FXUS63 KOAX 120901
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
301 AM CST SAT DEC 12 2009

.DISCUSSION...

MAIN FORECAST CHALLENGES REVOLVE AROUND CHANCE OF LIGHT FREEZING
DRIZZLE LATER TODAY THROUGH THE EVENING...THEN CHANCE FOR
ADDITIONAL WINTRY MIXTURE OF PRECIPITATION SUNDAY NIGHT THROUGH
MONDAY. 

LOW LEVEL MOISTURE WAS MOVING NORTHWARD INTO PORTIONS OF SOUTHEAST
NEBRASKA AND SOUTHWEST IOWA EARLY THIS MORNING...AND THIS TREND
WILL CONTINUE THROUGH THE DAY. NO SIGNS OF ANY DRIZZLE JUST...BUT
AS A WEAK UPPER LEVEL IMPULSE NOW DEPICTED MOVING THROUGH CENTRAL
COLORADO ON RECENT WATER VAPOR IMAGERY MOVES ONTO THE PLAINS THIS
AFTERNOON...COULD SEE SOME SPOTTY DRIZZLE DEVELOP IS CONDENSATION
PRESSURE DEFICITS ON THE 280 SURFACE ARE VERY LOW. ONLY QUESTION...
WILL THERE BE ENOUGH UPPER VERTICAL MOTION AND MOISTURE DEPTH TO
GENERATE ANY MEASURABLE PRECIPITATION. GFS/NAM/ECMWF/GEM ALL
SUGGEST AT LEAST A HUNDREDTH OR TWO OF AN INCH MAY BE POSSIBLE
SOUTH AND EAST OF A LINE FROM ABOUT LINCOLN TO OMAHA. THE SREF
REMAINS DRY...AS DOES HPC. BELIEVE THE MOISTURE IS JUST TOO
SHALLOW REMAINING BELOW 850 MB...AND THUS WILL STICK WITH DRIZZLE
FOR NOW...ALTHOUGH A FEW HOURS OF DRIZZLE COULD CERTAINLY TICK OFF
ONE OR TWO HUNDREDTHS OF AN INCH. SURFACE TEMPERATURES WILL BE ON
THE RISE TOO TODAY...BUT FEEL THAT MOS ABSOLUTE MAX TEMPS ARE TOO
HIGH...AND HAVE FORECAST HIGHS MORE IN LINE WITH 3 HOURLY GUIDANCE
VALUES...WHICH WOULD KEEP THE ENTIRE AREA BELOW FREEZING. THE ONLY
PLACE THAT COULD MAKE A RUN FOR FREEZING OR ABOVE MIGHT BE NEAR
THE NE/KS BORDER REGION...BUT ONLY HAVE TEMPS AT 32 THERE FOR NOW.
THUS...ANY DRIZZLE THAT DEVELOPS WILL OCCUR WITH SURFACE TEMPERATURES
BELOW FREEZING. HAVE NOT OPTED FOR ANY TYPE OF HEADLINE ATTM...AS
NOTHING HAS MATERIALIZED YET...BUT IT DOESN'T TAKE MUCH FREEZING
DRIZZLE TO CAUSE A SERIOUS PROBLEM. WILL CONTINUE TO HIGHLIGHT IN
OUR HAZARDOUS WEATHER OUTLOOK FOR NOW THOUGH. IF THE DRIZZLE DOES
DEVELOP...IT LIKELY WOULD LINGER INTO THE EVENING ACROSS THE MISSOURI
RIVER VALLEY REGION...BUT HAVE PULLED AFTER MIDNIGHT AS UPPER IMPULSE
MOVES EAST OF THE AREA.

