LIGHT WINDS AND DRIER AIR /DRIER THAN THE LAST
SEVERAL NIGHTS/ IN PLACE...TMPS HAVE FALLEN OFF VERY FAST WITH
SOME LOCATIONS BELOW FORECAST LOWS. THUS HAVE UPDATED TO LOWER
LOWS OVERNIGHT FOR MOST AREAS. SOME INCREASE IN CI FM THE N AND AN
INCREASING PRES GRADIENT OVERNIGHT SHLD KEEP THINGS FM GETTING OUT
OF HAND. LOCAL CALLS TO THE SE COUNTIES INDC A GOOD DEAL OF HAZE
THIS EVNG AND WITH FNB ALREADY AT A 1/2SM...WL INCLUDE SOME FOG
FOR TONIGHT IN THE SRN CWA. NO PLANS FOR ADVISORY FOR TONIGHT 00Z
SOUNDINGS FM OMA/TOP INDC THE BOUNDARY LAYER IS DRIER THAN LAST
NIGHT...BUT WL CONT TO MONITOR.
NEW GRIDS/ZFP ALREADY OUT.
BOUSTEAD
&&
.AVIATION...
&&
.PREV DISCUSSION... /ISSUED 843 PM CST FRI NOV 20 2009...CORRECTED SHORT TERM/
SHORT TERM...TONIGHT THROUGH MONDAY
QUIET WEATHER CONTINUES AS HIGH PRESSURE SLIDES ACROSS THE CNTRL
PLAINS. SUBJECTIVE 12Z UPPER AIR ANALYSIS INDICATES PATTERN CHANGE
IS UNDERWAY...WITH UPPER LOW FINALLY PULLING AWAY TO THE E ACROSS
THE GT LAKES...UPPER TROUGH DIGGING ALONG THE W COAST...AND UPPER
RIDGING EXTENDING FROM THE AZ/CA BORDER THROUGH NRN MT. 1.5PVU
ANALYSIS ALSO INDICATES ELONGATED SHORTWAVE EXTENDING FROM ERN IA
THROUGH KS INTO WRN TX. SOME MOISTURE WAS CREEPING INTO THE CNTRL
PLAINS...WITH 850MB DEWPOINTS OF 2C AT KTOP AND 6C FROM SRN MO INTO
TX. WARMER TEMPS WERE NOTED ACROSS THE ROCKIES BENEATH
UPPER/MID-LEVEL RIDGING.
MAIN FORECAST CONCERN IS POTENTIAL FOR WEATHER IMPACTS AS UPPER
TROUGH DIGS INTO THE W...WITH SHORTWAVES EJECTING AHEAD OF THE MAIN
UPPER LOW. FOR TONIGHT...WX LOOKS QUIET AS UPPER-LEVEL RIDGE MOVES
EWD INTO THE CNTRL PLAINS. CLOUDS WILL BE INCREASING TO THE
S...WHICH COULD START TO SLIDE INTO THE SRN CWA BY MRNG...AND HAVE
HEDGED CLOUDS UP SLIGHTLY STARTING CLOSE TO 12Z AND CONTINUING
THROUGH THE DAY SAT AS MID-LEVEL MOISTURE ADVECTION CONTINUES.
THINK CLOUDS WILL BE ENOUGH TO TEMPER HIGHS...AND HAVE PULLED BACK
TEMPS A BIT IN THE SRN CWA. DID KEEP POPS OUT FOR NOW ON
SAT...LEANING TOWARD DRIER GEM/NAM SOLUTIONS...AS INFLUENCE OF
RIDGING LOOKS LIKELY TO PERSIST. CONTINUED DRIZZLE MENTION ON SAT
NT AS MOISTURE ADVECTION PERSISTS...WITH WEAK SHORTWAVE EVIDENT IN
QG VECTOR CONVERGENCE ADDING JUST ENOUGH LIFT FOR A LITTLE PRECIP.
INCLUDED SCHC TO CHC POPS ON SUN AS COLD FRONT APPROACHES MOIST
PRE-FRONTAL ENVIRONMENT...WITH INCREASING CHCS OF PRECIP AS THE
FRONT MOVES EWD. KEPT MAX TEMPS SOMEWHAT SUPPRESSED ON SUN AS
POTENTIAL FOR CLOUDS/LIGHT PRECIP LINGERS THROUGH A GOOD PART OF THE
DAY. FRONT IS PROGGED TO WASH OUT ON SUN NT/MON AS DEEPER UPPER LOW
DIGS INTO THE PLAINS. SOLUTIONS STILL DIFFER ON TIMING/SPEED/TRACK
OF THAT UPPER LOW...BUT DO EXPECT AT LEAST A SHORT BREAK IN PRECIP
POTENTIAL AND CLOUDS BETWEEN SYSTEMS. HAVE LEANED SLIGHTLY WARMER
ON MON IN THE SRN CWA AS A NOD TOWARD THE SLOWER/FURTHER S ECMWF
SOLUTION...PARTICULARLY IN THE SRN CWA...BUT ALSO KEPT CHC POPS
INTACT.
LONG TERM...MONDAY NIGHT THROUGH FRIDAY
CLOSED LOW WL MOVE INTO THE CNTRL PLAINS LATE MONDAY NIGHT WITH
QUITE A FEW DIFFERENCES REMAINING IN MODEL GUIDANCE. HAVE GONE WITH
THE CONSENSUS AMONG SURROUNDING OFFICES AND HPC TO FOLLOW THE 12Z
ECMWF WHICH DOES SLOW THINGS DOWN FROM THE PREVIOUS RUN. THIS WOULD
PUT THE UPPER LOW CENTERED SOMEWHERE OVER ERN KS BY 12Z WED. IT DOES
NOT LOOK LIKE MUCH COLD AIR WL BE ASSOCIATED WITH THIS SYSTEM BUT
THIS WL CERTAINLY BE MONITORED CLOSELY. CURRENT 12Z ECMWF PLACEMENT
WOULD PUT DEFORMATION ZONE ACROSS MAINLY OUR NORTHERN COUNTIES WHERE
WE HAVE HIGHEST POPS. MANY DETAILS TO BE IRONED OUT IN NEXT SEVERAL
DAYS REGARDING TRACK AND TIMING ON THIS SYSTEM.
AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VFR CONDITIONS UNDER CLEAR SKIES ARE EXPECTED THROUGH SATURDAY
AFTERNOON. PATCHY MVFR FOG MAY DEVELOP NEAR KOMA AND KLNK AROUND 12Z
SATURDAY...AND AN ISOLATED IFR VISIBILITY IS POSSIBLE.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
000
FXUS63 KOAX 210243
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
843 PM CST FRI NOV 20 2009...CORRECTED SHORT TERM
.SHORT TERM...TONIGHT THROUGH MONDAY
QUIET WEATHER CONTINUES AS HIGH PRESSURE SLIDES ACROSS THE CNTRL
PLAINS. SUBJECTIVE 12Z UPPER AIR ANALYSIS INDICATES PATTERN CHANGE
IS UNDERWAY...WITH UPPER LOW FINALLY PULLING AWAY TO THE E ACROSS
THE GT LAKES...UPPER TROUGH DIGGING ALONG THE W COAST...AND UPPER
RIDGING EXTENDING FROM THE AZ/CA BORDER THROUGH NRN MT. 1.5PVU
ANALYSIS ALSO INDICATES ELONGATED SHORTWAVE EXTENDING FROM ERN IA
THROUGH KS INTO WRN TX. SOME MOISTURE WAS CREEPING INTO THE CNTRL
PLAINS...WITH 850MB DEWPOINTS OF 2C AT KTOP AND 6C FROM SRN MO INTO
TX. WARMER TEMPS WERE NOTED ACROSS THE ROCKIES BENEATH
UPPER/MID-LEVEL RIDGING.
MAIN FORECAST CONCERN IS POTENTIAL FOR WEATHER IMPACTS AS UPPER
TROUGH DIGS INTO THE W...WITH SHORTWAVES EJECTING AHEAD OF THE MAIN
UPPER LOW. FOR TONIGHT...WX LOOKS QUIET AS UPPER-LEVEL RIDGE MOVES
EWD INTO THE CNTRL PLAINS. CLOUDS WILL BE INCREASING TO THE
S...WHICH COULD START TO SLIDE INTO THE SRN CWA BY MRNG...AND HAVE
HEDGED CLOUDS UP SLIGHTLY STARTING CLOSE TO 12Z AND CONTINUING
THROUGH THE DAY SAT AS MID-LEVEL MOISTURE ADVECTION CONTINUES.
THINK CLOUDS WILL BE ENOUGH TO TEMPER HIGHS...AND HAVE PULLED BACK
TEMPS A BIT IN THE SRN CWA. DID KEEP POPS OUT FOR NOW ON
SAT...LEANING TOWARD DRIER GEM/NAM SOLUTIONS...AS INFLUENCE OF
RIDGING LOOKS LIKELY TO PERSIST. CONTINUED DRIZZLE MENTION ON SAT
NT AS MOISTURE ADVECTION PERSISTS...WITH WEAK SHORTWAVE EVIDENT IN
QG VECTOR CONVERGENCE ADDING JUST ENOUGH LIFT FOR A LITTLE PRECIP.
