FXUS63 KGID 252030
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
230 PM CST WED NOV 25 2009
.SHORT TERM...TONIGHT THROUGH 12Z FRIDAY. BIGGEST FORECAST
CHALLENGE WILL BE WIND SPEEDS FOR WEDNESDAY.
WATER VAPOR LOOP SHOWS THE SHORTWAVE TROUGH WITH CLOSED LOW MOVING
INTO THE MISSISSIPPI VALLEY...HELPING TO REINFORCE THE LONGWAVE
TROUGH TO THE EAST. AN UPPER LEVEL POSITIVELY TILTED HIGHLY
AMPLIFIED RIDGE WITH AN AXIS OVER THE WESTERN UNITED STATES IS
TRANSLATING EAST.
THIS RIDGE WILL CONTINUE TO MOVE EAST THROUGH THE SHORT
TERM...ENSURING DRY CONDITIONS. WARM AIR ADVECTION WILL BE WELL
UNDERWAY BY THURSDAY AFTERNOON AND CONTINUE INTO THURSDAY NIGHT.
WIND SPEEDS WILL BE NOWHERE NEAR WHAT THEY WERE TODAY AS MIXING WILL
BE MUCH MORE SHALLOW FOR THURSDAY...PERHAPS UP TO 900 MB AS OPPOSED
TO NEAR 825 MB FOR TODAY...AND WIND SPEEDS ALOFT WILL BE
SIGNIFICANTLY SLOWER.
KEPT LOWS TONIGHT GENERALLY NOT TOO FAR FROM GUIDANCE VALUES AFTER
BUMPING UP TEMPERATURES A TAD FOR TONIGHT. LOWERED HIGH TEMPERATURES
A BIT IN THE EAST FOR HIGHS ON THURSDAY AND BUMPED UP LOW
TEMPERATURES THURSDAY NIGHT BY SEVERAL DEGREES...GOING WELL ABOVE
GUIDANCE VALUES DUE TO SOME ANTICIPATED WARM AIR ADVECTION. ALSO
BUMPED UP DEWPOINTS FOR THURSDAY NIGHT TO NEAR 30 DEGREES.
.LONG TERM...FRIDAY THROUGH WEDNESDAY. THE EXTENDED PERIODS WILL
SEE VARYING TEMPERATURE EXTREMES FROM WARM TO START (FRIDAY) TO
COLD TO END (WEDNESDAY). BEGINNING ON FRIDAY AN UPPER LEVEL RIDGE OF
HIGH PRESSURE WILL BE CENTERED ACROSS THE CENTRAL PLAINS WITH AN
UNSEASONABLY MILD AIRMASS SETTLING IN. H85 TEMPERATURES ARE
PROGGED BETWEEN 14-16C DEPENDING ON THE MODEL. ALTHOUGH MIXING WILL
NOT REACH THIS LEVEL...THE AIRMASS WILL BE DRY AND MILD AND
WARMING WILL BE AIDED BY A DOWNSLOPE WIND COMPONENT. FOR HIGH
TEMPERATURES...READINGS AROUND 60 OR IN THE LOWER 60S SEEM ON
TARGET WITH PLENTY OF SUN.
ENERGY TRANSLATING ACROSS THE NORTHERN PLAINS FRIDAY NIGHT/SATURDAY
DEAMPLIFIES THE RIDGE AND SHOVES IT EASTWARD. TEMPERATURES COOL
BEHIND THE FRONT WITH READINGS DROPPING BACK TO THE LOW/MID 50S FOR
HIGHS. ON SUNDAY THE UPSTREAM TROUGH EXPANDS ONTO THE PLAINS AND
THE FLOW SPLITS WITH THE MAIN ENERGY ORIENTED ACROSS THE NORTHERN
PLAINS AND ALSO FROM SW KANSAS INTO ARIZONA OR POTENTIALLY AS FAR
SOUTH AS BAJA. THE 12Z ECMWF IS ATTEMPTING TO CLOSE OFF ANOTHER
CIRCULATION IN THE TX/OKLAHOMA PANHANDLE AND SUGGESTS SOME LIGHT
RAIN OR SNOW IS POSSIBLE IN OUR SOUTHERN ZONES WHEREAS THE 12Z GFS
AND THE 00Z ECMWF WAS FARTHER SOUTH WITH THIS. FOR NOW HAVE OPTED
TO KEEP THE FORECAST DRY UNTIL MODELS BECOME MORE CLEAR ON THE
TRACK. REGARDLESS OF AN OUTSIDE CHC FOR PCPN...COLDER BUT MORE
SEASONAL AIR SETTLES IN ON SUNDAY WITH THE TROUGH. THE AIRMASS
MODERATES SOMEWHAT MONDAY INTO TUESDAY...BUT NOT NEAR WHERE TEMPS
HAVE BEEN FOR MUCH OF NOVEMBER. MODELS ARE MORE CONSISTENT IN A
STRONG COLD FRONT ARRIVING WITH A DIGGING CANADIAN/NORTHERN PLAINS
TROUGH REACHING OUR REGION ON WEDNESDAY AND THIS REGIME SETTLES IN
INTO NEXT WEEKEND. H85 TEMPS PLUMMET TO NEGATIVE 8C ON WEDNESDAY
AND THE EC IS COLDER THAN THE GFS BY NEXT WEEKEND WITH H85 TEMPS
AROUND DROPPING TO -14C. OVERALL BY THE END OF NOVEMBER COLDER AIR
WILL MAKE A COMEBACK WITH DECEMBER CONDITIONS STARTING OUT MORE
SEASONAL. WITH THE ARRIVAL OF THE FRONT/SYSTEM ON WEDNESDAY DID
INSERT A SMALL POP FOR LIGHT SNOW WHICH MAY MAY END UP MORE LIKE
FLURRIES WITH THE FRONT/CLIPPER.
&&
.AVIATION...18Z KGRI TAF. THE BIG ISSUE WILL BE WIND SPEEDS.
NORTHWEST WIND WILL BE GUSTING TO AROUND 35 KTS THIS AFTERNOON AS
WE MIX UP TO AROUND 825 MB. WIND SHOULD QUICKLY SUBSIDE BY AROUND
00Z NEAR SUNSET...AND WILL BECOME MORE OF A WEST DIRECTION BY
THURSDAY MORNING...BUT WILL REMAIN LIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