AFTER A BRIEF BREAK ON SUNDAY...THE NEXT WAVE OF INTEREST...WHICH
IS CURRENTLY DEPICTED AS A SPLIT FLOW ACROSS THE PACIFIC AND
SOUTHWESTERN CANADA...MOVES INTO THE NORTHWESTERN CONUS AND
INDUCES CYCLOGENESIS ACROSS THE CENTRAL ROCKIES. MODELS HINT AT
SOME LIGHT QPF ACROSS NORTHEAST NEBRASKA SUNDAY AFTERNOON WITHIN
THE WARM AIR ADVECTION PATTERN...BUT WILL HOLD OFF UNTIL SUNDAY
NIGHT WHEN BETTER QUALITY MOISTURE MOVES INTO THE AREA. THERMAL
PATTERNS AND BUFKIT PROFILES INDICATE ALL SNOW ACROSS NORTHEAST
NEBRASKA...FREEZING RAIN ACROSS SOUTHEAST NEBRASKA AND SOUTHWEST
IOWA...AND PERHAPS A WINTRY SLEETY MIXTURE IN BETWEEN. ALTHOUGH...
THE SREF KEEPS PRECIP WELL TO THE NORTH...WITH THE 00Z NAM SUGGESTING
MORE OF A DRIZZLY PATTERN...BUT THE 06Z NAM IS NOW A LITTLE MORE
AGGRESSIVE. BELIEVE A BLEND OF THE GFS/ECMWF HERE SEEMS APPROPRIATE...
WHICH KEEPS THE BULK OF THE HEAVIEST PRECIP TO OUR NORTH...WITH
JUST A LIGHT DUSTING ACROSS PORTIONS OF NORTHEAST NEBRASKA WHERE
I'VE INCREASED POPS INTO THE CHC CATEGORY. SOME LIGHT SNOW COULD
LINGER IN THE MISSOURI VALLEY REGION MONDAY MORNING AS THIS
WEATHER SYSTEM MOVES THROUGH...THEN DRY THEREAFTER.

MORE IMPORTANTLY...TEMPERATURES WILL BE TAKING A PLUNGE AGAIN
FIRST HALF OF THE WEEK AS COLD CANADIAN HIGH PRESSURE MOVES BACK
IN. TRENDED TEMPERATURES DOWN EARLY IN THE WEEK...BUT MAY NOT HAVE
GONE DOWN ENOUGH. BUT...THE GOOD NEWS IS THAT THE COLD AIR WON'T
LAST THAT LONG AS TEMPERATURES BEGIN TO RECOVER FOR THE LATTER
HALF OF THE WEEK.

DEWALD

&&

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

06Z TAFS

THERE IS LITTLE RESISTANCE TO THE MOIST SOUTHWEST FLOW ALOFT AND LOW 
CLOUDS SPREADING ACROSS KANSAS/MISSOURI INTO NEBRASKA/IOWA.  VFR 
CIGS ARE COMMON WITH SOME PATCHY MVFR CIGS ON THE EDGES. KFNB JUST 
CAME IN AT 3100FT. VFR CIGS ARE EXPECTED AT KLNK AND KOMA THIS 
MORNING WITH KOFK ON THE NW EDGE OF THE CIGS...BUT THEY SHOULD GO 
DOWN TOO THIS AFTERNOON.  MEANWHILE...A WEATHER DISTURBANCE IN THE 
ZONAL FLOW ALOFT WILL PASS THROUGH LATE THIS AFTERNOON AND 
TONIGHT...DRAGGING A COOL FRONT THROUGH AFTER 00Z. MVFR CIGS AND 
VSBYS ARE EXPECTED THIS AFTERNOON AND TONIGHT.  FREEZING DRIZZLE IS 
POSSIBLE DURING THE PD WITH THE MVFR CIGS AND AHEAD OF THE 
WINDSHIFT.  TEMPERATURES TRICKY AS A COUPLE OF DEGREES WARMER WOULD 
BE DRIZZLE.  WILL LOOK AT PUTTING IN A COUPLE OF HOURS OF FREEZING 
DRIZZLE LATE AFT/EVE...AT KLNK/KOMA OR JUST TO THE EAST OF THERE.  
CURRENTLY DO NOT HAVE CIGS LIFTING BEHIND FNT...HOWEVER...WILL NEED 
TO MONITOR SHOULD THE NW FLOW BE STRONG ENOUGH TO SCOUR OUT THE LOW 
CLDS.

ZAPOTOCNY

&&

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

$$