INCLUDED SCHC TO CHC POPS ON SUN AS COLD FRONT APPROACHES MOIST
PRE-FRONTAL ENVIRONMENT...WITH INCREASING CHCS OF PRECIP AS THE
FRONT MOVES EWD. KEPT MAX TEMPS SOMEWHAT SUPPRESSED ON SUN AS
POTENTIAL FOR CLOUDS/LIGHT PRECIP LINGERS THROUGH A GOOD PART OF THE
DAY. FRONT IS PROGGED TO WASH OUT ON SUN NT/MON AS DEEPER UPPER LOW
DIGS INTO THE PLAINS. SOLUTIONS STILL DIFFER ON TIMING/SPEED/TRACK
OF THAT UPPER LOW...BUT DO EXPECT AT LEAST A SHORT BREAK IN PRECIP
POTENTIAL AND CLOUDS BETWEEN SYSTEMS. HAVE LEANED SLIGHTLY WARMER
ON MON IN THE SRN CWA AS A NOD TOWARD THE SLOWER/FURTHER S ECMWF
SOLUTION...PARTICULARLY IN THE SRN CWA...BUT ALSO KEPT CHC POPS
INTACT.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
CLOSED LOW WL MOVE INTO THE CNTRL PLAINS LATE MONDAY NIGHT WITH
QUITE A FEW DIFFERENCES REMAINING IN MODEL GUIDANCE. HAVE GONE WITH
THE CONSENSUS AMONG SURROUNDING OFFICES AND HPC TO FOLLOW THE 12Z
ECMWF WHICH DOES SLOW THINGS DOWN FROM THE PREVIOUS RUN. THIS WOULD
PUT THE UPPER LOW CENTERED SOMEWHERE OVER ERN KS BY 12Z WED. IT DOES
NOT LOOK LIKE MUCH COLD AIR WL BE ASSOCIATED WITH THIS SYSTEM BUT
THIS WL CERTAINLY BE MONITORED CLOSELY. CURRENT 12Z ECMWF PLACEMENT
WOULD PUT DEFORMATION ZONE ACROSS MAINLY OUR NORTHERN COUNTIES WHERE
WE HAVE HIGHEST POPS. MANY DETAILS TO BE IRONED OUT IN NEXT SEVERAL
DAYS REGARDING TRACK AND TIMING ON THIS SYSTEM.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VFR CONDITIONS UNDER CLEAR SKIES ARE EXPECTED THROUGH SATURDAY
AFTERNOON. PATCHY MVFR FOG MAY DEVELOP NEAR KOMA AND KLNK AROUND 12Z
SATURDAY...AND AN ISOLATED IFR VISIBILITY IS POSSIBLE.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...MAYES
LONG TERM...KERN
AVIATION...DERGAN
000
FXUS63 KGID 202341
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
541 PM CST FRI NOV 20 2009
.AVIATION...00Z KGRI TAF. SOUTH WINDS WILL CONTINUE THROUGH THE
TAF VALID PERIOD AND INCREASE DURING THE DAY TOMORROW. THESE WINDS
WILL BEGIN TO PUMP MOISTURE NORTHWARD...WHICH COULD RESULT IN A
LOW STRATUS DECK BEGINNING SHORTLY AFTER SUNRISE TOMORROW. THERE
IS STILL SOME UNCERTAINTY AS TO HOW FAR NORTH THE STRATUS DECK WILL
MAKE IT...AND WHETHER OR NOT IT WILL REACH KGRI. HOWEVER...THE
POSSIBILITY OF THESE IFR CEILINGS SEEMS HIGH ENOUGH TO WARRANT
INCLUSION IN THE TAF AND LOW CLOUDS COULD PERSIST THROUGH EARLY
AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 338 PM CST FRI NOV 20 2009/
SHORT TERM...TONIGHT THROUGH 12Z SUNDAY. NOT MUCH IN THE WAY OF
WEATHER IN THIS PERIOD. SURFACE RIDGE IS MOVING ACROSS THE AREA THIS
AFTERNOON WITH SOUTHERLY FLOW RETURNING. SURFACE TROUGH WILL DEVELOP
AND STRENGTHEN ACROSS THE WESTERN HIGH PLAINS TONIGHT AND
SATURDAY. THIS WILL INCREASE THE PRESSURE GRADIENT AND SO WILL THE
WINDS. EXPECT A BREEZY DAY ON SATURDAY WITH SOUTH WINDS OF 15 TO
25 MPH. LITTLE IN THE WAY OF MOISTURE IN PLACE NOW SO CLEAR SKIES
WILL PREVAIL INTO SATURDAY. AS SOUTHERLY FLOW CONTINUES INTO
SATURDAY NIGHT...LOW LEVEL MOISTURE WILL INCREASE AND WILL BRING
LOW CLOUDS AND SOME PATCHY FOG/DRIZZLE TO THE AREA BY SUNRISE
SUNDAY.
LONG TERM...12Z SUNDAY THROUGH FRIDAY. THE MAIN FOCUS OF THIS
FORECAST IS ON EARLY NEXT WEEK SYSTEM...WHICH LOOKS TO BE A PRETTY
SIGNIFICANT WEATHER MAKER FOR THE AREA DURING THE MONDAY/TUESDAY
TIMEFRAME.
STARTING OUT SUNDAY MORNING...WILL BE DEALING WITH LOW CLOUDS...FOG
AND DRIZZLE ACROSS THE CWA. A WEAK SURFACE FRONT WILL BE BISECTING
THE CWA FROM NORTH TO SOUTH...WITH SOUTHERLY LOW-LEVEL FLOW AHEAD OF
THE BOUNDARY KEEPING RICH LOW-LEVEL MOISTURE IN PLACE. SOUNDINGS
CONTINUE TO SUPPORT FOG AND DRIZZLE...WITH SATURATED LOW LEVELS
BENEATH A DRY PROFILE ALOFT...AND HENCE PREFER THE INHERITED DRIZZLE
MENTION VERSUS SHOWERS. FORCING AHEAD OF AN OPEN UPPER WAVE ACTING
ON THE MOIST LOW LEVELS SHOULD BE SUFFICIENT TO SQUEEZE OUT SOME
DRIZZLE ACROSS THE EASTERN HALF OR SO OF THE CWA SUNDAY
MORNING...POSSIBLY LINGERING INTO THE AFTERNOON HOURS IN THE FAR
SOUTHEAST. TEMPERATURES ARE TRICKY ON SUNDAY. THE SURFACE BOUNDARY
WASHES OUT AND A FAIRLY WARM AIRMASS IS IN PLACE /H85 TEMPS
GENERALLY +3-5C/...BUT LOW CLOUDS WILL BE SLOW TO CLEAR ESPECIALLY
IN THE EAST. WILL AIM HIGHS IN THE MID 40S TO LOWER 50S...BUT THIS
COULD EASILY TILT EITHER WAY BASED ON CLEARING TRENDS.
SHOULD CATCH A BREAK BETWEEN SYSTEMS SUNDAY NIGHT...BEFORE A MUCH
STRONGER UPPER LOW BEGINS TO IMPACT THE AREA ON MONDAY. MODELS
/EXCLUDING THE GFS/ HAVE BEGUN TO COME INTO MUCH BETTER AGREEMENT ON
THIS EARLY WEEK SYSTEM...WITH THE TREND TOWARD A MUCH
DEEPER/STRONGER/SLOWER AND MORE IMPACTFUL SYSTEM FOR THE AREA. THE
LAST COUPLE RUNS OF BOTH THE ECMWF AND CMC GEM HAVE SHOWN THIS
SOLUTION...AND THE NAM THROUGH 84 HOURS IS ALSO CARVING OUT A DEEPER
LOW. THE GFS REMAINS THE OUTLIER IN KEEPING A MUCH MORE NORTHERN AND
PROGRESSIVE TRACK THROUGH THE PLAINS. HAVE TRENDED THE FORECAST
TOWARD THE ECMWF/GEM SOLUTION WHICH HAS MUCH MORE SUPPORT THAN THE
GFS AT THIS POINT...SEEMS MORE REALISTIC GIVEN THE UPPER JET
ENERGY DIGGING DOWN THE BACKSIDE OF THE SYSTEM...AND IS THE
PREFERRED HPC SOLUTION. FOLLOWING THIS SOLUTION...AN UPPER LOW
WILL DIG THROUGH THE CENTRAL ROCKIES...CLOSING OFF OVER NORTHWEST
KS BY MONDAY EVENING...THEN TRACKING EITHER EAST OR NORTHEAST OVER
NORTHERN KS OR SOUTHERN NE MONDAY NIGHT THROUGH TUESDAY NIGHT
BEFORE PUSHING INTO IA/MO BY WEDNESDAY. HOWEVER...THE EXACT TRACK
IT TAKES ACROSS KS/NE AND THE TIMING OF THE LOW/S MOVEMENT IS
STILL HIGHLY UNCERTAIN AND WILL HAVE A HUGE IMPACT ON THE AREA/S
WEATHER DURING THE MONDAY NIGHT THROUGH TUESDAY NIGHT TIMEFRAME.
FOR EXAMPLE...THE 20/12Z ECMWF SLOWED THE PROGRESSION OF THE
SYSTEM DOWN BY NEARLY 12 HOURS COMPARED TO THE PREVIOUS 20/00Z
RUN...WHICH OBVIOUSLY SLOWS DOWN THE INTRUSION OF COLDER AIR INTO
THE CWA ON THE BACKSIDE AND RESULTANT CHANGEOVER TO SNOW. IT WAS
LOOKING LIKE THIS CHANGEOVER WOULD OCCUR MONDAY NIGHT OVER MOST OF
THE CWA...BUT THE SLOWER 12Z ECMWF WOULD LIKELY DELAY IT UNTIL
TUESDAY FOR MOST IF NOT ALL AREAS. BY THAT TIME HOW MUCH COLD AIR
WILL BE AVAILABLE FOR THE SYSTEM TO WORK WITH COMES INTO QUESTION
SINCE THE SYSTEM IS NO LONGER DEEPENING...THEREBY SQUELCHING THE
DYNAMIC COOLING...AND THE TAP OF COLDER AIR FROM THE NORTH BEGINS
TO GET CUT OFF DUE TO THE CLOSED NATURE OF THE LOW. ON THE OTHER
HAND...THE GEM IS STILL QUITE AGGRESSIVE WITH THE COLD AIR SURGE
MONDAY NIGHT INTO TUESDAY...WHICH WOULD MEAN A SIGNIFICANT SNOW
STORM FOR THE AREA. NEEDLESS TO SAY...A LOT OF UNCERTAINTY LOOMS
WITH THIS SYSTEM. IT DOES LOOK ACTIVE/WET LATE MONDAY INTO
TUESDAY...MAYBE TUESDAY NIGHT...BUT THE DETAILS INCLUDING PRECIP
TYPE AND AMOUNT ARE STILL QUITE UNCERTAIN. MAIN CHANGES TO THE
FORECAST WERE TO INSERT/INCREASE POPS MONDAY THROUGH TUESDAY
NIGHT...COOL DAYTIME TEMPERATURES DURING THIS TIME...AND INTRODUCE
A RAIN/SNOW MIX. WINDS WILL BE PRETTY STRONG ON THE BACKSIDE OF
THE SYSTEM MONDAY NIGHT/TUESDAY...SO DEPENDING ON THE PRECIP PHASE
THIS COULD CAUSE MORE PROBLEMS. WILL HAVE TO KEEP A CLOSE EYE ON
THIS SYSTEM THROUGH THE WEEKEND...WITH MANY ADJUSTMENTS TO THE
FORECAST LIKELY YET TO COME.
FORTUNATELY...THIS SYSTEM PUSHES EAST PRIOR TO THE THANKSGIVING DAY
HOLIDAY AND THE BIG TRAVEL DAY ON WEDNESDAY. A NORTH/NORTHWEST FLOW
WILL RETURN ON WEDNESDAY IN BETWEEN THE DEPARTING SYSTEM AND UPPER
RIDGING OVER THE WESTERN CONUS. DRY CONDITIONS THEN PREVAIL
WEDNESDAY THROUGH FRIDAY AS THE WESTERN UPPER RIDGE GRADUALLY
PROPAGATES EAST. MODELS HAVE BEEN BACK AND FORTH WITH A POSSIBLE
TRAILING WAVE WEDNESDAY...WHICH COULD BRING IN A REINFORCING SHOT OF
COLDER AIR...DELAYING THE WARM-UP...BUT DOESN/T LOOK TO BRING ANY
PRECIP WITH IT. WILL SEE MODERATING TEMPERATURES WEDNESDAY THROUGH
FRIDAY AS HIGHS CLIMB BACK INTO THE 50S BY WEEK/S END...MAKING FOR A
NICE HOLIDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
DISCUSSION...KISNER/KB
000
FXUS63 KGID 202138
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
338 PM CST FRI NOV 20 2009
.SHORT TERM...TONIGHT THROUGH 12Z SUNDAY. NOT MUCH IN THE WAY OF
WEATHER IN THIS PERIOD. SURFACE RIDGE IS MOVING ACROSS THE AREA THIS
AFTERNOON WITH SOUTHERLY FLOW RETURNING. SURFACE TROF WILL DEVELOP
AND STRENGTHEN ACROSS THE WESTERN HIGH PLAINS TONIGHT AND SATURDAY.
