FXUS63 KLBF 252042
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
240 PM CST WED NOV 25 2009
.SYNOPSIS...
IN THE UPPER LEVELS...6.7 MICRON IMAGERY SHOWED A DEVELOPING
WAVE OFF THE WASHINGTON-BRITISH COLUMBIA COAST AND A CLOSED
CIRCULATION OVER THE CENTRAL CALIFORNIA COAST. OTHERWISE...THE RIDGE
OVER THE WESTERN INTER-MOUNTAIN REGION WAS MAKING ITS WAY EASTWARD.
HAND ANALYSIS OF THE 20Z SURFACE DATA SHOWS HIGH PRESSURE OVER THE
WESTERN INTER-MOUNTAIN REGION. A WARM FRONT STRETCHED FROM AN
INTENSE CLOSED LOW IN THE GULF OF ALASKA ACROSS NORTHERN BRITISH
COLUMBIA AND THROUGH CENTRAL ALBERTA INTO EASTERN MONTANA.
ANOTHER...EVEN STRONGER...SURFACE LOW COULD BE SEEN IN THE BERING
SEA.
&&
.SHORT/MEDIUM RANGE...TONIGHT THROUGH SATURDAY NIGHT.
AS THE UPPER LOW MOVES OUT OF THE PLAINS AND ACROSS THE
MISSISSIPPI VALLEY TONIGHT AND THURSDAY...AN UPPER RIDGE WILL COME
IN FROM THE WEST AND BRING WARMER TEMPERATURES TO CENTRAL AND
WESTERN NEBRASKA. IN FACT...UNSEASONABLY WARM TEMPERATURES ARE
LIKELY THURSDAY AND AGAIN FRIDAY.
A FRONT IS EXPECTED TO COME THROUGH WESTERN NEBRASKA FRIDAY
NIGHT AND SATURDAY AND COLDER TEMPERATURES ARE AGAIN EXPECTED. THE
HIGHS SATURDAY WILL STILL BE ABOVE NORMAL...BUT THEY MAY BE REACHED
FAIRLY EARLY IN THE DAY AND WILL NOT BE NEARLY AS WARM AS FRIDAY OR
EVEN THURSDAY. COLD ADVECTION MAY BE STRONG ENOUGH FOR A NON-DIURNAL
TEMPERATURE TREND SATURDAY...BUT THERE IS SOME UNCERTAINTY REGARDING
THE STRENGTH AND TIMING OF THE COLD ADVECTION. ALSO...THE FRONT IS
FAST MOVING AND FAIRLY STRONG...SO A MENTION OF SNOW SHOWERS IS
APPROPRIATE SATURDAY NIGHT.
.LONG RANGE...SUNDAY THROUGH WEDNESDAY.
BIG NEWS WILL COME TOWARD THE END OF THE PERIOD...WHEN ALL
MODELS ARE INDICATING A SIGNIFICANT INTRUSION OF ARCTIC AIR INTO THE
CENTRAL AND NORTHERN PLAINS. BEFORE HAND...SUNDAY THOUGH
TUESDAY...WEATHER SHOULD BE RATHER BENIGN. A COLD FRONT DOES PLOW
THROUGH THE AREA ON SATURDAY...WITH BREEZY AND CHILLY CONDITIONS
BEHIND THE FRONT ON SUNDAY. THE LATEST RUNS OF BOTH THE GFS AND
ECMWF INDICATE RIDGING MONDAY AND TUESDAY AHEAD OF THE ARCTIC BLAST
ANTICIPATED FOR WEDNESDAY. SHOULD SEE HIGHS IN THE 40S TO AROUND 50
BOTH MONDAY AND TUESDAY...WITH 30S FOR WEDNESDAY BEHIND THE FRONT.
CURRENT INDICATIONS ARE THAT ENOUGH FORCING WILL BE PRESENT WITH THE
FRONTAL BOUNDARY WEDNESDAY TO INCLUDE A SLIGHT CHANCE OF SNOW
SHOWERS. BEYOND WEDNESDAY THE REST OF THE WEEK IS LOOKING DOWNRIGHT
COLD...ESPECIALLY IF ECMWF IS CORRECT IN DROPPING THE ENTIRE ARCTIC
AIRMASS INTO THE CONUS.
&&
.AVIATION...
WINDS SHOULD DIMINISH RAPIDLY LATE THIS AFTERNOON ACROSS WESTERN
AND CENTRAL NEBRASKA...WITH LIGHT WEST WINDS UNDER 10 KTS FOR THE
OVERNIGHT HOURS AND INTO THURSDAY MORNING. SKIES SHOULD BE CLEAR
AFTER ANY STRATOCUMULUS DIMINISHES LATE THIS AFTERNOON.
&&
.LBF
WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT/MEDIUM RANGE...SPRINGER
AVIATION/EXTENDED...TAYLOR