FXUS63 KOAX 260137 AAA
AFDOAX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
737 PM CST WED NOV 25 2009

.UPDATE...
UPDATED FOR LINGERING CLOUD COVER THIS EVENING.

&&

.DISCUSSION...
MADE A SLIGHT ADJUSTMENT TO CLOUD COVER...MAINLY THIS EVENING.
00-0115Z STLT IMAGERY SHOWED STRATOCUMULUS WERE BEGINNING TO
QUICKLY BREAK UP...BUT SOME AREAS IN ERN NEBR WILL HOLD ON A BIT
LONGER THAN PREV FCST AND MADE MINOR CHANGES. WITH DRY AIR IN
PLACE OR ADVECTING IN...DID NOT CHANGE LOW TEMPERATURE
FORECAST. HOWEVER...DID ADJUST HOURLIES A BIT TO FIT CLOUD
COVER/CURRENT TRENDS.

CHERMOK

&&

.PREV DISCUSSION... /ISSUED 300 PM CST WED NOV 25 2009/ 

SHORT TERM...TONIGHT THROUGH SATURDAY.
THE CLOSED MID TROPOSPHERIC LOW SHOWN IN WATER VAPOR IMAGERY LOOP
OVER IOWA SHOULD CONTINUE TO MOVE OFF TO THE SOUTHEAST TONIGHT.
COULD SEE SOME FLURRIES IN WESTERN IOWA AND EXTREME EASTERN
NEBRASKA THIS EVENING. OTHERWISE...WIND WILL DIMINISH AS THE
PRESSURE GRADIENT DECREASES. MID LEVEL HEIGHTS WILL INCREASE
TONIGHT THROUGH THANKSGIVING DAY AS RIDGE OVER THE WESTERN U.S.
BUILDS EAST INTO THE PLAINS THROUGH FRIDAY. AFTER EARLY TONIGHT...
EXPECT MAINLY DRY CONDITIONS THROUGH SATURDAY. TEMPERATURES WILL
PROVIDE THE MAIN FORECAST CHALLENGES. FOR TONIGHT...EXPECT DECENT
RADIATIONAL COOLING AND HAVE LOWS MAINLY IN THE LOWER AND MID 20S.
LOW LEVEL TEMPERATURES START TO MODERATE...BUT WITH A COLD START
THURSDAY MORNING AND ONLY FAIR MIXING IN THE AFTERNOON WE WILL
PROBABLY ONLY SEE HIGHS IN THE 40S. WARM ADVECTION INCREASES
THURSDAY NIGHT...AND FOR NOW HAVE LOWS IN THE MID OR UPPER 20S.

FRIDAY WILL PROBABLY BE THE MILDEST DAY...AS A WARM FRONT PUSHES
EASTWARD ACROSS THE PLAINS. THE 12Z GFS AND 12Z NAM BOTH INDICATED
850 MB TEMPERATURES BETWEEN 10 AND 15 DEGREES C FRIDAY. DID NOT 
WANT TO GET TOO OPTIMISTIC...SO WENT WITH HIGHS MOSTLY 55 TO 60...
WITH SOME LOWER 60S POSSIBLE IN THE WESTERN PART OF THE FORECAST
AREA. COOLER AIR SHOULD MOVE INTO THE AREA BEHIND THE NEXT FRONT
THAT WILL DROP DOWN ACROSS THE AREA SATURDAY.

LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY.
THE LONG TERM PERIOD WILL BEGIN WITH A COOLING TREND THAT WILL BE
BRIEFLY INTERRUPTED BEFORE BEING REINFORCED BY THE MIDDLE OF NEXT
WEEK. GFS AND ECMWF ARE IN FAIRLY GOOD AGREEMENT WITH OVERALL
WEATHER PATTERN THROUGH WEDNESDAY...SO RELATIVELY HIGHER
CONFIDENCE EXISTS TODAY THAN IN PAST FEW RUNS.

LARGE SCALE PATTERN BEGINS SATURDAY NIGHT WITH A TROUGH EXTENDING 
FROM THE NORTHERN PLAINS INTO THE SOUTHWEST U.S. THE FLOW SPLITS 
SUNDAY WITH NORTHERN WAVE DROPPING INTO THE WESTERN GREAT 
LAKES...WHICH DRIVES COLD FRONT THROUGH THE CWA. MEANWHILE SOUTHERN 
LOW PROGRESSES EAST INTO THE SOUTHERN PLAINS DURING THE FIRST HALF 
OF THE WEEK...AND ANOTHER NORTHERN SYSTEM PLUNGES INTO THE PLAINS 
WEDNESDAY WHICH REINFORCES COLD AIR IN THE PLAINS AND BUILDS BROAD 
TROUGH IN THE PLAINS/GREAT LAKES FOR THE LATTER HALF OF THE WEEK. 
BETWEEN THESE TWO NORTHERN SYSTEMS...WE MAY SQUEAK OUT ONE FAIRLY 
NICE DAY ON TUESDAY.

TEMPERATURES SHOULD AVERAGE AT OR BELOW NORMAL THROUGH THE LONG 
TERM...ESPECIALLY SUNDAY AND WEDNESDAY ON BACK SIDE OF NORTHERN 
SYSTEMS...WITH TUESDAY AT OR ABOVE NORMAL. PRECIPITATION CHANCES ARE 
MINIMAL AS DRY AIRMASS REMAINS OR GETS REINFORCED WITH EACH WAVE. 
HAVE REMOVED SMALL POPS FROM OUR SOUTHERN CWA MONDAY INTO TUESDAY AS 
CAUSAL SOUTHERN STREAM WAVE/LOW IS PROGGED WELL SOUTH OF THE AREA.

AVIATION...
TAF SITES KOFK/KOMA/KLNK 

25/18Z TAFS

VFR CONDITIONS TO PREVAIL THRU THE FCST PD. AS FOR WINDS....SFC 
GUSTS HAVE GENERALLY BEEN AROUND 30KT ALL SITES THIS AFTN.  SFC PRES 
GRADIENT SHOULD BE RELAXING TWD 26/00Z ALLOWING SPEEDS TO DROP TO 
AROUND 10KT OR LESS THEREAFTER. SOME INDICATION THOUGH THAT AS SFC 
WINDS DECOUPLE...LLWS MAY ENSUE TWD 26/06Z. HOWEVER...HAVE OPTED NOT 
TO INCLUDE IN LATEST TAFS DUE TO UNCERTAINTY IF CRITERIA WILL 
ACTUALLY BE MET AND WILL BE RE-EVALUATED BEFORE NEXT TAF ISSUANCE.   

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

$$
PREV FORECAST...
SHORT TERM...MILLER
LONG TERM...DERGAN
AVIATION...DEE