THIS WILL INCREASE THE PRESSURE GRADIENT AND SO WILL THE WINDS.
EXPECT A BREEZY DAY ON SATURDAY WITH SOUTH WINDS OF 15 TO 25 MPH.
LITTLE IN THE WAY OF MOISTURE IN PLACE NOW SO CLEAR SKIES WILL
PREVAIL INTO SATURDAY. AS SOUTHERLY FLOW CONTINUES INTO SATURDAY
NIGHT...LOW LEVEL MOISTURE WILL INCREASE AND WILL BRING LOW CLOUDS
AND SOME PATCHY FOG/DRIZZLE TO THE AREA BY SUNRISE SUNDAY.
.LONG TERM...12Z SUNDAY THROUGH FRIDAY. THE MAIN FOCUS OF THIS
FORECAST IS ON EARLY NEXT WEEK SYSTEM...WHICH LOOKS TO BE A PRETTY
SIGNIFICANT WEATHER MAKER FOR THE AREA DURING THE MONDAY/TUESDAY
TIMEFRAME.
STARTING OUT SUNDAY MORNING...WILL BE DEALING WITH LOW CLOUDS...FOG
AND DRIZZLE ACROSS THE CWA. A WEAK SURFACE FRONT WILL BE BISECTING
THE CWA FROM NORTH TO SOUTH...WITH SOUTHERLY LOW-LEVEL FLOW AHEAD OF
THE BOUNDARY KEEPING RICH LOW-LEVEL MOISTURE IN PLACE. SOUNDINGS
CONTINUE TO SUPPORT FOG AND DRIZZLE...WITH SATURATED LOW LEVELS
BENEATH A DRY PROFILE ALOFT...AND HENCE PREFER THE INHERITED DRIZZLE
MENTION VERSUS SHOWERS. FORCING AHEAD OF AN OPEN UPPER WAVE ACTING
ON THE MOIST LOW LEVELS SHOULD BE SUFFICIENT TO SQUEEZE OUT SOME
DRIZZLE ACROSS THE EASTERN HALF OR SO OF THE CWA SUNDAY
MORNING...POSSIBLY LINGERING INTO THE AFTERNOON HOURS IN THE FAR
SOUTHEAST. TEMPERATURES ARE TRICKY ON SUNDAY. THE SURFACE BOUNDARY
WASHES OUT AND A FAIRLY WARM AIRMASS IS IN PLACE /H85 TEMPS
GENERALLY +3-5C/...BUT LOW CLOUDS WILL BE SLOW TO CLEAR ESPECIALLY
IN THE EAST. WILL AIM HIGHS IN THE MID 40S TO LOWER 50S...BUT THIS
COULD EASILY TILT EITHER WAY BASED ON CLEARING TRENDS.
SHOULD CATCH A BREAK BETWEEN SYSTEMS SUNDAY NIGHT...BEFORE A MUCH
STRONGER UPPER LOW BEGINS TO IMPACT THE AREA ON MONDAY. MODELS
/EXCLUDING THE GFS/ HAVE BEGUN TO COME INTO MUCH BETTER AGREEMENT ON
THIS EARLY WEEK SYSTEM...WITH THE TREND TOWARD A MUCH
DEEPER/STRONGER/SLOWER AND MORE IMPACTFUL SYSTEM FOR THE AREA. THE
LAST COUPLE RUNS OF BOTH THE ECMWF AND CMC GEM HAVE SHOWN THIS
SOLUTION...AND THE NAM THROUGH 84 HOURS IS ALSO CARVING OUT A DEEPER
LOW. THE GFS REMAINS THE OUTLIER IN KEEPING A MUCH MORE NORTHERN AND
PROGRESSIVE TRACK THROUGH THE PLAINS. HAVE TRENDED THE FORECAST
TOWARD THE ECMWF/GEM SOLUTION WHICH HAS MUCH MORE SUPPORT THAN THE
GFS AT THIS POINT...SEEMS MORE REALISTIC GIVEN THE UPPER JET
ENERGY DIGGING DOWN THE BACKSIDE OF THE SYSTEM...AND IS THE
PREFERRED HPC SOLUTION. FOLLOWING THIS SOLUTION...AN UPPER LOW
WILL DIG THROUGH THE CENTRAL ROCKIES...CLOSING OFF OVER NORTHWEST
KS BY MONDAY EVENING...THEN TRACKING EITHER EAST OR NORTHEAST OVER
NORTHERN KS OR SOUTHERN NE MONDAY NIGHT THROUGH TUESDAY NIGHT
BEFORE PUSHING INTO IA/MO BY WEDNESDAY. HOWEVER...THE EXACT TRACK
IT TAKES ACROSS KS/NE AND THE TIMING OF THE LOW/S MOVEMENT IS
STILL HIGHLY UNCERTAIN AND WILL HAVE A HUGE IMPACT ON THE AREA/S
WEATHER DURING THE MONDAY NIGHT THROUGH TUESDAY NIGHT TIMEFRAME.
FOR EXAMPLE...THE 20/12Z ECMWF SLOWED THE PROGRESSION OF THE
SYSTEM DOWN BY NEARLY 12 HOURS COMPARED TO THE PREVIOUS 20/00Z
RUN...WHICH OBVIOUSLY SLOWS DOWN THE INTRUSION OF COLDER AIR INTO
THE CWA ON THE BACKSIDE AND RESULTANT CHANGEOVER TO SNOW. IT WAS
LOOKING LIKE THIS CHANGEOVER WOULD OCCUR MONDAY NIGHT OVER MOST OF
THE CWA...BUT THE SLOWER 12Z ECMWF WOULD LIKELY DELAY IT UNTIL
TUESDAY FOR MOST IF NOT ALL AREAS. BY THAT TIME HOW MUCH COLD AIR
WILL BE AVAILABLE FOR THE SYSTEM TO WORK WITH COMES INTO QUESTION
SINCE THE SYSTEM IS NO LONGER DEEPENING...THEREBY SQUELCHING THE
DYNAMIC COOLING...AND THE TAP OF COLDER AIR FROM THE NORTH BEGINS
TO GET CUT OFF DUE TO THE CLOSED NATURE OF THE LOW. ON THE OTHER
HAND...THE GEM IS STILL QUITE AGGRESSIVE WITH THE COLD AIR SURGE
MONDAY NIGHT INTO TUESDAY...WHICH WOULD MEAN A SIGNIFICANT SNOW
STORM FOR THE AREA. NEEDLESS TO SAY...A LOT OF UNCERTAINTY LOOMS
WITH THIS SYSTEM. IT DOES LOOK ACTIVE/WET LATE MONDAY INTO
TUESDAY...MAYBE TUESDAY NIGHT...BUT THE DETAILS INCLUDING PRECIP
TYPE AND AMOUNT ARE STILL QUITE UNCERTAIN. MAIN CHANGES TO THE
FORECAST WERE TO INSERT/INCREASE POPS MONDAY THROUGH TUESDAY
NIGHT...COOL DAYTIME TEMPERATURES DURING THIS TIME...AND INTRODUCE
A RAIN/SNOW MIX. WINDS WILL BE PRETTY STRONG ON THE BACKSIDE OF
THE SYSTEM MONDAY NIGHT/TUESDAY...SO DEPENDING ON THE PRECIP PHASE
THIS COULD CAUSE MORE PROBLEMS. WILL HAVE TO KEEP A CLOSE EYE ON
THIS SYSTEM THROUGH THE WEEKEND...WITH MANY ADJUSTMENTS TO THE
FORECAST LIKELY YET TO COME.
FORTUNATELY...THIS SYSTEM PUSHES EAST PRIOR TO THE THANKSGIVING DAY
HOLIDAY AND THE BIG TRAVEL DAY ON WEDNESDAY. A NORTH/NORTHWEST FLOW
WILL RETURN ON WEDNESDAY IN BETWEEN THE DEPARTING SYSTEM AND UPPER
RIDGING OVER THE WESTERN CONUS. DRY CONDITIONS THEN PREVAIL
WEDNESDAY THROUGH FRIDAY AS THE WESTERN UPPER RIDGE GRADUALLY
PROPAGATES EAST. MODELS HAVE BEEN BACK AND FORTH WITH A POSSIBLE
TRAILING WAVE WEDNESDAY...WHICH COULD BRING IN A REINFORCING SHOT OF
COLDER AIR...DELAYING THE WARM-UP...BUT DOESN/T LOOK TO BRING ANY
PRECIP WITH IT. WILL SEE MODERATING TEMPERATURES WEDNESDAY THROUGH
FRIDAY AS HIGHS CLIMB BACK INTO THE 50S BY WEEK/S END...MAKING FOR A
NICE HOLIDAY.
&&
.AVIATION...18Z KGRI TAF. SURFACE RIDGE WILL CONTINUE TO MOVE ACROSS
THE REGION THIS AFTERNOON. THIS WILL BRING CLEAR SKIES AND LIGHT
WINDS. RIDGE WILL BE EAST OF KGRI BY 21/00Z AND WINDS WILL TURN TO
THE SOUTH. SKIES WILL REMAIN CLEAR/VFR THROUGH THE FORECAST PERIOD.
SOUTH SURFACE WINDS WILL INCREASE INTO THE 15 KNOT RANGE BY
MID-MORNING SATURDAY AND WILL BE OCCASIONALLY GUSTY DURING THE
AFTERNOON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
KISNER/KB
000
FXUS63 KOAX 202129
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
329 PM CST FRI NOV 20 2009
.SHORT TERM...TONIGHT THROUGH MONDAY
WARM WEATHER CONTINUES...WITH PRECIP OUT OF THE CWA SO FAR TODAY.
SUBJECTIVE 12Z UPPER AIR ANALYSIS INDICATES SWLY UPPER-LEVEL FLOW
OVER THE CNTRL US...WITH BROAD WRN US TROUGH AND ERN US RIDGE.
UPPER LOW WAS NOTED OFF THE BC COAST. 850MB PATTERN WAS
MESSY...WITH RIDGING EXTENDING FROM VA WWD INTO SERN KS...BUT TROUGH
ALSO EVIDENT FROM ERN WI THROUGH NERN KS INTO THE TX PANHANDLE.
