Heavy Freezing Spray Warning 206, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKST THU DEC 6 2012

.MODEL DISCUSSION...
GUIDANCE IN FAIRLY GOOD AGREEMENT ON THE DEVELOPMENT AND SPEED OF
THE UPCOMING NORTH PACIFIC LOW AND ITS ASSOCIATED FRONT(S). THE 12Z
ECMWF IS JUST A BIT FASTER THAN THE NAM AND GFS. GENERALLY WENT WITH
THE 12Z GFS FOR THE AFTERNOON FORECAST.

.ANALYSIS AND UPPER LEVELS...
THERE IS AN UPPER LEVEL LOW OVER SOUTHERN ALASKA WITH A LOBE
CENTERED NEAR BRISTOL BAY...ANOTHER OVER THE NORTHEASTERN GULF OF
ALASKA...AND A THIRD NEAR GALENA. THERE IS A DEVELOPING LOW SOUTH OF
THE ALEUTIANS AND MOVING NORTH...THIS LOW WILL BECOME A MAJOR PLAYER
IN THE WEATHER FOR THE WEEKEND FROM THE CENTRAL ALEUTIANS AND BERING
SEA THROUGH SOUTH CENTRAL ALASKA.

.SHORT TERM FORECAST...
THE GULF LOW WILL MOVE EAST...AND AFTER TONIGHT AND WILL NO LONGER
BE A PLAYER IN THE WEATHER FOR SOUTH CENTRAL ALASKA. THE BRISTOL BAY
LOW WILL MOVE NORTH TONIGHT AND MERGE WITH THE GALENA LOW ON FRIDAY.

THE LOW SOUTH OF THE ALEUTIANS WILL RAPIDLY SPIN UP TONIGHT AND BE
WELL DEVELOPED BY FRIDAY MORNING WITH A SURFACE LOW BELOW 970
MB...WHICH WILL DROP INTO THE MID 950'S BY FRIDAY EVENING.

FOR SOUTHWEST ALASKA...THE OCCLUDED FRONT WILL REACH THE CENTRAL AND
EASTERN ALEUTIANS AS WELL AS THE ALASKA PENINSULA (AKPEN) FRIDAY
EVENING. BLIZZARD CONDITIONS ARE POSSIBLE FOR THE EASTERN ALEUTIANS
AND AKPEN IN THE PRE-FRONTAL AREA AS THE WINDS INCREASE AND BEFORE
THE WARM AIR PUSHES IN WITH THE FRONT. WARMER AIR WILL ARRIVE BY
SATURDAY MORNING WITH THE PRECIPITATION SWITCHING TO RAIN.

AS THE FRONT MOVES NORTH INTO THE BERING SEA ON SATURDAY THE
PRIBILOFS LOOK TO BE IN A FAVORABLE POSITION FOR BLIZZARD CONDITIONS
INTO THE EVENING HOURS.

THE SOUTHWEST MAINLAND WILL ALSO BE UNDER THE GUN ON SATURDAY.
BLIZZARD CONDITIONS ARE POSSIBLE FROM DILLINGHAM NORTH. AS WARMER
AIR ALOFT MOVES IN DURING THE DAY THERE WILL BE A CHANCE OF FREEZING
RAIN FOR LOW-LYING AREAS OF THE ZONE.

FOR SOUTH CENTRAL ALASKA...THE WARM FRONT ASSOCIATED WITH THE
ALEUTIAN LOW WILL MOVE INTO THE NORTHERN GULF SATURDAY MORNING
AND TO THE NORTHERN GULF COAST SATURDAY EVENING. PRECIPITATION
ASSOCIATED WITH THIS FRONT WILL SPREAD INLAND DURING THE DAY. THE
HEAVIEST SNOWFALL WILL BE IN THE EASTERN KENAI PENINSULA.

FOR THE ANCHORAGE AREA AND MATANUSKA VALLEY...SOME SNOW IS EXPECTED
INLAND WITH THE INITIAL WARM ADVECTION SATURDAY AFTERNOON INTO
SATURDAY NIGHT...THEN DIMINISH TO SCATTERED SHOWERS ON SUNDAY.

.LONG TERM FORECAST...
THE MAIN LOW WILL MOVE INLAND SUNDAY NIGHT OVER SOUTHWEST ALASKA
AND RAPIDLY WEAKEN. THIS LOW WILL MOVE OUT OF ALASKA BY LATE TUESDAY
MORNING. A TRANSIENT RIDGE OF HIGH PRESSURE WILL BE OVER SOUTHERN
ALASKA ON TUESDAY AS A LARGE UPPER LOW SETTLES IN OVER THE BERING
SEA. ACTIVE WEATHER WILL RETURN ON WEDNESDAY AND THURSDAY TO
SOUTHERN AS SYSTEMS SPIN OFF THE BERING LOW AND RACE EASTWARD.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WATCH 155 161 181 185 195.
MARINE...STORM WARNING 170 172.
         GALE WARNING 127 132 150 155 160 165 171 175 179.
         HEAVY FREEZING SPRAY 126 127 160 165 179 185.
FIRE WEATHER...NONE.

LUDWIG DEC 12