000
FXUS63 KOAX 032102
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
302 PM CST WED DEC 3 2008
.SHORT TERM...TONIGHT THROUGH SATURDAY
TEMPERATURES ARE THE PRIMARY FORECAST CONCERN THROUGH SATURDAY.
SNOW THAT ENDED THIS MORNING FELL PRETTY MUCH WHERE EXPECTED...BUT
AMOUNTS WERE ABOUT HALF OF FORECAST VALUES FROM YESTERDAY. NORTHEAST
NEBRASKA FROM ABOUT NORFOLK NORTH HAD ABOUT AN INCH...AS WELL AS A
BAND FROM JUST SOUTH OF OMAHA AND LINCOLN INTO SOUTHWESTERN IOWA
WHERE AMOUNTS AGAIN AROUND AN INCH WERE NOTED. THE REST OF THE AREA
HAD LESS THAN AN INCH...AND BY THIS AFTERNOON ONLY TRACE AMOUNTS
WERE LEFT...ESPECIALLY NORTH OF INTERSTATE 80 AND IN SOUTHEAST
NEBRASKA WEST OF THE FALLS CITY AND AUBURN AREAS. SO TEMPERATURE
FORECASTS WILL BE AFFECTED ONLY IN SMALL AREAS OF THE CWA THROUGH
THE NEXT SEVERAL DAYS...WITH LOWS MOST DIFFICULT TO NAIL DOWN OVER
THE SNOW COVER.
NORTHWEST WINDS HAVE CONTINUED BEHIND EXITING SHORT WAVE/COLD FRONT.
AND DESPITE LOTS OF SUN THIS AFTERNOON...TEMPERATURES WERE ONLY IN
THE MID AND UPPER 20S AS OF 2PM. SOME STRATO CU WAS NOTED FORMING
OFF THE SNOW FIELDS OF SOUTH DAKOTA...BUT EXPECT THESE TO DISSIPATE
WITH SUNSET. WINDS SHOULD ALSO DIE DOWN A BIT DURING THE EVENING AS
HIGH PRESSURE BRUSHES THE AREA TO OUR WEST. CLEAR SKIES AND LIGHT
WINDS WILL ALLOW HEAT TO RADIATE OUT QUICKLY THIS EVENING BEFORE
WINDS KICK UP AGAIN BEHIND SECONDARY COLD FRONT/TROUGH DROPPING
SOUTHEAST. WILL ALSO PICK UP MID AND HIGH LEVEL MOISTURE FROM JET
STREAK DROPPING INTO THE PLAINS AND EXPANDING WARM ADVECTION SHIELD
TO OUR SOUTHWEST. LOWS IN THE TEENS ARE LIKELY EVERYWHERE...BUT
COULD SEE SOME SINGLE DIGITS NORTH AND SOUTHEAST.
COLD START TO THE DAY...VARIABLE CLOUDS...AND COLD ADVECTION WILL
KEEP TEMPERATURES FROM REBOUNDING MUCH ON THURSDAY. 850 TEMPS
ACTUALLY DROP A COUPLE OF DEGREES FROM 12Z TO 00Z. HAVE TRIMMED
HIGHS INTO THE MID AND UPPER 20S...BUT COULD SEE EVEN COOLER TEMPS
IF LOWS DROP MORE THAN EXPECTED TONIGHT.
EXPECT A LITTLE WARMUP BY FRIDAY AS SURFACE WINDS TURN TO THE
SOUTHWEST AHEAD OF ANOTHER POTENT SHORT WAVE DROPPING SOUTH OUT OF
CANADA. LOWS THURSDAY NIGHT COULD OCCUR IN THE EVENING UNDER DECENT
RADIATIONAL COOLING REGIME BEFORE SOUTHWEST FLOW KICKS UP AFTER
MIDNIGHT. 850 TEMPS WARM TO NEAR -5C FRIDAY AFTERNOON...SIGNALING A
DECENT WARMING TREND...HOWEVER INCREASING HIGH LEVEL CLOUDS WILL DAMPEN
THAT AFFECT. HAVE HIGHS JUST BELOW MOS NUMBERS...BUT MID TO UPPER
30S WILL FEEL MUCH WARMER THAN 20S HIGHS FROM THURSDAY.
