FXAK68 PAFC 141514 CCA
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION...CORRECTION
NATIONAL WEATHER SERVICE ANCHORAGE AK
500 AM AKST THU FEB 14 2013

CORRECTED WATCH/WARNING SUMMARY
.ANALYSIS AND UPPER LEVELS...
A STRENGTHENING LOW CURRENTLY SOUTH OF KODIAK ISLAND IS MOVING
NORTHWARD INTO THE WESTERN GULF. NORTHWEST OF THIS LOW A DEVELOPING
DEFORMATION ZONE IS PRODUCING SNOW SHOWERS FROM THE KUSKOKWIM DELTA
TO ALASKA PENINSULA. NORTH OF THE KODIAK LOW A BARRIER JET STRETCHES
FROM PRINCE WILLIAM SOUND TO THE NORTHERN PANHANDLE. THIS BARRIER JET
WILL INTENSIFY TODAY IN RESPONSE TO THE APPROACHING LOW FROM THE
SOUTH. ANOTHER LOW IS CURRENTLY WELL SOUTHWEST OF THE ALEUTIANS...AND
WILL BEGIN IMPACTING THE WESTERN CHAIN ON FRIDAY MORNING.
.MODEL DISCUSSION...
THE MODELS ARE IN MUCH BETTER AGREEMENT TODAY IN THE SHORT TERM THAN
YESTERDAY. SPECIFICALLY THE NAM IS HANDLING THE LOW NEAR KODIAK
ISLAND MUCH BETTER TODAY...SO IT WAS ABLE TO BE USED MORE FOR TODAYS
MORNING PACKAGE THAN IN PREVIOUS DAYS. HOWEVER CLOSER EXAMINATION OF
SATELLITE AND MIDDELTON RADAR SHOW THAT THE MODELS ARE ROUGHLY 3
HOURS TOO SLOW TO BRING LOW INTO THE GULF. THERE IS GOOD AGREEMENT
THAT THIS SYSTEM WILL MAKE LANDFALL JUST EAST OF SEWARD TOMORROW
MORNING...ON NEARLY AN IDENTICAL TRACK TO THE LOW THAT PASSED THROUGH
YESTERDAY.
.SHORT TERM FORECAST...
.SOUTHCENTRAL...MOST OF SOUTHCENTRAL WILL SEE A SHORT PERIOD OF QUIET
WEATHER TODAY BEFORE THE APPROACHING LOW NEAR KODIAK BEGINS AFFECTING
COASTAL AREAS LATER THIS MORNING...FOLLOWED BY THE INTERIOR AREAS OF
SOUTHCENTRAL THIS EVENING. ANCHORAGE AND THE MATANUSKA VALLEY WILL BE
INITIALLY DOWNSLOPED THROUGH THIS EVENING...BUT THEN A BETTER CHANCE
FOR ACCUMULATING SNOW WILL MOVE IN LATE TONIGHT AS THE SOUTHEAST
WINDS ALOFT DIMINISH. THE HEAVIEST SNOWFALL FOR ANCHORAGE WILL OCCUR
FRIDAY MORNING AS AN UPPER LEVEL WAVE MOVES IN FROM THE WESTERN
INTERIOR. AT THIS POINT IT APPEARS THAT ANCHORAGE WILL STAY JUST
BELOW ADVISORY LEVEL SNOWFALL...BUT THAT WILL NEED TO BE MONITORED AS
THE SYSTEM DEVELOPS TODAY.
.SOUTHWEST...THE DEFORMATION ZONE CONTINUES TO PRODUCE AN AREA OF
SNOW OVER THE EASTERN KUSKOKWIM DELTA AND LOWER KUSKOKWIM VALLEY.
THIS ZONE WILL BEGIN TO DIMINISH THIS EVENING AS THE UPPER LEVEL LOW
SHIFTS TO THE EAST. A WEAKENING LOW THAT PASSED THROUGH THE ALASKA
PENINSULA LAST NIGHT WILL PRODUCE SNOW SHOWERS FOR BRISTOL BAY
THROUGH THIS EVENING. THE HIGHEST ACCUMULATION FROM THESE SYSTEMS
WILL OCCUR IN THE LOWER KUSKOKWIM VALLEY AND BRISTOL BAY...WHERE UP
TO 3 INCHES OF ACCUMULATION IS POSSIBLE.  
.BERING SEA AND ALEUTIANS...NORTH WINDS AND SNOW SHOWERS WILL PREVIAL
TODAY FOR THE EASTERN BERING AND ALEUTIANS TODAY. THE WESTERN
ALEUTIANS ON THE OTHER HAND WILL BEGIN TO BE AFFECTED BY THE
APPROACHNG ALEUTIAN LOW STARTING LATE THIS WEEKEND...WHICH WILL THEN
SPREAD THROUGHOUT THE ALEUTIANS THIS WEEKEND. THIS SYSTEM WILL STAY
COLD ENOUGH FOR SNOW UNTIL FRIDAY NIGHT WHEN RAIN WILL BEGIN MIXING
IN OVER THE CENTRAL ALEUTIANS.
.LONG TERM FORECAST...
MODEL DISAGREEMENTS IN THE LONG RANGE CONTINUE TO BE IMPACTED BY A
SIBERIAN RIDGE SLIDING INTO THE BERING. THIS WILL PREVENT THE
EASTWARD PROGRESSION ON THE ALEUTIAN LOW TRACK STARTING SUNDAY. THERE
IS ALSO GOOD MODEL AGREEMENT THAT THIS RIDGE WILL THEN MOVE OVER TO
THE WESTERN MAINLAND...WHICH WILL LOOKS TO BRING CLEAR AND COOLER
WEATHER TO THE SOUTHWEST MAINLAND EARLY NEXT WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...STORM...120 352
         GALE...130 140 155 160 165 170 171 172 175 176 351 411 412  
                413
         HEAVY FREEZING SPRAY...130 138 140 150 155 160 165 170 171  
                                179 412 413 414
FIRE WEATHER...NONE

DEK FEB 13