850MB 8C+ MOISTURE AXIS EXTENDED FROM TX INTO NERN KS/NRN MO ALONG/S
OF TROUGH...WITH SHARP CUTOFF TO DRIER AIR NORTH AS KOMA DEWPOINT
CAME IN AT -13C. SFC HIGH AT 20Z WAS CENTERED IN SERN SD/NERN
NEB...WITH SFC FRONT EXTENDING FROM CNTRL MO WWD THROUGH SERN
KS/NWRN OK.
MAIN FORECAST CONCERN LIES IN CLOUD POTENTIAL...AS PRECIP THROUGH
FRI LARGELY MISSES THE CWA. SHRA MAY JUST CLIP THE FAR SERN CORNER
OF NEB THIS EVNG...WITH ELEVATED INSTABILITY AND 850MB FGEN
REMAINING S OF THE CWA...AND HAVE KEPT A CHC POP THERE.
OTHERWISE...SKIES SHOULD CLEAR THROUGH THE NIGHT...WITH LIGHT
WINDS. HAVE KEPT TEMPS ON THE COOL SIDE N...AND CLOSER TO 40 SOUTH
WHERE CLOUDS WILL LINGER LONGEST. FAIR WEATHER WILL CONTINUE
TMRW...WITH WINDS VEERING FROM ERLY TO SERLY. HAVE BUMPED UP TEMPS
A TOUCH AS TEMPS TODAY HAVE BEEN ABLE TO RISE INTO THE MID-60S IN
THE SRN CWA DESPITE A FEW CLOUDS AND NERLY WINDS. ON TUES NT...GFS
AND TO SOME EXTENT NAM DRAW SHALLOW LOW-LEVEL MOISTURE INTO CNTRL
NEB...INDICATING A DEVELOPING CLOUD DECK AND DZ. HAVE SEEN THIS
PATTERN RECENTLY IN THE MODELS RECENTLY...ONLY WITHOUT ANY RESULTING
CLOUDS/DZ. HAVE KEPT A CLOUD MENTION IN THE WRN CWA...THOUGH
CONFIDENCE IS LOW...BUT DID REMOVE DZ AS IT IS A NON-MEASURABLE
MENTION ANYWAY AND CAN EASILY BE ADDED BACK IN IF LOW-LEVEL MOISTURE
DEVELOPS. KEPT CLOUDS GOING THROUGH WED/WED NT...PARTICULARLY IN
THE NRN CWA...BUT CONTINUED TO KEEP OUT ANY PRECIP MENTION. WITH
LINGERING CLOUDS...LOWERED MAX T FOR WED IN THE NWRN CWA IN
PARTICULAR AND RAISED TEMPS TUES NT IN THE WEST AND WED NT ACROSS
MUCH OF THE CWA. FOR THURS...MODEL CONSENSUS INDICATES BULK OF
CLOUDS WILL BE THROUGH THE CWA...WITH INCREASING SRLY FLOW AT THE
SFC AND SWLY FLOW ALOFT DRAGGING WARMER LOW/MID-LEVEL AIR INTO THE
CWA. HAVE RAISED MAX TEMPS ACROSS THE CWA THURS IN RESPONSE.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
CLOSED LOW WL MOVE INTO THE CNTRL PLAINS LATE MONDAY NIGHT WITH
QUITE A FEW DIFFERENCES REMAINING IN MODEL GUIDANCE. HAVE GONE WITH
THE CONSENSUS AMONG SURROUNDING OFFICES AND HPC TO FOLLOW THE 12Z
ECMWF WHICH DOES SLOW THINGS DOWN FROM THE PREVIOUS RUN. THIS WOULD
PUT THE UPPER LOW CENTERED SOMEWHERE OVER ERN KS BY 12Z WED. IT DOES
NOT LOOK LIKE MUCH COLD AIR WL BE ASSOCIATED WITH THIS SYSTEM BUT
THIS WL CERTAINLY BE MONITORED CLOSELY. CURRENT 12Z ECMWF PLACEMENT
WOULD PUT DEFORMATION ZONE ACROSS MAINLY OUR NORTHERN COUNTIES WHERE
WE HAVE HIGHEST POPS. MANY DETAILS TO BE IRONED OUT IN NEXT SEVERAL
DAYS REGARDING TRACK AND TIMING ON THIS SYSTEM.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VFR CONDITIONS UNDER CLEAR SKIES ARE EXPECTED THROUGH SATURDAY
AFTERNOON. PATCHY MVFR FOG MAY DEVELOP NEAR KOMA AND KLNK AROUND 12Z
SATURDAY...AND AN ISOLATED IFR VISIBILITY IS POSSIBLE.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...MAYES
LONG TERM...KERN
AVIATION...DERGAN
000
FXUS63 KLBF 202028
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
228 PM CST FRI NOV 20 2009
.DISCUSSION...
QUIET WEATHER IS EXPECTED THROUGH SATURDAY. THE POWERFUL PACIFIC
COLD ENTERING THE WRN U.S. THIS AFTN WILL WEAKEN AS IT MOVES
EAST AND IS EXPECTED TO DROP THROUGH THE FCST AREA SATURDAY NIGHT AND
BECOME STATIONARY ACROSS THE CNTL PLAINS SUNDAY MORNING. THIS FRONT
IS EXPECTED TO POOL MOISTURE ACROSS KANSAS AND NEBRASKA AND AID
RETURN MOISTURE FROM THE GULF OF MEXICO. THE NAM12 SUGGESTS STRATUS
AND FOG DEVELOPING ALONG AND EAST OF HIGHWAY 61 BEGINNING LATE
SATURDAY AND LASTING THROUGH SUNDAY AFTERNOON.
MONDAY THROUGH WEDNESDAY...THE HPC HAS LEANED STRONGLY ON THE
OPERATIONAL ECMWF. THEY BELIEVE THE MODEL HAS BEEN PERFORMING QUITE
WELL OVER THE LAST 10 DAYS AND IS THE BEST SOLN. THE GFS AND NAM12
HAVE BEEN RUNNING ABOUT 24HRS BEHIND THE ECMWF. MEANWHILE...GEM...
NOGAPS AND UKMET HAVE SUPPORTED THE ECMWF WHICH ALL SHOW A MAJOR
CYCLONE CROSSING THE CENTRAL PLAINS MONDAY THROUGH WEDNESDAY. THE
LATEST ECMWF MOVES THE STORM AT JUST 10 MPH WITH H85 WINDS INCREASING
TO NEAR 50KT. THATS DOWN FROM 65KT INDICATED IN THE 00Z ECMWF FROM
LAST NIGHT. BOTH THE ECMWF AND GFS ENSEMBLES ARE MUCH LESS
AMPLIFIED AND FEATURE A MORE OPEN WAVE SOLN.
THE ECMWF IS FCSTING ENERGY FROM A DEEP ALEUTIAN CYCLONE TO MOVE
THROUGH THE PAC NW SATURDAY NIGHT AND SOUTHEAST THROUGH WYOMING
AND INTO NRN KS MONDAY MORNING. THIS IS ATYPICAL OF CLASSIC SWRN U.S.
CUTOFF CYCLONE SYSTEMS BUT A POWERFUL PACIFIC COLD FRONT IS FCST TO
ENTER THE CNTL PLAINS MONDAY AND CHANGE RAIN TO SNOW AS THE SYSTEM
MOVES VERY SLOWLY EAST. THE 12Z ECMWF SUGGESTS A FULL BLOWN OCCLUDED
LOW AND TROWAL EVENT FOR SOUTHERN NEBRASKA. THIS IS ABOUT 100 MILES
SOUTH OF THE 00Z SOLN WHICH CARVED THE STORM THROUGH NRN NEBRASKA.
THE GEM IS VERY CLOSE TO THE 12Z ECMWF WHILE THE UKMET AND NOGAPS ARE
FARTHER SOUTH TRACKING THE STORM MORE THROUGH SRN NEB AND NORTHERN
KS. THUS IF LATER SOLNS CONTINUE TO TREND SOUTH...THE STORM COULD
MISS NEBRASKA ALL TOGETHER. STAYED TUNED.
THE OFFICIAL FCST CARRIES CHANCE 30 TO 40 PERCENT POP MONDAY
THROUGH TUESDAY NIGHT WITH RAIN CHANGING TO SNOW MONDAY NIGHT AND
CONTINUING THROUGH TUESDAY NIGHT. THIS CHANGEOVER MAY BE TOO QUICK
AND LATER FCSTS MAY HAVE TO DELAY THE CHANGEOVER UNTIL SOMETIME
TUESDAY. PRESUMABLY A RAIN SNOW LINE WILL DEVELOP NORTHWEST OF THE
SFC LOW ACROSS WHICH WILL MOVE VERY SLOWLY EAST MONDAY AND TUESDAY.
THE 12Z ECMWF IS FCSTING A 2 INCH BULLS EYE OF LIQUID PCPN JUST NORTH
OF THE H7 LOW CENTERED OVER KLBF. THE PREVIOUS 00Z RUN WAS CENTERED
OVER THE KONL-KOFK AREA AND THE 12Z RUN 24 HRS AGO WAS CENTERED
OVER KFSD. THUS THE FCST STORM TRACK WILL LIKELY CHANGE DURING THE
NEXT 72 HOURS AND THE ECMWF HAS BEEN TRENDING SOUTH. UNCERTAINTIES
WITH THIS POTENTIAL WEATHER EVENT WILL BE ADDRESSED IN THE HAZARDOUS
WEATHER OUTLOOK.
THURSDAY AND FRIDAY...PACIFIC HIGH PRESSURE WILL BUILD THROUGH THE
CENTRAL PLAINS THURSDAY IN THE WAKE OF THE STORM. LOW PRESSURE
TRACKING THROUGH THE NORTHERN PLAINS FRIDAY WILL TURN WINDS TO THE
WEST AND SOUTHWEST MODERATING TEMPERATURES.
&&
.AVIATION...
VFR CIGS/VIS WILL CONTINUE THRU AT LEAST 00Z SUN. SOUTH WINDS MAY
GET ABOVE 12KTS AT KVTN TONIGHT...AND ALMOST CERTAINLY WILL FOR A
TIME ON SATURDAY AS A LOW PRESSURE TROUGH APPROACHES. AT KLBF...
THOSE WINDS ARE UNLIKELY UNTIL AFT 18Z SATURDAY DUE TO STRONGER
LOW-LEVEL STABILITY IN THE RIVER VALLEY. AFT 00Z SUN...NORTHWARD-
MOVING MOISTURE WILL INCREASE THE CHANCE OF MVFR OR LOWER CIGS AT
KLBF...BUT THE THE ACTUAL PROBABILITY WILL DEPEND ON THE TIMING OF
THE TROUGH PASSAGE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
CDC/CS/TLK
000
FXUS63 KGID 201720
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1120 AM CST FRI NOV 20 2009
.AVIATION...18Z KGRI TAF. SURFACE RIDGE WILL CONTINUE TO MOVE ACROSS
THE REGION THIS AFTERNOON. THIS WILL BRING CLEAR SKIES AND LIGHT
WINDS. RIDGE WILL BE EAST OF KGRI BY 21/00Z AND WINDS WILL TURN TO
THE SOUTH. SKIES WILL REMAIN CLEAR/VFR THROUGH THE FORECAST PERIOD.
