FXUS63 KGID 280532
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1132 PM CST FRI NOV 27 2009
.AVIATION...06Z TAF. QUIET TAF PERIOD EXPECTED WITH VFR
CONDITIONS. PRIMARY CONCERN WILL LIE WITH WINDS...AS A COLD FRONT
PUSHES THROUGH THE REGION. TIMING OF THIS FRONT BRINGS IT THROUGH
THE GRI TERMINAL NEAR SUNRISE...WITH NNW WINDS BUILDING IN BEHIND.
THESE WINDS WILL CONTINUE THROUGH THE END OF THE TAF PERIOD...AND
WILL INCREASE IN SPEED FOR THE AFTERNOON/EVENING HOURS. CLOUD
COVER IS ALSO EXPECTED TO INCREASE THROUGH THE DAY...BUT WONT
CAUSE ANY RESTRICTIONS.
&&
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.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