ATTENDANT COLD FRONT WILL SWING THROUGH THE CWA FRIDAY NIGHT AS
SHORT WAVE PLUNGES INTO THE GREAT LAKES. MOISTURE WITH THE FRONT
WILL BE LIMITED DUE TO NORTHERLY SOURCE REGION...BUT WILL LIKELY
SQUEEZE OUT AT LEAST SOME SNOW. GFS/NAM MID LEVEL Q-VECTOR
CONVERGENCE AND MODERATE ISENTROPIC UPGLIDE ALONG 295K SURFACE
SUGGEST A HALF INCH TO AN INCH OF SNOW IS POSSIBLE OVER FAR
EASTERN NEBRASKA AND SOUTHWEST IOWA. HAVE ADDED LOW POPS TO MUCH
OF THE CWA FRIDAY NIGHT WITH THIS FRONTAL PASSAGE DESPITE SCANT
QPF FROM GFS/NAM. ANY LINGERING SNOW SATURDAY MORNING WILL QUICKLY
EXIT THE AREA...LEAVING ANOTHER COLD AND BLUSTERY DAY WITH
NORTHWEST WINDS AND COLD ADVECTION DOMINATING THE AFTERNOON. HAVE
HIGHS IN THE LOWER 30S...WHICH IS ONLY ABOUT 5-8 DEGREES WARMER
THAN RELATIVELY MILD MORNING LOWS IN THE 20S.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY.
MEDIUM RANGE MODELS AS WELL AS ENSEMBLES CONTINUE TO ADVERTISE LARGE
SCALE UPPER LEVEL TROF ESTABLISHED OVER THE EASTERN CONUS THROUGH EH
PERIOD WITH A SERIES OF SHORTWAVE TROFS RIDING UP AND OVER THE
EASTERN PACIFIC RIDGE AND EVENTUALLY EJECTING INTO THE PLAINS. AS
USUAL...TIMING/AMPLITUDE DIFFERENCES BETWEEN ECM AND GFS AFFECTING
SURFACE CYCLOGENESIS PROGS AND ASSOCIATED IMPACT OF COLD AIR
INTRUSIONS TO THE REGION. WILL LEAN MORE TOWARDS MORE CONSISTENT ECM
SOLUTION WITH BLEND OF GEM. AT THIS POINT IT LOOKS LIKE THE FIRST
CHANCE FOR PCPN COMES EARLY SUNDAY MORNING OVER THE NRN CWA VIA
STOUT ISENTROPIC UPGLIDE ALONG 290K-295K SFC. BUFKIT/COBB DATA
SUGGESTING AIR COLUMN UP NORTH SHOULD BE COLD ENOUGH FOR -SN EARLY
ON. MIX OF SLEET/SN THEN LOOKS POSSIBLE IN THE AFTERNOON AND INTO
SUNDAY NIGHT. NEVERTHELESS...ANY AMOUNTS SHOULD BE ON THE LIGHT SIDE
DUE TO WEAK MOIST AVAILABILITY. APPROACHING WESTERN SHORTWAVE ENERGY
SUNDAY NIGHT EVENTUALLY INDUCES SFC CYCLOGENESIS INVOF SD WITH
ATTENDANT COLD FRONT SWEEPING THROUGH THE CWA BY MONDAY AFTERNOON.
LOW CONFIDENCE AT THIS POINT WRT TIMING OF FRONT AND INFLUX OF LOW
LEVEL MOISTURE...AND WILL THEREFORE OPT FOR SMALL POPS INTO MONDAY
NIGHT. OTHERWISE WILL LEAVE TUESDAY AND WEDNESDAY DRY FOR NOW WITH
LITTLE MODEL AGREEMENT SHOWN. IF GFS VERIFIES THOUGH...WOULD SEE
COLDER TEMPS THAN GOING 30S FOR DAYS 6 AND 7.
&&
.AVIATION...
FOR TAF SITES KOFK/KOMA/KLNK THROUGH 04/18Z.
SFC HIGH PRES IS ALREADY BEGINNING TO DECREASE THE PRESSURE
GRADIENT. EXPECT THIS TREND TO CONTINUE WITH LIGHT WEST WINDS AFT
00Z. AFT 04Z...A REINFORCING CDFNT WILL BRING SOME CLDS AND
FLURRIES TO NORTHEAST NEBRASKA...THIS COULD AFFECT BOTH KOFK AND
KOMA...HOWEVER JUST MENTIONED VFR CIGS WITH FLURRIES AT KOFK AFT 04Z
AND WILL NEED TO MONITOR CLDS/-SN SHOULD THEY HOLD ON LONGER INTO
THURSDAY. NW WINDS WILL INCREASE MORESE AT KOFK BEHIND THE FNT FM
10-15KT AND LATER IN THE MORNING AT KOMA/KLNK.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DERGAN
LONG TERM...DEE
AVIATION...ZAPOTOCNY