SOUTH SURFACE WINDS WILL INCREASE INTO THE 15 KNOT RANGE BY
MID-MORNING SATURDAY AND WILL BE OCCASIONALLY GUSTY DURING THE
AFTERNOON. -KISNER
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
000
FXUS63 KGID 201138
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
538 AM CST FRI NOV 20 2009
.AVIATION...12Z TAF. SO FAR FOG DEVELOPMENT IN THE RADIATIONAL
CONDITIONS HAVE BEEN CONFINED TO LOCATIONS EAST OF KGRI. A
WESTERLY DOWNSLOPE WIND COMPONENT AT KGRI AND AND POINTS WEST SEEM
TO HAVE PRECLUDED THE FOG DEVELOPMENT THIS MORNING AND THEREFORE
HAVE LEFT FOG OUT OF THE FORECAST. VFR CONDITIONS ARE EXPECTED
THROUGH THE DAY. WINDS WILL BE FAIRLY VARIABLE FOR THE MOST PART
BUT WILL TRANSITION SOUTHERLY AFTER DARK. LITTLE IF ANY CLOUD
COVER IS EXPECTED.
&&
.PREV DISCUSSION... /ISSUED 308 AM CST FRI NOV 20 2009/
DISCUSSION...EARLY MORNING WATER VAPOR IMAGERY SHOWED A WAVE
MOVING ACROSS THE REGION...THOUGH A LACK OF MOISTURE WAS KEEPING
IT MAINLY CLEAR ACROSS THE FORECAST AREA. GENERALLY CLEAR SKIES
ARE EXPECTED TO PREVAIL MOST OF THE DAY...THOUGH THERE COULD BE A
FEW HIGH CLOUDS SPILLING INTO THE REGION AS AN UPPER RIDGE BUILDS
IN BEHIND THE PASSING WAVE. THERE COULD ALSO BE PATCHY FOG THIS
MORNING...ESPECIALLY IN THE EASTERN PORTION OF THE FORECAST AREA
WHERE WINDS ARE NEARLY CALM. TEMPERATURES WILL REMAIN CLOSE TO 10
DEGREES ABOVE NORMAL FOR TODAY WITH HIGHS EXPECTED TO BE IN THE
MID 50S. IT WILL REMAIN RELATIVELY QUIET AGAIN TONIGHT AS THE
UPPER RIDGE DOMINATES THE REGIONS WEATHER. THIS SHOULD KEEP SKIES
CLEAR TO AT MOST PARTLY CLOUDY. LOWS TONIGHT WILL BE IN THE MID
20S TO LOWER 30S.
THE NEXT UPPER WAVE BEGINS TO APPROACH ON SATURDAY...AND MOVES
ACROSS THE FORECAST AREA SATURDAY NIGHT INTO EARLY SUNDAY. THE
WAVE ALSO BRINGS A COLD FRONT ACROSS THE REGION...WITH BOTH THE
00Z NAM AND GFS SHOWING INCREASING LOW LEVEL MOISTURE AHEAD OF THE
FRONT. THERE COULD BE SOME INCREASE IN LOW CLOUDS ALREADY ON
SATURDAY AFTERNOON IN THE EASTERN PORTION OF THE FORECAST
AREA...BUT THE MAJORITY OF THE CLOUDS APPEAR TO HOLD OFF UNTIL
SATURDAY NIGHT WHEN MOST IF NOT ALL OF THE FORECAST AREA SHOULD
GET COVERED BY STRATUS. THE POSSIBILITY OF INCREASING LOW CLOUDS
IN THE EAST ON SATURDAY AFTERNOON COULD MAKE HIGHS A BIT
TRICKY...BUT FOR NOW WILL AGAIN GO WITH MID 50S OVER MOST OF THE
FORECAST AREA.
IT APPEARS THAT THERE COULD BE SOME DRIZZLE AND FOG AHEAD OF THE
FRONTAL BOUNDARY SATURDAY NIGHT INTO EARLY SUNDAY. FORECAST
SOUNDINGS FROM ACROSS THE FORECAST AREA SHOW VERY LIMITED MOISTURE
ABOVE H85...WITH NEARLY SATURATED CONDITIONS BELOW THAT LEVEL.
THIS SHOULD LIMIT THE CHANCE OF MEASURABLE RAIN/SHOWERS BUT DO
THINK THAT THE APPROACH OF THE COLD FRONT COULD HELP GENERATE SOME
DRIZZLE. WILL CARRY DRIZZLE IN THE GRIDS ACROSS ROUGHLY THE
EASTERN HALF OF THE FORECAST AREA LATE SATURDAY...AND THEN PUSH IT
EAST ON SUNDAY MORNING AS THE FRONT MOVES THROUGH. THE LOW
CLOUDS/STRATUS MAY LINGER IN THE EAST INTO THE AFTERNOON...BUT THE
WEST SHOULD HAVE CLOUDS DECREASING DURING THE MORNING.
TEMPERATURES WILL BE A BIT COOLER...AND WILL AIM FOR HIGHS IN THE
LOWER 50S.
MONDAY INTO TUESDAY COULD POTENTIALLY BE ACTIVE...HOWEVER THERE
HAS BEEN LITTLE CONSISTENCY AMONGST THE VARIOUS MEDIUM RANGE MODELS
DURING THAT PERIOD. DID NOT MAKE ANY LARGE SCALE CHANGES TO EARLY
NEXT WEEK...BUT SOME SOLUTIONS SHOW A POTENTIALLY WET PERIOD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
000
FXUS63 KLBF 200956
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
356 AM CST FRI NOV 20 2009
.SYNOPSIS..
WEAK TROF HAS PUSHED INTO FAR EASTERN NEBRASKA...WITH HIGH
PRESSURE BUILDING OVER THE CENTRAL ROCKIES. WATER VAPOR IMAGERY
HAS VERY DRY AIR OVER THE STATE WITH PACIFIC MOISTURE RIDING OVER
THE WESTERN CONUS RIDGE...INTO THE DAKOTAS. TEMPERATURES THIS
MORNING HAVE FALLEN INTO THE 20S.
&&
.DISCUSSION...
RIDGE WILL SHIFT EAST FOR TODAY AND TOMORROW AS TROF DIGS INTO THE
PACIFIC NW. HEIGHT RISES ARE SMALL AND 850 TEMPS RETURN TO VALUES
FROM A FEW DAYS AGO. GUIDANCE FOLLOWS SUIT AND HAVE HIGHS NEXT
COUPLE OF DAYS IN THE MID TO UPPER 50S...JUST ABOVE 10 DEGREES
WARMER THAN NORMAL.
NEXT WEAK IMPULSE TO MOVE ACROSS THE PLAINS SAT NIGHT. DRY
ATMOSPHERE FOR THE MOST PART...AND ONLY AN INCREASE OF CLOUDS
EXPECTED WITH THE FAST MOVING WAVE. TEMPS DOWN A FEW DEGREES
BEHIND THE FRONT...AROUND 50...WHICH IS STILL ABOVE NORMAL.
STRONGER FRONT TO QUICKLY MOVE ACROSS THE AREA SUNDAY NIGHT. SPEED
OF THIS SYSTEM STILL IN QUESTION...AS MODELS BEGIN TO DIVERGE ON
SOLUTIONS. IN GENERAL THE ENSEMBLE TRACK OF THE LOW REMAINS
NORTH...IN THE DAKOTAS. MOISTURE IS STILL LIMITED OVER THE
CWA...AND ONLY HAVE LOW POPS...ACROSS THE NORTH...CLOSER TO THE
LOW.
THEN MODEL CONSISTENCE DIVERGES GREATLY AS THE SHORTEN WORK WEEK
BEGINS. ECMWF HAS RETURN TO A FORECAST FROM A FEW DAYS AGO...OF
CLOSING OFF A LOW OVER THE WESTERN PLAINS MONDAY NIGHT INTO
TUESDAY. THIS SOLUTION WOULD RESULT IN A MAJOR WINTER STORM FOR
THE PLAINS...HOWEVER LITTLE SUPPORT BY THE OPERATIONAL GFS OR GFS
ENSEMBLE MODELS. THE OPERATIONAL GFS STILL PROMOTES AN OPEN
WAVE/CLIPPER SYSTEM MOVING ACROSS THE NORTHERN PLAINS. ECMWF DOES
HAVE SOME SUPPORT...A COUPLE OF THE GFS ENSEMBLE MODELS DO TAKE
THE LOW AND DIG IT FURTHER SOUTH ALTHOUGH NOT AS DEEP...WHERE AS
YESTERDAY ALL GFS ENSEMBLE MODELS HAD THE OPEN WAVE. HOWEVER
YESTERDAYS ECMWF WAS ALSO SHOWING AN OPEN WAVE SOLUTION. THUS
THIS SYSTEM WILL NEED MONITORED CLOSELY...ESPECIALLY AS EARLY
TRAVEL PLANS FOR THE THANKSGIVING HOLIDAY BEGIN.
&&
.AVIATION...
WITH A RIDGE ALOFT CONTINUING OVER THE WESTERN INTERMOUNTAIN
REGION...UNRESTRICTED CEILINGS AND VISIBILITY ARE LIKELY THROUGH
SATURDAY MORNING. THEREFORE...THE PRIMARY CONCERN FOR AIRPORT
OPERATIONS IS THE GRADUAL CHANGE IN WIND DIRECTION AND SPEED.
CURRENT INDICATIONS ARE THAT WIND IN CENTRAL AND SOUTHWEST NEBRASKA
WILL BE 10KT OR LOWER...BUT GRADUALLY SHIFTING AROUND TO THE SOUTH
BY LATE MORNING OR EARLY AFTERNOON. LOW LEVEL WIND PROFILES SHOW THE
SPEED INCREASING SIGNIFICANTLY AFTER SUNSET...BUT THE SURFACE
INVERSION IN THE PLATTE RIVER VALLEY WILL KEEP IT ABOVE THE SURFACE.
A SIMILAR SITUATION IS EXPECTED IN NORTHERN NEBRASKA...BUT THE
SURFACE INVERSION IS NOT EXPECTED TO BE WELL DEVELOPED AND WIND IN
VALENTINE IS LIKELY TO INCREASE THIS EVENING AND IS FORECAST TO BE
180 AT 10-15KT AND GUSTING TO NEAR 20KT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...MASEK
AVIATION...SPRINGER
000
FXUS63 KOAX 200939
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
339 AM CST FRI NOV 20 2009
.UPDATE...
UPDATED TO INCLUDE DENSE FOG ADVISORY THIS MORNING E/SE ZONES.
&&
.DISCUSSION...
