Gale Warning 132, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
620 AM AKST WED FEB 20 2013

.ANALYSIS AND UPPER LEVELS...
IN THE UPPER LEVELS...A RIDGE IS PARKED OVER THE CHUKCHI SEA WITH A
CLOSED LOW TO THE SOUTHWEST OF IT ALONG EASTERN RUSSIA. THIS LOW
PRESSURE SYSTEM IS SENDING WAVES OF ENERGY FROM THE NORTH TO
NORTHEASTERN PACIFIC. ONE LOW CENTER IS OVER THE ALASKA PENINSULA AND
ANOTHER IS JUST SOUTH OF IT. AT THE SURFACE...THERE IS A WEAKENING
SURFACE FRONT ALONG THE NORTHERN GULF OF ALASKA. EAST OF
KODIAK...THERE IS A 980 MB LOW AND ANOTHER IS SOUTHEAST OF SAND
POINT. FURTHER WEST...A SURFACE LOW IS NORTH OF SHEMYA. THESE SURFACE
FEATURES ARE BRINGING LIGHT SNOW ACROSS SOUTH ALASKA AND THE ALEUTIAN
CHAIN. WITH A  TIGHTER GRADIENT NORTH OF THE SURFACE LOW NEAR
KODIAK...NORTHERLY WINDS ARE GUSTY ALONG THE NORTHERN GULF COAST OF
ALASKA AND INLAND.

.MODEL DISCUSSION...
THE CURRENT WEATHER REGIME IS COMPLICATED WITH MULTIPLE WAVES SENT
ACROSS THE NORTHERN PACIFIC. MODELS HAVE SLIGHT VARIATIONS IN TIMING
AND PLACEMENT IN PRECIPITATION...HOWEVER THE UPPER LOW OFF OF RUSSIA
IS THE DOMINANT PATTERN THROUGH THE SHORT TERM AND THIS WILL BRING
PERIODS OF SNOW AND RAIN. THE PREFERRED MODELS IN THE SHORT TERM
WERE THE NAM AND...ACROSS SOUTHWEST ALASKA AND THE BERING...A
COMBINATION OF THE GEM GLOBAL AND ECMWF.

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA...
THE BLIZZARD WARNING IS CANCELED FOR WESTERN PRINCE WILLIAM SOUND AS
CONDITIONS HAVE IMPROVED. WINDS HAVE STARTED TO DIMINISH...HOWEVER
BLOWING SNOW WILL REDUCE VISIBILITIES TO ONE MILE AT TIMES DURING THE
MORNING THROUGH PORTAGE VALLEY.

THE SURFACE LOWS...NEAR KODIAK AND THE ALASKA PENINSULA...WILL MOVE
INTO THE GULF TODAY AND MERGE TOGETHER. THIS LOW WILL BECOME
STATIONARY IN THE NORTHERN GULF AND SLOWLY SPREAD PRECIPITATION
INLAND ACROSS SOUTHEAST AND SOUTHCENTRAL ALASKA THROUGH THURSDAY
NIGHT. THE LOW WILL WEAKEN ON FRIDAY AND PRECIPITATION WILL TAPER
OFF. PRECIPITATION WILL MAINLY BE SNOW EXCEPT FOR RAIN MIXING ALONG
THE COASTAL AREAS. THE NEXT FRONT WILL MOVE INTO THE WESTERN GULF
FRIDAY NIGHT.

SOUTHWEST ALASKA...
SNOW ALONG THE BACKSIDE OF THE LOW NEAR KODIAK WILL CONTINUE ACROSS
BRISTOL BAY AND THE ALASKA PENINSULA TODAY. SNOW WILL MOVE NORTH
TONIGHT INTO THE KUSKOKWIM VALLEY AND DELTA. MOST OF THE SNOW WILL
TAPER OFF FRIDAY MORNING AS THE LOW MOVES FURTHER EAST. THE NEXT
FRONT WILL MOVE INTO THE ALASKA PENINSULA LATE FRIDAY NIGHT. THIS
SYSTEM WILL CONTINUE TO SPREAD SNOW NORTHWARD THROUGH THE EARLY PART
OF THE WEEKEND.

ALEUTIANS/BERING SEA...
WEAK LOW PRESSURE WILL BRING PERIODS OF SNOW AND RAIN SHOWERS THROUGH
FRIDAY NIGHT. THE NEXT SIGNIFICANT STORM SYSTEM WILL MOVE INTO THE
WESTERN AND CENTRAL ALEUTIANS FRIDAY NIGHT AND SATURDAY.

.LONG TERM FORECAST...
AN ACTIVE WEATHER PATTERN WILL CONTINUE THROUGH THE LONG TERM
FORECAST. THE UPPER RIDGE IN THE CHUKCHI SEA WILL ADVECT COLDER AIR
ACROSS THE BERING AND SOUTH ALASKA...THEREFORE COLDER THAN NORMAL
TEMPERATURES WILL CONTINUE.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALES 120 132 150 155 170 172 175
         HEAVY FREEZING SPRAY 165
FIRE WEATHER...NONE.

KH FEB 20