FXUS63 KOAX 092053
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
253 PM CST TUE NOV 9 2010
.SHORT TERM...TONIGHT THROUGH FRIDAY.
PRECIPITATION CHANCES WEDNESDAY...THEN THURSDAY INTO FRIDAY ARE
THE PRIMARY FORECAST CONCERNS.
MAIN WEATHER MAKER FOR LATER THIS WEEK WAS SEEN ON WATER VAPOR
IMAGERY TODAY DIVING INTO THE PACIFIC NORTHWEST. THIS UPPER
LOW/TROUGH IS FORECAST TO KICK CURRENT TROUGH IN THE ROCKIES THROUGH
THE PLAINS ON WEDNESDAY. GIVEN AMPLITUDE OF TROUGH IN THE ROCKIES
AND RIDGE TO OUR EAST EXPECT THIS TROUGH TO RIDE NORTH-NORTHEAST
THROUGH CENTRAL NEBRASKA INTO THE NORTHERN PLAINS WEDNESDAY
AFTERNOON. THIS TRACK SHOULD FOCUS ANY PRECIPITATION CHANCES OVER
OUR WEST AND NORTH CWA ON WEDNESDAY. THIS SYSTEM WILL ALSO DRIVE A
COLD FRONT THROUGH THE CWA BY WEDNESDAY AFTERNOON. SOUTH WINDS
AHEAD OF THAT FRONT WERE DRAWING LOW LEVEL MOISTURE INTO EASTERN
NEBRASKA AND SOUTHWEST IOWA...WITH DEW POINTS THIS AFTERNOON
ALREADY IN THE MID TO UPPER 40S. WITH SOUTH WINDS CONTINUING
OVERNIGHT...RATHER MILD LOWS IN THE MID AND UPPER 40S WILL BE
COMMON.
CLOUDS SHOULD ALSO INCREASE AS WING OF LOW/MID LEVEL WARM
ADVECTION AHEAD OF APPROACHING TROUGH INDUCES LIFT OVER MUCH OF
THE CWA. FORECAST SOUNDINGS POINT TO BROKEN TO OVERCAST CONDITIONS
SHORTLY AFTER MIDNIGHT AS LOW CLOUDS DEVELOP. SOUNDINGS ALSO
SUGGEST PATCHY DRIZZLE IS POSSIBLE AS BOUNDARY LAYER SATURATES
UNDER WARM ADVECTION REGIME.
AS TROUGH LIFTS NORTH DURING THE MORNING...MOISTURE AND LIFT IN
CURVED MID LEVEL JET ENTRANCE REGION SHOULD SPARK SHOWERS OVER
NORTHERN CWA...WHICH CONTINUES INTO THE AFTERNOON. IF SHOWERS BEGIN
EARLY ENOUGH...A FEW FLAKES MAY MIX WITH THE RAIN...BUT EXPECT BULK
OF PRECIPITATION TO OCCUR WHEN LOW LEVEL TEMPERATURE PROFILE IS WARM
ENOUGH FOR RAIN. TROUGH WILL ALSO NUDGE SURFACE FRONT THROUGH THE
CWA BY EARLY AFTERNOON. WESTERLY LOW LEVEL FLOW WILL HELP TO SCOUR
OUT CLOUDS IN OUR SOUTH...ALLOWING TEMPERATURES TO APPROACH 60.
COOLER HIGHS NEAR OR BELOW 50 ARE EXPECTED IN THE NORTH WHERE CLOUDS
AND THERMAL TROUGH WILL EXIST.
WEDNESDAY NIGHT WILL BE DRY WITH DECREASING CLOUDS AS WE WAIT FOR
THURSDAY/FRIDAY SYSTEM TO EJECT INTO THE PLAINS. HAVE LOWS IN THE
UPPER 20S TO MID 30S.