APPEARS FOG WILL BE DENSE ENOUGH OVER A LARGE ENOUGH AREA TO
WARRANT A DENSE FOG ADVISORY THROUGH 15Z AND ONE WAS ISSUED BEFORE
FIRST ZONE ISSUANCE.
&&
.PREV DISCUSSION... /ISSUED 243 AM CST FRI NOV 20 2009/
DISCUSSION...
FORECAST CONCERNS INCLUDE HOW TO HANDLE MOISTURE RETURN IN SAT/SAT
NIGHT PERIOD...AND THEN MANAGING STRONGER TROUGH/PRECIPITATION
CHANCES IN MONDAY/TUESDAY PERIOD.
TODAY/TONIGHT...OVERNIGHT STLT WATER VAPOR IMAGERY SHOWED UPPER
TROUGH WITH DRYING BEHIND IT MOVING INTO ERN NEBR. SYSTEM WAS
PUSHING WEAK SFC TROUGH TOWARD MO RIVER AS OF 08Z. FOG DOESN/T
APPEAR AS DENSE BHND TROUGH WITH DWPTS DROPPING INTO THE LOWER/MID
20S...HOWEVER AREAS OF DENSE FOG WERE OCCURRING AND SHOULD CONT
TO OCCUR FOR A WHILE EAST OF IT. SINCE TROUGH WILL CONT TO WORK
EWD THIS MORNING...ALBEIT POSSIBLY WEAKENING...WILL HOLD OFF ON A
DENSE FOG ADVSRY ATTM BUT WL CONT TO MONITOR AFTER ISSUANCE.
OTHERWISE BASED ON EXPECTED MIXING/YDAS TEMPS WHERE MORE SUNSHINE
WAS PREVALENT WOULD THINK MOST AREAS SHOULD REACH MID 50S FOR
HIGHS. COULD SEE A LATE EVENING LOW TNGT BEFORE S/SE WINDS PICK UP
ENOUGH TO STEADY OR INCREASE TEMPS. TRIMMED BACK LOWS A BIT AND WL
ADJUST NON-DIURNALLY. DID NOT MENTION FOG ATTM BUT SOME IS
POSSIBLE. FORECAST SOUNDINGS FM NAM/GFS SUGGEST MOISTURE RETURN WL
BE MORE LIMITED SAT SO DROPPED MENTION OF AFTN SPRINKLES. TEMPS
COULD BE A DEG OR TWO WARMER THAN FRI.
SAT NGT/SUN...DEEPER MOISTURE SPREADS ACROSS MUCH OF THE CWA WHICH
COULD TIGHTEN DIURNAL TEMPERATURE RANGE BY KEEPING LOWS UP AND
HIGHS DOWN A BIT AND ADJUSTED SOME. ALSO MENTIONED DRIZZLE/FOG
WITH THIS INCREASE ALTHOUGH IT HAS BEEN A TENDENCY IN RECENT PAST
FOR MODELS TO OVER FCST THIS STUFF. KEPT IN SMALL POPS SERN ZONES
WHERE SOME MID LVL MOISTURE WAS FCST ALONG WITH MINOR FORCING.
MONDAY/TUESDAY...DRASTIC DIFFERENCES NOTED IN 00Z OPERATIONAL RUNS OF
GFS VS. GEM/ECMWF WITH LATTER TWO MODELS SLOWING DOWN AND CLOSING
OFF UPPER LOW POTENTIALLY PUTTING PARTS OF THE CWA IN THREAT MODE
FOR SIGNIFICANT PCPN. MEANWHILE GFS...ALTHOUGH FORECASTING DECENT
FORCING AND FAIRLY STEEP 700-500 MB LAPSE RATES MONDAY WAS MUCH
MORE PROGRESSIVE WITH SYSTEM WITH EVEN THE ERN CWA DRYING OUT BY
18Z TUE. BASED ON ECMWF/GEM AND THE FACT THAT THOSE MODELS WERE
SUPPORTED BY AT LEAST SEVERAL OF THE 00Z GFS ENSEMBLE MEMBERS
INCREASED POPS INTO THE 30-40 PERCENT ACROSS THE N IN MON NGT/TUE
PD AND ADJUSTED LOWS UP MON NGT AND HIGHS DOWN TUE.
NO CHANGES TO REST OF FCST...WED AND POSSIBLY THU COULD BE CHILLY
AND BLUSTERY...ESPECIALLY IF ECMWF/GEM VERIFY...BUT BOTH GFS AND
ECMWF WOULD SUGGEST SOME TEMPERATURE MODERATION BY WEEKS END.
AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
LIFR CIGS AND VSBY IN FOG WILL BE MAIN CONCERN AT KLNK AND KOMA
THROUGH 15Z...THEN BECOMING VFR FOR THE REMAINDER OF THE FORECAST
PERIOD.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR NEZ034-044-
045-051>053-066>068-088>093.
IA...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR IAZ043-055-
056-069-079-080-090-091.
&&
$$
CHERMOK/FOBERT
000
FXUS63 KGID 200932 CCA
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
308 AM CST FRI NOV 20 2009
.DISCUSSION...EARLY MORNING WATER VAPOR IMAGERY SHOWED A WAVE
MOVING ACROSS THE REGION...THOUGH A LACK OF MOISTURE WAS KEEPING
IT MAINLY CLEAR ACROSS THE FORECAST AREA. GENERALLY CLEAR SKIES
ARE EXPECTED TO PREVAIL MOST OF THE DAY...THOUGH THERE COULD BE A
FEW HIGH CLOUDS SPILLING INTO THE REGION AS AN UPPER RIDGE BUILDS
IN BEHIND THE PASSING WAVE. THERE COULD ALSO BE PATCHY FOG THIS
MORNING...ESPECIALLY IN THE EASTERN PORTION OF THE FORECAST AREA
WHERE WINDS ARE NEARLY CALM. TEMPERATURES WILL REMAIN CLOSE TO 10
DEGREES ABOVE NORMAL FOR TODAY WITH HIGHS EXPECTED TO BE IN THE
MID 50S. IT WILL REMAIN RELATIVELY QUIET AGAIN TONIGHT AS THE
UPPER RIDGE DOMINATES THE REGIONS WEATHER. THIS SHOULD KEEP SKIES
CLEAR TO AT MOST PARTLY CLOUDY. LOWS TONIGHT WILL BE IN THE MID
20S TO LOWER 30S.
THE NEXT UPPER WAVE BEGINS TO APPROACH ON SATURDAY...AND MOVES
ACROSS THE FORECAST AREA SATURDAY NIGHT INTO EARLY SUNDAY. THE
WAVE ALSO BRINGS A COLD FRONT ACROSS THE REGION...WITH BOTH THE
00Z NAM AND GFS SHOWING INCREASING LOW LEVEL MOISTURE AHEAD OF THE
FRONT. THERE COULD BE SOME INCREASE IN LOW CLOUDS ALREADY ON
SATURDAY AFTERNOON IN THE EASTERN PORTION OF THE FORECAST
AREA...BUT THE MAJORITY OF THE CLOUDS APPEAR TO HOLD OFF UNTIL
SATURDAY NIGHT WHEN MOST IF NOT ALL OF THE FORECAST AREA SHOULD
GET COVERED BY STRATUS. THE POSSIBILITY OF INCREASING LOW CLOUDS
IN THE EAST ON SATURDAY AFTERNOON COULD MAKE HIGHS A BIT
TRICKY...BUT FOR NOW WILL AGAIN GO WITH MID 50S OVER MOST OF THE
FORECAST AREA.
IT APPEARS THAT THERE COULD BE SOME DRIZZLE AND FOG AHEAD OF THE
FRONTAL BOUNDARY SATURDAY NIGHT INTO EARLY SUNDAY. FORECAST
SOUNDINGS FROM ACROSS THE FORECAST AREA SHOW VERY LIMITED MOISTURE
ABOVE H85...WITH NEARLY SATURATED CONDITIONS BELOW THAT LEVEL.
THIS SHOULD LIMIT THE CHANCE OF MEASURABLE RAIN/SHOWERS BUT DO
THINK THAT THE APPROACH OF THE COLD FRONT COULD HELP GENERATE SOME
DRIZZLE. WILL CARRY DRIZZLE IN THE GRIDS ACROSS ROUGHLY THE
EASTERN HALF OF THE FORECAST AREA LATE SATURDAY...AND THEN PUSH IT
EAST ON SUNDAY MORNING AS THE FRONT MOVES THROUGH. THE LOW
CLOUDS/STRATUS MAY LINGER IN THE EAST INTO THE AFTERNOON...BUT THE
WEST SHOULD HAVE CLOUDS DECREASING DURING THE MORNING.
TEMPERATURES WILL BE A BIT COOLER...AND WILL AIM FOR HIGHS IN THE
LOWER 50S.
MONDAY INTO TUESDAY COULD POTENTIALLY BE ACTIVE...HOWEVER THERE
HAS BEEN LITTLE CONSISTENCY AMONGST THE VARIOUS MEDIUM RANGE MODELS
DURING THAT PERIOD. DID NOT MAKE ANY LARGE SCALE CHANGES TO EARLY
NEXT WEEK...BUT SOME SOLUTIONS SHOW A POTENTIALLY WET PERIOD.
&&
.AVIATION...06Z TAF. VFR CONDITIONS ARE EXPECTED THROUGH THE TAF
PERIOD. LIGHT WEST TO NORTHWEST WINDS TONIGHT WILL BECOME FAIRLY
VARIABLE DURING THE DAY ON FRIDAY BEFORE TRANSITIONING TO THE
SOUTH FRIDAY NIGHT. IN GOOD RADIATIONAL CONDITIONS TONIGHT SOME
PATCHY FOG MAY DEVELOP AGAIN BUT ATTM DO NOT THINK VISIBILITIES
WILL BE RESTRICTED ENOUGH TO WARRANT A MENTION JUST YET.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
000
FXUS63 KGID 200908
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
308 AM CST FRI NOV 20 2009
.DISCUSSION...EARLY MORNING WATER VAPOR IMAGERY SHOWED A WAVE
MOVING ACROSS THE REGION...THOUGH A LACK OF MOISTURE WAS KEEPING
IT MAINLY CLEAR ACROSS THE FORECAST AREA. GENERALLY CLEAR SKIES
ARE EXPECTED TO PREVAIL MOST OF THE DAY...THOUGH THERE COULD BE A
FEW HIGH CLOUDS SPILLING INTO THE REGION AS AN UPPER RIDGE BUILDS
IN BEHIND THE PASSING WAVE. THERE COULD ALSO BE PATCHY FOG THIS
MORNING...ESPECIALLY IN THE EASTERN PORTION OF THE FORECAST AREA
WHERE WINDS ARE NEARLY CALM. TEMPERATURES WILL REMAIN CLOSE TO 10
DEGREES ABOVE NORMAL FOR TODAY WITH HIGHS EXPECTED TO BE IN THE
MID 50S. IT WILL REMAIN RELATIVELY QUIET AGAIN TONIGHT AS THE
UPPER RIDGE DOMINATES THE REGIONS WEATHER. THIS SHOULD KEEP SKIES
CLEAR TO AT MOST PARTLY CLOUDY. LOWS TONIGHT WILL BE IN THE MID
20S TO LOWER 30S.
