FXUS63 KOAX 102004
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
204 PM CST THU DEC 10 2009

.SHORT TERM...TONIGHT THROUGH SUNDAY.

TEMPERATURES THE NEXT FEW DAYS...AND INCREASING MOISTURE/PRECIP 
CHANCES SATURDAY INTO SUNDAY...ARE THE PRIMARY FORECAST CONCERNS.

TEMPERATURES HAVE REBOUNDED INTO THE TEENS THIS AFTERNOON AFTER 
MORNING LOWS IN THE 4 BELOW TO 15 BELOW RANGE. DESPITE DEEP SNOW 
COVER ACROSS THE CWA...SOUTHWEST WINDS GUSTING TO 20KTS WERE 
RESPONSIBLE FOR THE WARMING TREND OWING TO RELATIVELY TIGHT PRESSURE 
GRADIENT BETWEEN HIGH PRESSURE IN OKLAHOMA AND A WEAK LOW MOVING 
THROUGH THE NORTHERN HIGH PLAINS. GRADIENT WEAKENS TONIGHT AS 
SURFACE HIGH SHIFTS THROUGH THE LOWER MISSISSIPPI VALLEY. WEAK LOW 
WILL DIVE SOUTHEAST INTO NORTHERN IOWA BY LATE TONIGHT...WITH MAIN 
IMPACT BEING SCATTERED CLOUDS OVER THE NORTHERN CWA. ALL THIS YIELDS 
ANOTHER TRICKY TEMPERATURE FORECAST OVERNIGHT. WINDS WILL LIKELY 
DIMINISH TO LESS THAN 5KTS IN MOST AREAS...ESPECIALLY GIVEN LOW 
LEVEL INVERSION OVER SNOW FIELD. BUT TENDENCY FOR SOME WIND AS LOW 
APPROACHES WITH INCREASING CLOUDS WILL LIMIT TEMPERATURE FALL. HAVE 
LOWS RANGING FROM THE 5 TO 10 BELOW IN THE SOUTHEAST CWA WHERE 
WINDS/CLOUDS WILL AFFECT TEMPS THE LEAST...TO NEAR ZERO IN THE NORTH 
WHERE BETTER FLOW/CLOUDS WILL KEEP TEMPS UP SOME. HOWEVER WILL HAVE 
A BIG BUST POTENTIAL IF CLOUDS DO NOT MATERIALIZE AND WINDS GO CALM 
FOR AN EXTENDED PERIOD. WILL ALSO HOLD OFF ON ANY WIND CHILL 
ADVISORIES AS WIND CHILLS ONLY APPROACH 20 BELOW IN THE COLDEST 
SPOTS. AND IF WINDS STAY UP...TEMPS SHOULD REMAIN ELEVATED ENOUGH TO 
PUT WIND CHILLS DOWN IN THE 15 BELOW RANGE.

FRIDAY IS AGAIN TRICKY WITH WINDS REMAINING LIGHT MOST OF THE DAY. 
SOME RETURN SOUTHERLY FLOW WILL KICK IN DURING THE AFTERNOON...BUT 
LIKELY NOT SOON ENOUGH TO REALLY WARM TEMPS. THUS HAVE HIGHS A GOOD 
8 DEGREES OR SO BELOW SIMILAR MAV/MET GUIDANCE WITH TEENS IN THE 
EAST AND LOWER 20S WEST.

APPROACHING MID LEVEL WAVE SHOULD HELP TIGHTEN PRESSURE GRADIENT 
FRIDAY NIGHT INTO SATURDAY. RETURNING LOW LEVEL MOISTURE AND 
ISENTROPIC UPGLIDE ON THE 295/300K PRESSURE SURFACES SUGGESTS 
INCREASING CLOUDS WILL RULE AS WELL. BOTH FACTORS POINT TO WARMER 
TEMPERATURES FRIDAY NIGHT AND SATURDAY...WITH LOWS IN THE SINGLE 
DIGITS AND TEENS...AND HIGHS SATURDAY IN THE 20S. MID LEVEL WAVE IS 
A DAY EARLIER THAN MODEL RUNS SUGGESTED YESTERDAY...SO HAVE ADJUSTED 
FORECAST ACCORDINGLY. FORECAST SOUNDINGS SHOW EVEN MORE/DEEPER 
MOISTURE THAN PREVIOUS RUNS...WITH AFOREMENTIONED UPGLIDE PROVIDING 
WEAK LIFT OVER OUR EASTERN CWA. WITH DRY MID LEVELS...TOP DOWN 
PRECIP SCHEMES POINT TO DRIZZLE AS MAIN WEATHER TYPE. HAVE NOT 
BOUGHT INTO SIGNIFICANT WARMING SUGGESTED BY MOS GUIDANCE...AND WILL 
KEEP TEMPERATURES BELOW FREEZING THROUGH SATURDAY NIGHT. THUS HAVE 
INSERTED A CHANCE FOR FREEZING DRIZZLE SATURDAY AFTERNOON AND 
EVENING BEFORE MOISTURE/WAVE LIFT NORTHEAST OF OUR AREA.

SUNDAY SHOULD NOW BE DRY AS NEXT WAVE SETS UP FOR MONDAY. HAVE 
REMOVED MENTION OF PRECIP THEN. MODELS ARE IN AGREEMENT IN KEEPING 
SOUTHERLY FLOW ACROSS THE CWA THROUGH THE AFTERNOON...SO BUMPED 
TEMPERATURES INTO THE MID 20S TO LOWER 30S RANGE.

DERGAN

.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY.  

HAVE MAINTAINED GENERAL FORECAST TRENDS IN THE EXTENDED PERIOD WITH
TEMPERATURES THE MAIN CONCERN AS ANOTHER ROUND OF ARCTIC AIR 
INDICATED BY THE 12Z GFS EARLY NEXT WEEK. 00Z ECMWF NOT AS SHARP 
WITH ITS UPPER PATTERN DURING THIS TIME AND THUS KEEPS COLDER AIR 
FURTHER NORTH. HPC IDEA TODAY WAS TO GO WITH A BLEND OF SOLUTIONS
AND BRING DOWN SOME COLD AIR BUT NOT AS COLD AS GFS WOULD INDICATE. 

BEYOND THIS TIME ECMWF AND GFS REMAIN OUT OF PHASE WITH THE UPPER 
FLOW SO FOLLOWED TODAYS HPC GUIDANCE AT THIS TIME.

FOBERT

&&

.AVIATION...
TAF SITES KOFK/KOMA/KLNK 

18Z TAFS

VFR CONDITIONS ARE EXPECTED WITH CLEAR SKIES AND SOUTHWEST WINDS.

KERN

&&

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

$$