LOW LEVEL FLOW WILL BECOME EAST AND NORTHEAST THROUGH TIME ON
THURSDAY AS SURFACE CYCLOGENESIS COMMENCES TO OUR SOUTHWEST AHEAD
OF UPPER LOW. INCREASE IN MID/HIGH CLOUDS WILL HOLD TEMPS TO THE
LOWER 50S MOST SPOTS. AS SURFACE LOW MOVES CLOSER THURSDAY
AFTERNOON...INCREASING BAROCLINICITY FROM WESTERN KANSAS INTO OUR
SOUTHERN CWA WILL SET THE STAGE FOR POTENTIALLY SIGNIFICANT
ISENTROPIC UPGLIDE ACROSS MUCH OF THE CWA. MODELS HAVE SLOWED
ONSET OF PRECIPITATION FROM EARLIER RUNS...AND NOW EXPECT RAIN TO
BEGIN IN OUR SOUTHWEST THURSDAY AFTERNOON. MOST ALL OF THE CWA
WILL SEE RAIN THURSDAY NIGHT WITH POTENTIALLY HEAVY RAIN IN OUR
SOUTH NEAR 850 FRONTAL BOUNDARY. HAVE INCREASED POPS FROM GOING
FORECAST TO CATEGORICAL ALL BUT NORTHERN HALF. TEMPERATURE
PROFILES ON FORECAST SOUNDINGS STILL SHOW A SNOW OR RAIN/SNOW MIX
IN OUR NORTHERN THIRD TOWARD AND AFTER MIDNIGHT. NOT EXPECTING
ACCUMULATION GIVEN WARMTH OF BOUNDARY LAYER...BUT MAY HAVE TO
EXAMINE FURTHER WITH LATER RUNS.
STILL A GOOD CHANCE FOR RAIN IN OUR SOUTHEAST FRIDAY MORNING WITH
PRECIPITATION ENDING FROM WEST TO EAST DURING THE DAY. LINGERING
CLOUDS AND NORTH WINDS ALONG WITH COLD ADVECTION SHOULD KEEP HIGHS
ONLY IN THE 40S.
DERGAN
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY.
EXTENDED PERIOD STARTS OUT WITH ONE SYSTEM LIFTING NORTHEAST OUT OF
THE REGION TOWARDS THE GREAT LAKES WHILE A SECOND WAVE BEGINS TO
DROP INTO THE NORTHERN ROCKIES. BOTH THE GFS AND ECMWF FAIRLY
SIMILAR IN DROPPING THE SECOND WAVE SOUTH THROUGH SUNDAY ALTHOUGH
GFS IS MORE TO THE EAST OVER THE SOUTHERN ROCKIES WITH ITS POSITION.
AFTER THAT MODELS BEGIN TO DIFFER A BIT MORE AS GFS PHASES A
NORTHERN WAVE WITH THE SOUTHERN OVER THE CENTRAL CONUS BY THE END OF
THE PERIOD WHILE THE ECMWF TENDS TO KEEP THE TWO FLOWS SEPARATE.
RESULT IS A SOMEWHAT BETTER CHANCE OF PRECIP WITH THE GFS THAN ECMWF.
NEW 12Z EURO HOWEVER MAINTAINS THIS TREND SO FOR NOW HAVE STAYED
WITH A DRY FORECAST FOR THIS TIME FRAME. MORE SEASONAL TEMPERATURES
INDICATED AS TROUGHING SETS UP. ANOTHER STRONG WAVE APPROACHES THE
NORTHERN PLAINS AT THE END OF THE EXTENDED WITH EURO SHOWING
POTENTIAL FOR SIGNIFICANTLY COLDER AIR BY LATE IN THE UPCOMING
WEEK.
FOBERT
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
BRISK SOUTHEAST WINDS AROUND 15-20KT GUSTING AROUND 25KT WILL
CONTINUE THRU 00Z THEN DECREASE TO 12KT OR LESS TONIGHT. ALTHOUGH
THE SFC WINDS WILL DECREASE...DID INCLUDE LLWS AT OMA/LNK AFT 00Z.
VFR CONDITIONS WILL CONTINUE WITH BKN HIGH CLOUDS THRU 09Z. AFTER
09Z...THE COMBINATION OF AN H5 TROF AND A SFC FNT IN THE AREA WILL
RESULT IN THICKENING CLDS AND SFC WINDS SHIFTING TO THE NORTHWEST.
MVFR CIGS AND VSBYS ARE EXPECTED TO DEVELOP AFT 12Z FOR WEDNESDAY
MORNING.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$