THE NEXT UPPER WAVE BEGINS TO APPROACH ON SATURDAY...AND MOVES
ACROSS THE FORECAST AREA SATURDAY NIGHT INTO EARLY SUNDAY. THE
WAVE ALSO BRINGS A COLD FRONT ACROSS THE REGION...WITH BOTH THE
00Z NAM AND GFS SHOWING INCREASING LOW LEVEL MOISTURE AHEAD OF THE
FRONT. THERE COULD BE SOME INCREASE IN LOW CLOUDS ALREADY ON
SATURDAY AFTERNOON IN THE EASTERN PORTION OF THE FORECAST
AREA...BUT THE MAJORITY OF THE CLOUDS APPEAR TO HOLD OFF UNTIL
SATURDAY NIGHT WHEN MOST IF NOT ALL OF THE FORECAST AREA SHOULD
GET COVERED BY STRATUS. THE POSSIBILITY OF INCREASING LOW CLOUDS
IN THE EAST ON SATURDAY AFTERNOON COULD MAKE HIGHS A BIT
TRICKY...BUT FOR NOW WILL AGAIN GO WITH MID 50S OVER MOST OF THE
FORECAST AREA.
IT APPEARS THAT THERE COULD BE SOME DRIZZLE AND FOG AHEAD OF THE
FRONTAL BOUNDARY SATURDAY NIGHT INTO EARLY SUNDAY. FORECAST
SOUNDINGS FROM ACROSS THE FORECAST AREA SHOW VERY LIMITED MOISTURE
ABOVE H85...WITH NEARLY SATURDAY CONDITIONS BELOW THAT LEVEL.
THIS SHOULD LIMIT THE CHANCE OF MEASURABLE RAIN/SHOWERS BUT DO
THINK THAT THE APPROACH OF THE COLD FRONT COULD HELP GENERATE SOME
DRIZZLE. WILL CARRY DRIZZLE IN THE GRIDS ACROSS ROUGHLY THE
EASTERN HALF OF THE FORECAST AREA LATE SATURDAY...AND THEN PUSH IT
EAST ON SUNDAY MORNING AS THE FRONT MOVES THROUGH. THE LOW
CLOUDS/STRATUS MAY LINGER IN THE EAST INTO THE AFTERNOON...BUT THE
WEST SHOULD HAVE CLOUDS DECREASING DURING THE MORNING.
TEMPERATURES WILL BE A BIT COOLER...AND WILL AIM FOR HIGHS IN THE
LOWER 50S.
MONDAY INTO TUESDAY COULD POTENTIALLY BE ACTIVE...HOWEVER THERE
HAS BEEN LITTLE CONSISTENCY AMONGST THE VARIOUS MEDIUM RANGE MODELS
DURING THAT PERIOD. DID NOT MAKE ANY LARGE SCALE CHANGES TO EARLY
NEXT WEEK...BUT SOME SOLUTIONS SHOW A POTENTIALLY WET PERIOD.
&&
.AVIATION...06Z TAF. VFR CONDITIONS ARE EXPECTED THROUGH THE TAF
PERIOD. LIGHT WEST TO NORTHWEST WINDS TONIGHT WILL BECOME FAIRLY
VARIABLE DURING THE DAY ON FRIDAY BEFORE TRANSITIONING TO THE
SOUTH FRIDAY NIGHT. IN GOOD RADIATIONAL CONDITIONS TONIGHT SOME
PATCHY FOG MAY DEVELOP AGAIN BUT ATTM DO NOT THINK VISIBILITIES
WILL BE RESTRICTED ENOUGH TO WARRANT A MENTION JUST YET.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
000
FXUS63 KOAX 200843
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
243 AM CST FRI NOV 20 2009
.DISCUSSION...
FORECAST CONCERNS INCLUDE HOW TO HANDLE MOISTURE RETURN IN SAT/SAT
NIGHT PERIOD...AND THEN MANAGING STRONGER TROUGH/PRECIPITATION
CHANCES IN MONDAY/TUESDAY PERIOD.
TODAY/TONIGHT...OVERNIGHT STLT WATER VAPOR IMAGERY SHOWED UPPER
TROUGH WITH DRYING BEHIND IT MOVING INTO ERN NEBR. SYSTEM WAS
PUSHING WEAK SFC TROUGH TOWARD MO RIVER AS OF 08Z. FOG DOESN/T
APPEAR AS DENSE BHND TROUGH WITH DWPTS DROPPING INTO THE LOWER/MID
20S...HOWEVER AREAS OF DENSE FOG WERE OCCURRING AND SHOULD CONT
TO OCCUR FOR A WHILE EAST OF IT. SINCE TROUGH WILL CONT TO WORK
EWD THIS MORNING...ALBEIT POSSIBLY WEAKENING...WILL HOLD OFF ON A
DENSE FOG ADVSRY ATTM BUT WL CONT TO MONITOR AFTER ISSUANCE.
OTHERWISE BASED ON EXPECTED MIXING/YDAS TEMPS WHERE MORE SUNSHINE
WAS PREVALENT WOULD THINK MOST AREAS SHOULD REACH MID 50S FOR
HIGHS. COULD SEE A LATE EVENING LOW TNGT BEFORE S/SE WINDS PICK UP
ENOUGH TO STEADY OR INCREASE TEMPS. TRIMMED BACK LOWS A BIT AND WL
ADJUST NON-DIURNALLY. DID NOT MENTION FOG ATTM BUT SOME IS
POSSIBLE. FORECAST SOUNDINGS FM NAM/GFS SUGGEST MOISTURE RETURN WL
BE MORE LIMITED SAT SO DROPPED MENTION OF AFTN SPRINKLES. TEMPS
COULD BE A DEG OR TWO WARMER THAN FRI.
SAT NGT/SUN...DEEPER MOISTURE SPREADS ACROSS MUCH OF THE CWA WHICH
COULD TIGHTEN DIURNAL TEMPERATURE RANGE BY KEEPING LOWS UP AND
HIGHS DOWN A BIT AND ADJUSTED SOME. ALSO MENTIONED DRIZZLE/FOG
WITH THIS INCREASE ALTHOUGH IT HAS BEEN A TENDENCY IN RECENT PAST
FOR MODELS TO OVER FCST THIS STUFF. KEPT IN SMALL POPS SERN ZONES
WHERE SOME MID LVL MOISTURE WAS FCST ALONG WITH MINOR FORCING.
MONDAY/TUESDAY...DRASTIC DIFFERENCES NOTED IN 00Z OPERATIONAL RUNS OF
GFS VS. GEM/ECMWF WITH LATTER TWO MODELS SLOWING DOWN AND CLOSING
OFF UPPER LOW POTENTIALLY PUTTING PARTS OF THE CWA IN THREAT MODE
FOR SIGNIFICANT PCPN. MEANWHILE GFS...ALTHOUGH FORECASTING DECENT
FORCING AND FAIRLY STEEP 700-500 MB LAPSE RATES MONDAY WAS MUCH
MORE PROGRESSIVE WITH SYSTEM WITH EVEN THE ERN CWA DRYING OUT BY
18Z TUE. BASED ON ECMWF/GEM AND THE FACT THAT THOSE MODELS WERE
SUPPORTED BY AT LEAST SEVERAL OF THE 00Z GFS ENSEMBLE MEMBERS
INCREASED POPS INTO THE 30-40 PERCENT ACROSS THE N IN MON NGT/TUE
PD AND ADJUSTED LOWS UP MON NGT AND HIGHS DOWN TUE.
NO CHANGES TO REST OF FCST...WED AND POSSIBLY THU COULD BE CHILLY
AND BLUSTERY...ESPECIALLY IF ECMWF/GEM VERIFY...BUT BOTH GFS AND
ECMWF WOULD SUGGEST SOME TEMPERATURE MODERATION BY WEEKS END.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
LIFR CIGS AND VSBY IN FOG WILL BE MAIN CONCERN AT KLNK AND KOMA
THROUGH 15Z...THEN BECOMING VFR FOR THE REMAINDER OF THE FORECAST
PERIOD.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
CHERMOK/FOBERT
000
FXUS63 KGID 200520
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1120 PM CST THU NOV 19 2009
.AVIATION...06Z TAF. VFR CONDITIONS ARE EXPECTED THROUGH THE TAF
PERIOD. LIGHT WEST TO NORTHWEST WINDS TONIGHT WILL BECOME FAIRLY
VARIABLE DURING THE DAY ON FRIDAY BEFORE TRANSITIONING TO THE
SOUTH FRIDAY NIGHT. IN GOOD RADIATIONAL CONDITIONS TONIGHT SOME
PATCHY FOG MAY DEVELOP AGAIN BUT ATTM DO NOT THINK VISIBILITIES
WILL BE RESTRICTED ENOUGH TO WARRANT A MENTION JUST YET.
&&
PREV DISCUSSION... /ISSUED 338 PM CST THU NOV 19 2009/
SHORT TERM...TONIGHT THROUGH 12Z SATURDAY. NOT MUCH IN THE WAY
OF CHANGES FOR THE SHORT TERM PERIOD...THE QUIET CONTINUES. MAIN
UPPER LEVEL LOW PRESSURE SYSTEM CONTINUES TO GRADUALLY SHIFT EAST
AWAY FROM THE REGION...AND A SHORTWAVE TROUGH IS MAKING ITS WAY
ONTO THE NORTHERN PLAINS. AT THE SFC...IT WAS A FOGGY START TO THE
DAY FOR AREAS ALONG AND EAST OF 281 WHERE WINDS WERE CALM AND
SKIES WERE CLEAR. THE FRONTAL BOUNDARY WHICH STARTED THE DAY
ACROSS WESTERN NEB HAS MADE VERY LITTLE PROGRESS EAST...WITH MOST
OF THE CWA STILL UNDER THE INFLUENCE OF LIGHT SOUTHERLY/VARIABLE
WINDS. FAR WESTERN PORTIONS OF THE CWA HAVE SEEN A WNW SWITCH TO
WINDS...AND TEMPS HAVE BEEN SLIGHTLY LOWER...HANGING AROUND THE 50
DEGREE MARK...WITH CENTRAL AND EASTERN AREAS IN THE LOWER/MID 50S.
EVENTUALLY THIS SFC FRONTAL BOUNDARY WILL SHIFT EAST THROUGH THE
AREA...PUSHED BY THE APPROACHING UPPER LEVEL SHORTWAVE TROUGH. NO
PRECIPITATION IS EXPECTED...MOISTURE AVAILABILITY JUST NOT THERE.
