Heavy Freezing Spray Warning 174, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
100 PM AKDT TUE OCT 30 2012

.MODEL DISCUSSION...
GUIDANCE IN EXCELLENT AGREEMENT THROUGH THE SHORT TERM PORTION OF
THE FORECAST. GENERALLY USED THE NAM FOR ITS BETTER HANDLING OF THE
FINER DETAILS AND TERRAIN EFFECTS.

.ANALYSIS AND UPPER LEVELS...
THERE IS AN UPPER LEVEL LOW OVER SOUTHERN ALASKA CENTERED ABOUT OVER
PRINCE WILLIAM SOUND AND MOVING SLOWLY SOUTHWARD. THE UPPER LEVEL
RIDGE IS OVER EXTREME NORTHEAST RUSSIA. STRONG NORTHERLY FLOW ALOFT
OVER WESTERN ALASKA BENDS EASTWARD OVER THE GULF OF ALASKA AND INTO
THE PANHANDLE. TYPICAL COLD ADVECTION PATTERN AT THE SURFACE WITH
NORTHERLY WINDS IN MOST AREAS.

.SHORT TERM FORECAST...
FOR SOUTH CENTRAL...THE UPPER LEVEL LOW WILL DROP INTO THE GULF
TONIGHT AND THEN SLOWLY WORK TOWARDS THE SOUTHWEST WEDNESDAY THROUGH
THURSDAY. STRONG COLD ADVECTION AT THE LOW LEVELS WILL CONTINUE
THROUGH WEDNESDAY AND WEAKEN ON THURSDAY. CHANCES OF PRECIPITATION
WILL GENERALLY BE CONFINED TO THE GULF COAST AND TO HIGHER
ELEVATIONS OF THE COPPER RIVER BASIN TONIGHT THROUGH WEDNESDAY. A
STRONG STORM WILL DEVELOP OVER THE NORTHEAST PACIFIC AND MOVE INTO
THE SOUTHERN GULF OF ALASKA ON THURSDAY. THE SURFACE PRESSURE OF
THIS STORM IS EXPECTED TO DROP INTO THE 950S BY THURSDAY AFTERNOON
AND MAINTAIN THAT STRENGTH THROUGH FRIDAY.

FOR SOUTHWEST ALASKA AND THE ALEUTIANS/BERING SEA...NORTHERLY FLOW
ALOFT AND AT THE SURFACE WILL CONTINUE THROUGH FRIDAY AS THE RIDGE
OVER NORTHEAST RUSSIA AND THE TROUGH OVER THE GULF OF ALASKA REMAIN
BASICALLY IN PLACE.

.LONG TERM FORECAST...
FOR THE WEEKEND INTO EARLY NEXT WEEK THE BASIC PATTERN WILL REMAIN
THE SAME WITH A LOW OVER THE GULF OF ALASKA AND A RIDGE OVER
NORTHEAST SIBERIA. BY TUESDAY THE PATTERN SHOWS SIGNS OF BREAKING AS
THE SIBERIAN RIDGE BEGINS TO BREAK DOWN. GUIDANCE IS IN SURPRISINGLY
GOOD AGREEMENT FOR THE EXTENDED PORTION OF THE FORECAST.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...STORM WARNING 130.
         GALE WARNING 121 127 132 138 140 150 160 165 170 172 175
                       179 180.
FIRE WEATHER...NONE.

LUDWIG OCT 12