Snow Advisory 20, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
540 PM AST WED NOV 7 2007

.MODEL DISCUSSION...THE GFS MODEL SEEMS TO BE THE MOST CONSISTENT
CHOICE. PREFER HOW THE GFS/UKMET HANDLES TRIPLE POINT DEVELOPMENT
OVER THE SOUTHERN GULF THU NIGHT AND MOVES TO THE NORTHERN GULF FRI
AFTN/NIGHT. GFS INITIALIZATION ON CURRENT CENTERS OVER BRISTOL BAY
AND NEXT STORM SOUTH OF THE ALEUTIANS IS VERY GOOD. GFS IS FAIRLY
CONSISTENT WITH STORM ENTERING THE SOUTHERN GULF SAT NIGHT...THOUGH
THIS RUN IS A LITTLE SLOWER AND SLIGHTLY DEEPER. MODELS STILL HAVING
PROBLEMS IN THE MID-LONG TERM WITH SOLUTIONS OVER THE BERING SEA.

.SYNOPSIS...
980S LOW OVER SW ALASKA THIS AFTERNOON MOVES OVER THE INTERIOR
TONIGHT AND WEAKENS. ASSOCIATED FRONTAL TROUGH EXTENDING OVER THE
DELTA...KUSKOKWIM VALLEY...SOUTHERN COOK INLET...TO OVER KODIAK
ISLAND MOVES THROUGH NORTH AND EAST TONIGHT. EXPECT FRONT WILL MOVE
TO THE COPPER RIVER BASIN/NORTH GULF COAST AFTER MIDNIGHT AND
DISSIPATE OVER CANADA THU. 970S LOW CENTER SOUTH OF 50N 172W THIS
AFTERNOON DEEPENS INTO THE 960S AS IT CROSSES UNALASKA EARLY THU
MORNING. CENTER WILL MOVE SE OF CAPE NEWENHAM IN THE UPPER 950S/LOWER
960S FRI. CENTER LIKELY AND DRIFT NEAR KODIAK ISLAND AS A TRIPLE
POINT LOW MOVES INTO THE NORTHERN GULF FRI NIGHT. FRONTAL TROUGH
ASSOCIATED ALEUTIAN LOW MOVES TO SOUTH OF THE PRIBILOF ISLANDS AND
OVER THE CENTRAL AK PEN EARLY THU MORNING AND INTO SW ALASKA/SOUTHERN
COOK INLET...TO OVER KODIAK THU AFTERNOON. FRONT STALLS OVER
SOUTHCENTRAL ALASKA THU/THU NIGHT AS A TRIPLE POINT CENTER DEVELOPS
OVER THE SOUTHERN GULF.

.SHORT TERM FORECAST...
.EAST...EXPECT SNOW AND RAIN WITH AS FRONTAL TROUGH MOVES THROUGH
SOUTHCENTRAL TONIGHT. RAIN MAINLY ALONG COASTAL AREAS AND THE KENAI
PEN. EXPECT FAIR SNOW AMOUNTS OVER THE SUSITNA VALLEY AND ZONE 131
WITH FRONTAL TROUGH AND SOUTHERNLY SLOW IN THE LOW AND MID LEVELS.
MAY SEE BRIEF DRYING THU MORNING BEFORE APPROACHING FRONT BRINGS
RAIN/SNOW TO COASTAL AREAS THU AFTERNOON.

GUSTY GAP WINDS OVER SOUTHCENTRAL TODAY WILL DIMINISH AFTER FRONTAL
PASSAGE TONIGHT. HOWEVER...GUSTY SOUTHERLY WINDS LIKELY OVER THE
COPPER RIVER BASIN THROUGH TONIGHT. STRONG GUSTY WINDS DEVELOP AGAIN
OVER SOUTHCENTRAL ALASKA/GULF THU AND CONTINUE INTO FRI MORNING.

.WEST...SNOW AND RAIN WILL TAPER OFF TONIGHT AS LOW AND ASSOCIATED
FRONTAL TROUGH CLEAR SW ALASKA TONIGHT. STRONG WIND CONDITIONS WILL
DEVELOP OVER UNALASKA BY EVENING AND SPREAD TO THE AK PEN AND BRISTOL
BAY OVERNIGHT. WINDY CONDITIONS LIKELY TO HOLD OVER MUCH OF THE EAST
ALEUTIANS..AK PEN..SW ALASKA...AND BRISTOL BAY THROUGH FRI. THE MORE
SIGNIFICANT WINDS THU AND FRI WILL BE ON THE WEST AND SOUTHERN FLANKS
OF THE LOW OVER BRISTOL BAY. APPROACHING FRONT BRINGS RAIN TO
UNALASKA THIS AFTERNOON AND THE AK PEN TONIGHT. EXPECT RAIN AND SNOW
TO SPREAD TO THE BRISTOL BAY COAST EARLY THU. PRECIPITATION MAY
INITIALLY START AS SNOW OVER BRISTOL...BUT SHOULD RAPIDLY CHANGE OVER
TO RAIN OR MIX WITH WARM ADVECTION THU. SNOW OVER THE DELTA THU WILL
LIKELY MIX WITH RAIN IN THE AFTERNOON. PRECIPITATION SHOULD BREAK UP
INTO SNOW SHOWERS(EXCEPT RAIN/SNOW BRISTOL BAY) OVER MOST OF SW
ALASKA THU NIGHT AND FRI.

.LONG TERM FORECAST...LIKELY CHANGE FROM PREVIOUS FORECAST AT THIS
POINT.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...STORMS...155 165 170.
         GALES 120 130 132 138 140 141 150 160 171 172 179 180 185.
FIRE WEATHER...NONE.

RMC NOV 07