AFTER THE FOGGY START THIS MORNING AM A LITTLE CONCERNED ABOUT THE
POTENTIAL TONIGHT...MAINLY ACROSS THE FAR EASTERN AREAS...BUT KEPT
MENTION OUT AS AM EXPECTING WINDS TO BECOME WNW AND DRIER AIR TO
BUILD IN ACROSS THE ENTIRE CWA OVERNIGHT...KEEPING BEST CHANCES FOR
FOG JUST OFF TO THE EAST.
SATURDAY FORECAST REMAINS DRY...WITH THE CWA SITTING UNDER WEAK
UPPER LEVEL SHORTWAVE RIDGING BEHIND THE DEPARTING TROUGH. AT THE
SFC...BEHIND THE FRONT...WEAK HIGH PRESSURE WILL SETTLE IN ACROSS
THE REGION...BRINGING ANOTHER DAY WITH LIGHT AND GENERALLY VARIABLE
WINDS. EXPECTING ANOTHER DAY WITH PLENTY OF SUNSHINE...WITH
AFTERNOON HIGH TEMPERATURES REACHING UP ONCE AGAIN INTO THE LOWER TO
MID 50S.
LONG TERM...SATURDAY THROUGH THANKSGIVING DAY. THE MAIN ISSUE IS
THE DEVELOPMENT OF AN UPPER LOW IN THE AREA EARLY NEXT WEEK...AND
JUST HOW MUCH IMPACT IT WILL HAVE.
THE PATTERN IS ACTIVE THROUGH THIS PERIOD. SATURDAY STARTS THINGS
OFF MILD FOR LATE NOVEMBER...ALTHOUGH A FAIRLY DECENT SOUTH BREEZE
WILL KICK IN BY MIDDAY...LIKELY GUSTING OVER 20 MPH. AT LEAST
TEMPERATURES WILL BE IN THE 50S. THE MODELS ARE IN GOOD AGREEMENT
THAT A SURGE OF LOW LEVEL MOISTURE WILL INFILTRATE THE AREA SATURDAY
NIGHT AHEAD OF AN APPROACHING WEAK FRONT. SIMILAR TO A FRONTAL
PASSAGE LAST WEEK...THE SPREAD OF LOW CLOUDS LOOKS TO OCCUR...AND AN
UPPER LEVEL WAVE WILL PROBABLY BE ENOUGH TO TRIP SOME SHOWERS.
CONTINUED WITH SMALL PRECIPITATION CHANCE FOR NOW...REMAINING AS
LIQUID...BUT THAT MAY NEED TO INCREASE SOME WITH TIME.
THIS FORECASTER DOESN/T HAVE A GOOD HANDLE ON RUN-TO-RUN TRENDS
WITH THIS FORECAST AT THIS POINT...SO WAS LEARY TO CHANGE MUCH FOR
THE FIRST OF NEXT WEEK. RIGHT NOW...TRENDS SUPPORT THE UPPER LEVEL
SYSTEM ENDING UP IN IOWA BY TUESDAY NIGHT. HOW IT GETS THERE IS
STILL UNCERTAIN...BUT IT APPEARS IT WILL DIG DOWN FROM THE NORTHWEST
AND DEEPEN JUST TO OUR EAST. MODELS CONTINUE TO KEEP MOST OF THE MAIN
PRECIPITATION AREA TO OUR EAST...SO THE LOWER PRECIPITATION CHANCES
REMAIN FOR NOW. MOST RECENT RUNS...SUGGEST COLDER TEMPERATURES ARE
MORE LIKELY...WITH MIDDLE 40S AT BEST AND BRISK WINDS SETTING UP ON
TUESDAY. TREND OF TEMPERATURES MAY HAVE TO GO LOWER WITH TIME.
THAT COOLER TREND IDEA LOOKS LIKE IT WILL HANGOVER INTO THANKSGIVING
DAY...YET STILL REASONABLY SEASONAL TEMPERATURES SHOULD BE
ANTICIPATED. IT APPEARS AT LEAST FIRST PART OF THE HOLIDAY WEEKEND
SHOULD BE DRY...ALTHOUGH THE PATTERN IS CHANGEABLE. THIS CURRENT
STRETCH OF 3 TO 5 DAYS OF PLEASANT WEATHER IS LIKELY MORE THE
ANOMALY THAN THE NORM.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
000
FXUS63 KGID 192341
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
541 PM CST THU NOV 19 2009
.AVIATION...00Z KGRI TAF. VFR SKY AND VISIBILITY CONDITIONS ALONG
WITH LIGHT WINDS WILL MAKE FOR A QUIET PERIOD. A SURFACE FRONT
CURRENTLY DRAPED ACROSS CENTRAL NEBRASKA...WITH SOUTHERLY WINDS
OUT AHEAD AT THE GRI TERMINAL WILL SLOWLY SLIDE EAST TONIGHT. THIS
WILL BRING WEST AND EVENTUALLY NORTHWEST WINDS TO KGRI...BUT
SPEEDS ARE EXPECTED TO REMAIN BELOW 10KTS.
&&
.PREV DISCUSSION... /ISSUED 338 PM CST THU NOV 19 2009/
SHORT TERM...TONIGHT THROUGH 12Z SATURDAY. NOT MUCH IN THE WAY
OF CHANGES FOR THE SHORT TERM PERIOD...THE QUIET CONTINUES. MAIN
UPPER LEVEL LOW PRESSURE SYSTEM CONTINUES TO GRADUALLY SHIFT EAST
AWAY FROM THE REGION...AND A SHORTWAVE TROUGH IS MAKING ITS WAY
ONTO THE NORTHERN PLAINS. AT THE SFC...IT WAS A FOGGY START TO THE
DAY FOR AREAS ALONG AND EAST OF 281 WHERE WINDS WERE CALM AND
SKIES WERE CLEAR. THE FRONTAL BOUNDARY WHICH STARTED THE DAY
ACROSS WESTERN NEB HAS MADE VERY LITTLE PROGRESS EAST...WITH MOST
OF THE CWA STILL UNDER THE INFLUENCE OF LIGHT SOUTHERLY/VARIABLE
WINDS. FAR WESTERN PORTIONS OF THE CWA HAVE SEEN A WNW SWITCH TO
WINDS...AND TEMPS HAVE BEEN SLIGHTLY LOWER...HANGING AROUND THE 50
DEGREE MARK...WITH CENTRAL AND EASTERN AREAS IN THE LOWER/MID 50S.
EVENTUALLY THIS SFC FRONTAL BOUNDARY WILL SHIFT EAST THROUGH THE
AREA...PUSHED BY THE APPROACHING UPPER LEVEL SHORTWAVE TROUGH. NO
PRECIPITATION IS EXPECTED...MOISTURE AVAILABILITY JUST NOT THERE.
AFTER THE FOGGY START THIS MORNING AM A LITTLE CONCERNED ABOUT THE
POTENTIAL TONIGHT...MAINLY ACROSS THE FAR EASTERN AREAS...BUT KEPT
MENTION OUT AS AM EXPECTING WINDS TO BECOME WNW AND DRIER AIR TO
BUILD IN ACROSS THE ENTIRE CWA OVERNIGHT...KEEPING BEST CHANCES FOR
FOG JUST OFF TO THE EAST.
SATURDAY FORECAST REMAINS DRY...WITH THE CWA SITTING UNDER WEAK
UPPER LEVEL SHORTWAVE RIDGING BEHIND THE DEPARTING TROUGH. AT THE
SFC...BEHIND THE FRONT...WEAK HIGH PRESSURE WILL SETTLE IN ACROSS
THE REGION...BRINGING ANOTHER DAY WITH LIGHT AND GENERALLY VARIABLE
WINDS. EXPECTING ANOTHER DAY WITH PLENTY OF SUNSHINE...WITH
AFTERNOON HIGH TEMPERATURES REACHING UP ONCE AGAIN INTO THE LOWER TO
MID 50S.
LONG TERM...SATURDAY THROUGH THANKSGIVING DAY. THE MAIN ISSUE IS
THE DEVELOPMENT OF AN UPPER LOW IN THE AREA EARLY NEXT WEEK...AND
JUST HOW MUCH IMPACT IT WILL HAVE.
THE PATTERN IS ACTIVE THROUGH THIS PERIOD. SATURDAY STARTS THINGS
OFF MILD FOR LATE NOVEMBER...ALTHOUGH A FAIRLY DECENT SOUTH BREEZE
WILL KICK IN BY MIDDAY...LIKELY GUSTING OVER 20 MPH. AT LEAST
TEMPERATURES WILL BE IN THE 50S. THE MODELS ARE IN GOOD AGREEMENT
THAT A SURGE OF LOW LEVEL MOISTURE WILL INFILTRATE THE AREA SATURDAY
NIGHT AHEAD OF AN APPROACHING WEAK FRONT. SIMILAR TO A FRONTAL
PASSAGE LAST WEEK...THE SPREAD OF LOW CLOUDS LOOKS TO OCCUR...AND AN
UPPER LEVEL WAVE WILL PROBABLY BE ENOUGH TO TRIP SOME SHOWERS.
CONTINUED WITH SMALL PRECIPITATION CHANCE FOR NOW...REMAINING AS
LIQUID...BUT THAT MAY NEED TO INCREASE SOME WITH TIME.
THIS FORECASTER DOESN/T HAVE A GOOD HANDLE ON RUN-TO-RUN TRENDS
WITH THIS FORECAST AT THIS POINT...SO WAS LEARY TO CHANGE MUCH FOR
THE FIRST OF NEXT WEEK. RIGHT NOW...TRENDS SUPPORT THE UPPER LEVEL
SYSTEM ENDING UP IN IOWA BY TUESDAY NIGHT. HOW IT GETS THERE IS
STILL UNCERTAIN...BUT IT APPEARS IT WILL DIG DOWN FROM THE NORTHWEST
AND DEEPEN JUST TO OUR EAST. MODELS CONTINUE TO KEEP MOST OF THE MAIN
PRECIPITATION AREA TO OUR EAST...SO THE LOWER PRECIPITATION CHANCES
REMAIN FOR NOW. MOST RECENT RUNS...SUGGEST COLDER TEMPERATURES ARE
MORE LIKELY...WITH MIDDLE 40S AT BEST AND BRISK WINDS SETTING UP ON
TUESDAY. TREND OF TEMPERATURES MAY HAVE TO GO LOWER WITH TIME.
THAT COOLER TREND IDEA LOOKS LIKE IT WILL HANGOVER INTO THANKSGIVING
DAY...YET STILL REASONABLY SEASONAL TEMPERATURES SHOULD BE
ANTICIPATED. IT APPEARS AT LEAST FIRST PART OF THE HOLIDAY WEEKEND
SHOULD BE DRY...ALTHOUGH THE PATTERN IS CHANGEABLE. THIS CURRENT
STRETCH OF 3 TO 5 DAYS OF PLEASANT WEATHER IS LIKELY MORE THE
ANOMALY THAN THE NORM.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
| 
