FXUS63 KGID 272039
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
239 PM CST FRI NOV 27 2009

.SHORT TERM...TONIGHT THROUGH 12Z SUNDAY.

VERY QUIET PATTERN SEEN DOMINATING MUCH OF THE REGION THIS AFTERNOON 
AS A FLAT BUT BROAD RIDGE IS IN PLACE ACROSS THE CENTRAL CONUS WHILE 
A STRONG SHORT WAVE WITH AN EMBEDDED CLOSED CIRCULATION IS SEEN ON 
BOTH THE EAST AND WEST COAST.  THIS IS LEAVING THE AREA UNDER A WARM 
AND HIGHLY SUBSIDENT FLOW PATTERN AS ONLY SOME THIN HIGH CLOUD COVER 
IS SEEN STREAMING ACROSS THE REGION.  QUICK EXAMINATION OF REGIONAL 
SURFACE OBSERVATIONS DISPLAYS A FRAGMENTED TROUGH STRUCTURE OVER THE 
REGION WITH ONE TROUGH POSITIONED FROM NORTHEAST NEBRASKA INTO THE 
OKLAHOMA PANHANDLE WHILE FURTHER WEST THE LEE TROUGH IS SEEN NEAR 
THE FRONT RANGE REGION OF COLORADO AND WYOMING.  

AS THE REGION HEADS INTO TONIGHT THROUGH SATURDAY...THE WESTERN 
CONUS TROUGH WILL BREAK INTO A STRONG CLOSED CIRCULATION OVER THE 
DESERT SOUTHWEST AND AN OPEN PORTION OF THE WAVE PROPAGATING QUICKLY 
ALONG THE CANADIAN BORDER.  THE NORTHERN PORTION OF THIS WAVE WILL 
AID IN PUSHING A COLD FRONT CURRENTLY ACROSS MONTANA AND NORTH 
DAKOTA...SOUTHWARD THROUGH THE FORECAST AREA BY EARLY TO MID
AFTERNOON. INITIALLY FOR TONIGHT...MOST OF THE NIGHT WILL STAY ON
THE WARMER SIDE AHEAD OF THE FRONT WITH SOUTHWEST WINDS AIDING IN
TEMPERATURES STAYING IN THE MID 20S TO MID 30S OR AROUND 5 TO 10
DEGREES ABOVE SEASONAL NORMALS FOR LOWS. HOWEVER...ON THE FLIP
SIDE OF THE FRONT FOR SATURDAY AFTERNOON...HIGH TEMPERATURES WILL
BE TRICKY GIVEN THE FRONTAL PASSAGE OCCURRING MAINLY DURING THE
MORNING HOURS BUT WILL AIM FOR HIGHS IN THE MID TO UPPER 50S.

SATURDAY NIGHT WILL THEN TURN SLIGHTLY MORE ACTIVE AS THE UPPER 
TROUGH AXIS SWINGS EAST INTO THE REGION.  A WEAK COUPLED JET 
STRUCTURE AHEAD OF THE TROUGH AXIS WILL PRODUCE SOME MODEST 
LIFT/FRONTOGENESIS IN THE 700-600MB LAYER STARTING LATE SATURDAY
NIGHT. DESPITE LIMITED MOISTURE IN THE LOWER 5-10KFT OF THE
ATMOSPHERE AND THE FACT THE FRONTOGENETIC FORCING MOVES SWIFTLY
SOUTH...EXPECT THIS WILL PRODUCE ENOUGH DENDRITIC LAYER SEEDING TO
BRING SOME SNOW FLURRIES NORTH OF A BEAVER CITY TO COLUMBUS
LINE...MAINLY AFTER 3 TO 4 AM.

