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000
FXUS63 KLBF 302354 AAA
AFDLBF

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
554 PM CST SAT NOV 30 2013

.SYNOPSIS...
ISSUED AT 258 PM CST SAT NOV 30 2013

A DEEP UPPER LEVEL LOW OVER ALASKA WILL MOVE SOUTH ALONG
THE COAST OF BRITISH COLUMBIA AND BE OVER WASHINGTON STATE MONDAY.
UPSTREAM...A VERY STRONG UPPER LEVEL BLOCKING RIDGE WILL DEVELOP
ACROSS ALASKA GENERATING A 1052 MB ARCTIC HIGH WHICH WILL MIGRATE
SOUTH THROUGH WRN CANADA. THIS ARCTIC HIGH WILL LIKELY PRODUCE
SUBZERO HIGHS ACROSS NORTH DAKOTA WITH HIGHS IN THE TEENS AND 20S
ACROSS NEBRASKA WEDNESDAY THROUGH SATURDAY.

THE MAIN PROBLEM WITH THIS FORECAST IS THE TEMPERATURE FORECAST BOTH
AHEAD AND BEHIND THE ARCTIC FRONT. THE SNOW CHANCES ARE LOW TUESDAY
AND WEDNESDAY...AROUND 30 PERCENT WITH LIMITED MOISTURE AND
DYNAMICAL FORCING.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 258 PM CST SAT NOV 30 2013

WEST TO NORTHWEST FLOW ALOFT AND TRANQUIL CONDITIONS IN THE SHORT
TERM. DO LOOK FOR SOME INCREASE IN MID AND HIGH LEVEL CLOUDS DURING
THE NEXT 24 HRS...AND THIS COULD HAVE SOMEWHAT OF AN IMPACT ON HIGH
TEMPERATURES SUNDAY. CLOUDS SHOULD BE MOST THICK ACROSS NORTH
CENTRAL NEBRASKA...AND THIS IS WHERE HIGH TEMPERATURES WILL BE HELD
IN THE 40S. LOWER TO MID 50S EXPECTED AGAIN ACROSS SOUTHWEST
NEBRASKA...WHERE A WESTERLY DOWNSLOPE WIND SHOULD HELP BOOST
TEMPERATURES.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 258 PM CST SAT NOV 30 2013

SUNDAY NIGHT THROUGH TUESDAY...SATELLITE SHOWS AN EXTENSIVE AREA OF
MID AND HIGH LEVEL CLOUDINESS ACROSS THE NORTH PACIFIC. THE NAM80
AND GFS MOVE THESE CLOUDS ACROSS THE FCST AREA MONDAY. THIS CLOUD
SYSTEM COULD AFFECT MAX TEMPERATURES BY AS MUCH AS 10 DEGREES MONDAY
VERSUS A FULL SUN FORECAST. GUIDANCE SHOWS HIGHS IN THE 50S AND 60S
WHICH IS LIKELY A FULL SUN FORECAST. THE OFFICIAL FCST USES 50S TO
NEAR 60 FOR HIGHS WHICH MIGHT BE GENEROUS GIVEN THE AMOUNT OF
EXPECTED CLOUD COVER.

THE 12Z NAM AND GFS SHOW A STRONG LEAD SHORT WAVE WHICH WOULD DRIVE
THE ARCTIC FRONT THROUGH THE FCST AREA TUESDAY MORNING FOR HIGHS IN
THE 20S NORTH BUT NEAR 60 SOUTH. THE 12Z GEM AND 12Z ECM ARE SLOWER AND
BRING THE FRONT THROUGH DURING THE AFTERNOON FOR HIGHS IN THE 40S
AND 50S TO NEAR 60. THE FCST USES A FOUR WAY BLEND OF THESE MODELS
AT THE 18Z TUESDAY FORECAST POINT FOR HIGHS IN THE 30S AND 40S.
STAY TUNED FOR UPDATES ON THIS FORECAST.

SOME LIGHT SNOW IS POSSIBLE TUESDAY BEHIND THE FRONT AS SHOWN BY THE
GFS AND NAM AND THE GEM AND ECM...WHENEVER THE FRONT ARRIVES. THIS
IS MAINLY ACROSS SHERIDAN COUNTY. NO FREEZING RAIN OR SLEET WAS
INDICATED IN THE GFS OR NAM BUT WAS SHOWN IN THE 12Z ECM.

TUESDAY NIGHT THROUGH SATURDAY...
TEMPERATURES WEDNESDAY WILL BE STEADY OR FALLING IN THE TEENS AND
20S WITH THE ARCTIC BLAST IN FULL SWING. H850 TEMPERATURES HOVER AT
-15C TO -20C THURSDAY AND FRIDAY AND THEN WARM A BIT SATURDAY AS
SOUTHERLY RETURN FLOW DEVELOPS. DONT BE FOOLED THOUGH...THE SOUTH
WINDS ARE RECIRCULATING ARCTIC AIR NORTH. HIGH TEMPS IN THE TEENS
ARE EXPECTED THURSDAY AND FRIDAY...20S ON SATURDAY. WIND CHILL
READINGS OF -10F TO -20F ARE POSSIBLE WEDNESDAY NIGHT AND THURSDAY
MORNING. WINDS DECREASE THEREAFTER.

LIGHT SNOW IS POSSIBLE TUESDAY NIGHT THROUGH THURSDAY. MODEL BLEND
QPF IS 0.05 TO 0.15 INCHES SO BETWEEN 1/2 AND 1.5 OF INCHES OF
SNOW IS POSSIBLE. GIVEN THE MODELS ARE TOO WET IN ARCTIC AIR
OUTBREAKS A 10 TO 1 SNOW WATER RATIO IS USED VERSUS SPLITTING THE
QPF IN HALF AND USING A 20 TO 1 RATIO WHICH PRODUCES THE SAME
SNOWFALL. THE ECM CONTINUES TO SHOW SOME FREEZING PCPN ACROSS SRN
NEB.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 554 PM CST SAT NOV 30 2013

OVER WESTERN NEBRASKA TONIGHT EXPECT INCREASING MID CLOUDS NORTH
WITH LIGHT AND VARIABLE WINDS. INCREASING CLOUDS SUNDAY WITH LIGHT
WESTERLY WINDS. VISUAL FLIGHT RULES.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...CDC
SHORT TERM...TAYLOR
LONG TERM...CDC
AVIATION...POWER