FXUS63 KOAX 010234
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
834 PM CST FRI DEC 31 2010
.UPDATE...
UPDATED FORECAST TO ADJUST CLOUD FORECAST TONIGHT AND TO EXTEND
WIND CHILL ADVISORY A LITTLE IN TIMING/AREAL EXTENT.
&&
.DISCUSSION...
CLOUDS HAVE BASICALLY CLEARED OUT OF SOUTHEAST/EAST CNTRL NEBR/SW
IA BUT WERE SPREADING ACROSS NERN NEBR. ADJUSTED SKY GRIDS TO
REFLECT THIS TREND. OTHER CLOUDS WERE SPREADING EWD ACROSS SCNTRL
NEBR...BUT IT IS NOT ENTIRELY CLEAR HOW MUCH OF THESE WILL HOLD
TOGETHER SOUTH OF THE PLATTE RIVER. BASED ON CURRENT TRENDS EXTENDED
WIND CHILL ADVISORY A FEW COUNTIES SOUTH AND EAST...ALTHOUGH SWRN
END COULD ACTUALLY SEE SOME IMPROVEMENT LATER IF CLOUDS CONTINUE
SPREADING EWD. IN FACT...IF CLOUDS DON/T MAKE IT TOWARD MO RIVER
NEAR OMA LATER TNGT...COULD ACTUALLY SEE COUNTIES FARTHER SE
REACHING CRITERIA WHILE THOSE WNW NOT AS COLD. BOTTOM LINE...IN
ANY EVENT A COLD AND BLUSTERY NEW YEARS EVE. ALSO ADJUSTED A FEW
LOWS DOWN BASED ON CURRENT TRENDS...BUT CLOUDS HAVE HALTED/REVERSED
FALL NEAR/NW OF OLU. CHERMOK
&&
.PREV DISCUSSION... /ISSUED 304 PM CST FRI DEC 31 2010/
SHORT TERM...TONIGHT THRU MONDAY.
WITH LARGE UPPER SYSTEM NOW EXITING THE AREA...MUCH QUIETER
WEATHER IS EXPECTED OVER THE NEXT FEW DAYS. COLD TEMPS/WIND
CHILLS AND A FEW LEFT OVER FLURRIES IN OUR FAR NW WILL BE THE ONLY
WEATHER IN THE NEAR TERM.
MID/UPPER LOW IS CURRENTLY CENTERED NEAR CNTRL NEBRASKA WITH DRY
AIR PUNCH MOVING NWD ACROSS ENTIRE CWA. RADAR MOSAIC RETURNS SHOW
ALL ACTIVITY HAS PUSHED WELL TO OUR NORTH AND NORTHWEST AS LARGE
SCALE FORCING IN ASSOCIATION WITH MID/UPPER LOW MOVES NEWD WITH
TIME. AS MENTIONED ABOVE...MAIN FORECAST CONCERNS WILL BE TEMPS
AND WIND CHILLS WITH SFC LOW NOW OVER NCNTRL IA AND A TIGHTENING SFC
GRADIENT AS HIGH PRESSURE BUILDS IN FROM THE WEST. SFC TEMPS
SHOULD DROP INTO THE SINGLE DIGITS ABOVE ZERO IN OUR SOUTH TO THE
SINGLE DIGITS BELOW ZERO IN THE NORTH. WITH SFC WINDS OVERNIGHT
AND INTO EARLY SAT MORNING OF NEARLY 20 KTS IN THE NORTHWEST
COUNTIES...WIND CHILLS WILL DROP INTO ADVISORY CATEGORY FOR A
WHILE. WL CONTINUE WITH A WIND CHILL ADVISORY THRU 12Z SAT FOR OUR
NW COUNTIES.
SLUG OF ARCTIC AIR WILL MOVE NEWD ALONG WITH THE DEPARTING STORM SYSTEM
WHILE AN AREA OF SFC HIGH PRESSURE BUILDS OVER THE SRN PLAINS.
TEMPERATURES WILL REMAIN COLD THRU SUNDAY AS SECONDARY MID/UPPER
WAVE PUSHES THRU THE AREA BUT ONCE THIS PASSES BY SUNDAY
NIGHT...SOME WAA IS EXPECTED ACROSS OUR SRN COUNTIES. ANOTHER
UPPER TROF WL PUSH ACROSS THE NRN PLAINS LATE MONDAY INTO TUESDAY
WHICH WILL BRING ANOTHER PUSH OF COLD TEMPS INTO OUR NRN COUNTIES.
NO PCPN IS EXPECTED HOWEVER WITH THE MAIN DYNAMICS REMAINING FAR
TO OUR NORTH.
LONG TERM...MONDAY NIGHT THROUGH FRIDAY.
A SHORTWAVE TROF WILL SWING THRU THE UPPER MISSISSIPPI VALLEY MONDAY
NIGHT. SOME FLURRIES MAY EXTEND SOUTHWARD INTO NORTHEAST NEBRASKA
WITH SOME COOLER TEMPERATURES EARLY TUESDAY MORNING. A MID
TROPOSPHERIC TROF REMAINS OVER THE REGION WEDNESDAY WITH ANOTHER
WEAK SFC TROF PASSAGE. THE 12Z ECMWF HAD A STRONGER MID LEVEL LOW
OVER THE FCST AREA WITH PRECIP WED. THIS IS A NEW FEATURE WITH THIS
RUN SO WILL NOT CHANGE ADD PRECIP FOR THIS UNTIL THERE IS BETTER
CONSISTENCY. TEMPERATURES WILL REMAIN SEASONABLE WITH HIGHS IN THE
20S AND 30S. THERE ARE SOME DIFFERENCES THURSDAY INTO FRIDAY AS TO
WHETHER THERE WILL BE ANOTHER MID LEVEL TROF PASSING THROUGH THE
REGION OR SOME MID LEVEL RIDGING. THE GFS/NAEFS SHOW MEMBERS OF
EACH WITH COOLER TEMPERATURES MORE PREVALENT...WHILE THE ECMWF AND
ECMWF ENSEMBLES ARE MORE MILD. THE 12Z ECMWF IS MILD FOR
THURSDAY...WITH COOLING FM THE NORTH FRIDAY. AT THIS TIME TRENDED
WITH THE COOLER TEMPERATURES WITH IN THE 20S AND 30S. STILL MAINLY
DRY IN THE EXTENDED...BUT COULD GET CLIPPED BY THE SYSTEM EARLY
TUESDAY MORNING. THERE COULD BE A THERMAL BOUNDARY BETWEEN THE MORE
MILD PACIFIC FLOW AND THE ARCTIC COOLING THAT SPREADS SOUTH WITH
HIGHER RH.
AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
SIGNIFICANT PCPN ENDED AT TAF SITES EARLIER. MVFR CONDITIONS OVER THE
AREA AT EARLY AND MID AFTERNOON SHOULD IMPROVE TO VFR OVERNIGHT AS
SURFACE LOW TRACKS ACROSS MINNESOTA TONIGHT...WITH WEST OR NORTHWEST
WINDS AT ALL THREE SITES. MODELS SHOW SOME MOISTURE MOVING IN BETWEEN
925 MB AND 850 MB SATURDAY MORNING...SO AREAS OF MVFR COULD MOVE
BACK IN AFTER 12Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WIND CHILL ADVISORY UNTIL 9 AM CST SATURDAY FOR NEZ011-012-
015>018-030>034-042-043-050-065.
IA...WIND CHILL ADVISORY UNTIL 9 AM CST SATURDAY FOR IAZ043.
&&
$$
KERN/ZAPOTOCNY/MILLER