.LONG TERM...SUNDAY THROUGH FRIDAY. FOCUS IS ON ALTERNATING PERIODS
OF CAA/WAA THROUGH THE EXTENDED WITH THE MAIN QUESTION ON HOW COLD
WILL IT BE AT THE END OF NEXT WEEK? COLD AIR WILL CONTINUE TO
ADVECT SOUTHEAST ACROSS OUR CWA SUNDAY MORNING AS A LOBE OF
SHORTWAVE ENERGY TRANSLATES SOUTHEASTWARD FROM THE DAKOTAS INTO
IOWA. FRONTOGENETIC FORCING...LIFT/MOISTURE IN THE DENDRITIC LAYER
AND ENHANCED JET DYNAMICS MAY LEAD TO SOME FLURRIES/SPRINKLES
EARLY SUNDAY MORNING AS THE SYSTEM MOVES THROUGH. FORECAST
SOUNDINGS SHOW THE LOWLEVEL TEMP PROFILE IS WARM/ABOVE FREEZING IN
OUR SOUTH AND WENT WITH A FLURRY/SPRINKLE MENTION THERE. OVERALL
PCPN CHCS ARE NOT OVERLY SIGNIFICANT/JUST A TRACE EVENT BUT CANNOT
RULE OUT THE POSSIBILITY EITHER. THE COLD AIR WHICH ARRIVES IN THE
MORNING ON SUNDAY GRADUALLY SHIFTS EASTWARD SUNDAY AFTN/NIGHT AND
HEIGHTS RISE BEHIND THE DEPARTING SYSTEM. TEMPS ARE TRENDING A
COUPLE OF DEGREES WARMER SUNDAY AND WENT WITH THIS TREND WITH
HIGHS MAINLY IN THE LOWER 40S.

MONDAY AND TUESDAY WILL SEE A WARMING CONDITIONS WITH DRY AND MILD 
WEATHER IN BETWEEN A CUTOFF LOW PRESSURE SYSTEM ACROSS MEXICO AND 
ADVANCING/TROUGH CLIPPER TRANSLATING SOUTHEASTWARD FROM THE WESTERN 
CANADIAN PROVINCES.  AFTER THE COOLER DAY ON SUNDAY TEMPERATURES ARE 
EXPECTED TO RETURN TO THE 50S FOR HIGHS MON/TUES.  

A COLD FRONT ASSOCIATED WITH THE NORTHERN CLIPPER SYSTEM WILL CROSS 
OUR CWA TUESDAY AFTN/EVENING AND COLD AIR FUNNELS SOUTH TUESDAY 
NIGHT/WEDNESDAY.  H85 TEMPS PLUMMET TO -5 TO -7C DEPENDING ON THE 
MODEL AND RESULTANT DAYTIME TEMPS SHOULD PRIMARILY BE IN THE 30S.  
MODELS DIFFER BY DAYS 6/7 AND THE EVOLUTION/PLACEMENT OF THE POLAR 
VORTEX AND SUBSEQUENTLY ON THE PUSH OF ARCTIC AIR ACROSS THE 
PLAINS.  THE OPERATIONAL GFS HAS BEEN AN OUTLIER AMONG THE EXTENDED 
MODELS WITH THE LOW IN THE HUDSON BAY AND THE WESTERN RIDGE OVER THE 
ROCKIES.  THE 12Z ECMWF HAS TRENDED EASTWARD WITH THE SYSTEM BUT 
STILL IS POSITIONED FARTHER WEST THAN THE GFS OVER ONTARIO THROUGH 
THE GREAT LAKES REGION/UPPER MIDWEST WITH THE WESTERN RIDGE STILL IN 
THE PACIFIC.  ALTHOUGH STILL NOT A CLEAR PICTURE FOR DAYS 6/7 
GENERAL CONSENSUS AMONG MODELS AND HPC IS THAT ARCTIC AIR SHOULD 
SETTLE INTO THE PLAINS BY THE END OF NEXT WEEK.  H85 TEMPERATURES 
ARE PROGGED IN THE -10 TO -12 RANGE AND IF THAT VERIFIES TEMPS WILL 
STRUGGLE IN THE 20S.  FOR NOW HAVE KEPT READINGS IN THE 30S IN CASE 
MODELS CONTINUE TO TREND FARTHER NORTH/EAST WITH THE MAIN VORTEX.  
HAVE KEPT CONDITIONS DRY FOR NOW NEXT WEEK BUT WOULD NOT BE 
SURPRISED TO SEE FLURRIES OR LIGHT SNOW WITH THE COLD PUSH...BUT 
CHCS DO NOT APPEAR GREAT ENOUGH TO WARRANT MENTION JUST YET.

&&

.AVIATION...FOR THE 18Z KGRI TAF. VERY QUIET WEATHER PERIOD
EXPECTED FOR THE GRAND ISLAND TERMINAL AS ONLY SOME THIN MID TO
HIGH CLOUD COVER WILL STREAM ACROSS THE AREA. A WEAK COLD FRONT
WILL PUSH THROUGH THE AREA LATER TONIGHT WITH LIGHT WINDS TURNING
TO THE NORTHWEST AT AROUND 7 TO 10 KNOTS BY SUNRISE.
HOWEVER...LITTLE ELSE WILL RESULT FROM THIS FRONTAL PASSAGE AS THE
VISIBILITY REMAINS UNLIMITED.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$