Gale Warning 1081, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKST THU DEC 23 2010

.MODEL DISCUSSION...INITIALIZATIONS OF MSLP LOOK REASONABLE. SYNOPTIC
FORECAST TRENDS ARE IN GENERALLY GOOD AGREEMENT. HOWEVER...MODELS ARE
STILL STRUGGLING OVER THE GULF OF ALASKA AS SURFACE PRESSURE FIELD
BROADENS. THE NAM/ECMWF ARE PICKING UP A WAVE MOVING WEST ACROSS THE
NORTHERN GULF SAT. THE GFS IS LESS AGGRESSIVE ON THESE FEATURE.
ALTHOUGH THESE DIFFERENCES ARE PRESENT...THE TREND IS TO BRING
INCREASING CLOUDS AND A SHOT AT SNOW TO THE WESTERN/NORTHERN GULF
WITH LOWERING PRESSURES LATE FRI AND SAT.

.ANALYSIS...
.500 MB...WEAKENING TROUGH MOVING THROUGH SOUTHCENTRAL TO OVER THE
CENTRAL INTERIOR AND NORTH GULF THIS MORNING WILL STALL AS COLD AIR
PUSHES ACROSS THE EASTERN BERING SEA AND INTO THE NE PACIFIC TONIGHT
AND FRI. THIS SETS UP A RELATIVELY BROAD AND SOMEWHAT NEGATIVELY
TILTED TROUGH SAT NIGHT/SUN WITH THE TROUGH AXIS EXTENDING FROM FAR
NE PACIFIC..TO LOW OVER BRISTOL BAY/SW AK.

.SURFACE...
SOUTHCENTRAL ALASKA...STRONG PRESSURE AND THERMAL GRADIENTS ARE
EVIDENT ACROSS MUCH OF SOUTHCENTRAL ALASKA...ESPECIALLY THE NORTH
GULF COAST AND KENAI PENINSULA. WARNING LEVEL WIND GUSTS THROUGH
WHITTIER AND ACROSS THE VALDEZ ZONE (131) WHERE EVIDENT OVERNIGHT.
WINDS HAVE SINCE DIMINISHED BELOW WARNING LEVELS NEAR WHITTIER BUT
WILL REMAIN OVER ZONE 131 THROUGH THIS EVENING. PRESSURE GRADIENTS
WILL DIMINISH ACROSS MUCH OF SOUTHCENTRAL ALASKA OVERNIGHT AND SAT AS
AS PRESSURES RISE OVER THE GULF AND HIGH PRESSURE WEAKENS OVER THE
MAINLAND. THERMAL GRADIENTS WILL ALSO WEAKEN ACROSS THE GULF SAT WITH
WEAK WARM ADVECTION. ALTHOUGH WINDS WILL DIMINISH...EXPECT STRONG
WINDS THROUGH GAPS...ESPECIALLY THE GULF COAST INTO THE WEEKEND.
MOISTURE WILL SPREAD WEST ACROSS THE GULF FRI NIGHT AND SAT AS A LOW
CENTER TRACKS WEST ACROSS THE GULF. THE HIGHEST PROBABILITY OF SNOW
WILL BE ALONG THE COASTS...AND TO A LESSER EXTENT INLAND.

.SW ALASKA AND AK PEN...A WEAKEN FRONT MOVING ONSHORE OVER THE DELTA
LATE THIS AFTERNOON IS EXPECTED TO MOVE TO BRISTOL BAY AND STRETCH TO
THE AK PEN THIS EVENING. THE PORTION OF THE FRONT NORTH OF THE AK PEN
WILL STALL AND WEAKEN OVER BRISTOL BAY TONIGHT AND THE SOUTHERN
SECTION WILL CONTINUE TO PUSH SOUTH. OFFSHORE FLOW SETS UP OVER MUCH
OF SW ALASKA FRI AND CONTINUES INTO SUN. WINDS COMBINED WITH COLD
TEMPERATURE ADVECTION SHOULD PRODUCE LOW WIND CHILLS ACROSS MUCH OF
SW MAINLAND ON SAT AND SUN.

.ALEUTIANS...HIGH PRESSURE OVER THE CENTRAL ALEUTIANS WEAKENS AND
DRIFTS NORTH. A WEAK FRONTAL ZONE APPROACHING THE WEST ALEUTIANS WILL
PRODUCE STRONG EASTERLY WINDS ACROSS THE WEST ALEUTIANS FRI AND
SAT...THEN WEAKEN MON. BRISK NORTHERLY FLOW WILL CONTINUE OVER THE
EASTERN ALEUTIANS THROUGH THE WEEKEND AND SPREAD WESTWARD.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING ZONE 131.
MARINE...GALE 121 129 130 150 155 175 176
FIRE WEATHER...NONE.

RMC DEC 10