Gale Warning 318, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
435 PM AKDT TUE MAR 26 2013

.ANALYSIS AND UPPER LEVELS...
SKIES ARE CLEARING THIS AFTERNOON ACROSS THE SOUTHERN MAINLAND AS THE
NEGATIVELY TILTED UPPER LEVEL TROUGH THAT BROUGHT SIGNIFICANT
SNOWFALL TO SOUTHCENTRAL ALASKA YESTERDAY LIFTS NORTHWARD INTO THE
INTERIOR. A WEAKENING SURFACE LOW REMAINS OVER PRINCE WILLIAM
SOUND...SUPPORTING A FEW WEAK SNOW SHOWERS ALONG THE NORTHERN GULF
COAST AND CONTINUING GUSTY WINDS NEAR SEWARD AND WHITTIER.
MEANWHILE...A WEAK UPPER LOW SOUTH OF THE AKPEN IS MOVING SOUTHEAST
INTO THE NORTHERN PACIFIC WITH A WEAK FRONTAL BOUNDARY SUPPORTING
SNOW SHOWERS FROM THE AKPEN INTO THE EASTERN BERING AND A RAIN/SNOW
MIX FOR THE EASTERN ALEUTIANS. GUSTY WINDS ARE LEADING TO AREAS OF
BLOWING SNOW OVER THE PRIBILOFS...WITH BLIZZARD CONDITIONS ALREADY
BEING OBSERVED AT SAINT GEORGE ISLAND. A MUCH STRONGER UPPER LOW IS
DEVELOPING SOUTHEAST OF THE KAMCHATKA PENINSULA WITH AN ASSOCIATED
FRONT EXTENDING TO THE EAST WELL OUT AHEAD OF THE SURFACE
LOW...SPREADING SNOW SHOWERS AND GUSTY WINDS OVER THE WESTERN
ALEUTIANS.

.MODEL DISCUSSION...
MODELS REMAIN IN GOOD AGREEMENT THROUGH THE SHORT TERM WITH RESPECT
TO THE OVERALL SYNOPTIC PATTERN. THE MAIN FEATURE OF INTEREST THROUGH
THE REST OF THE WEEK WILL BE THE STRONG KAMCHATKA LOW THAT WILL
TRAVERSE THE ALEUTIAN CHAIN AS IT DEVELOPS INTO A BROAD LONGWAVE
TROUGH ENCOMPASSING THE ENTIRE BERING SEA BY THURSDAY. GREATER
DISCREPANCIES ARISE TOWARDS THE END OF THE WEEK AS THE AFOREMENTIONED
TROUGH APPROACHES THE WESTERN GULF. FOR THE SHORT TERM
FORECAST...UTILIZED A NAM/GFS BLEND TO HANDLE THE TIMING OF THE FRONT
AS IT MOVES THROUGH THE BERING.

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA...
SCATTERED SHOWERS ALONG THE GULF COAST WILL BE TAPERING OFF THIS
EVENING AS THE LOW OVER PRINCE WILLIAM SOUND CONTINUES TO WEAKEN AND
MOVES INLAND. THIS WILL ALSO ALLOW THE STRONG WINDS NEAR SEWARD AND
WHITTIER TO SUBSIDE AS THE PRESSURE GRADIENT WEAKENS. SKIES WILL
CONTINUE TO CLEAR THROUGH WEDNESDAY AS TRANSITORY UPPER LEVEL RIDGING
MOVES OVER SOUTHCENTRAL AK. THIS WILL ALLOW MANY INLAND LOCATIONS TO
DROP NEAR OR BELOW ZERO TONIGHT BEFORE TEMPERATURES BEGIN TO RECOVER
ON WEDNESDAY AHEAD OF THE NEXT SYSTEM. A FRONT WILL MOVE OVER THE
WESTERN GULF BY WEDNESDAY NIGHT...BRINGING A RAIN/SNOW MIX TO KODIAK
ISLAND AND THEN SPREADING SNOW TO THE NORTHERN GULF COAST ON
THURSDAY.

SOUTHWEST ALASKA...
COLD TEMPERATURES WILL PERSIST THROUGH TONIGHT AS HIGH PRESSURE MOVES
OVER THE SOUTHWEST MAINLAND...ALTHOUGH THE WIND CHILL CONCERNS OF THE
PREVIOUS SEVERAL DAYS WILL BE LIMITED AS WINDS HAVE GENERALLY
SUBSIDED. SNOW WILL RETURN TO THE AREA DURING THE DAY ON WEDNESDAY AS
THE FRONT ASSOCIATED WITH THE BERING LOW REACHES THE COAST. THE
ARRIVAL OF THE FRONT WILL BE ACCOMPANIED BY GUSTY WINDS...LEADING TO
AREAS OF BLOWING SNOW ...PARTICULARLY ALONG COASTAL PORTIONS OF THE
KUSKOKWIM DELTA AND THE WESTERN CAPES OF BRISTOL BAY. BLIZZARD
WATCHES HAVE BEEN ISSUED TO ACCOUNT FOR THESE CONCERNS. RAIN AND SNOW
WILL CONTINUE ALONG THE AKPEN ON WEDNESDAY AS THE FRONT MOVES
OVERHEAD.

ALEUTIANS/BERING SEA...
BLIZZARD CONDITIONS WILL INTENSIFY OVER THE PRIBILOFS THIS EVENING
AND LAST THROUGH WEDNESDAY MORNING AS SNOW PERSISTS AND WINDS
CONTINUE TO INCREASE AHEAD OF THE FRONT MOVING THROUGH THE BERING.
CONDITIONS WILL IMPROVE DURING THE DAY ON WEDNESDAY AS WINDS BEGIN TO
SUBSIDE AND TEMPERATURES WARM TO NEAR FREEZING. A MIX OF RAIN AND
SNOW WITH GUSTY WINDS WILL AFFECT THE ALEUTIANS THROUGH THE END OF
THE WEEK AS THE FRONT MOVES ACROSS THE CHAIN TONIGHT AND THEN THE LOW
ITSELF SKIRTS THE PACIFIC SIDE OF THE CHAIN WEDNESDAY MORNING THROUGH
FRIDAY.

.LONG TERM FORECAST...
EXTENDED TERM SENSIBLE WEATHER IMPACTS FOR SOUTHERN ALASKA LOOK TO BE
PREDOMINANTLY ASSOCIATED WITH THE DEEP LOW CURRENTLY LOCATED
SOUTHEAST OF THE KAMCHATKA PENINSULA AS IT DEVELOPS INTO A LONGWAVE
TROUGH AND APPROACHES THE GULF OF ALASKA THIS WEEKEND...WITH
PRECIPITATION IN THE FORECAST OVER COASTAL AREAS AND SCATTERED
SHOWERS INLAND. TEMPERATURES LOOK TO UNDERGO A MODERATING TREND LATER
THIS WEEK AS DEEP LAYER SOUTHERLY FLOW BECOMES ESTABLISHED OVER THE
SOUTHERN MAINLAND AHEAD OF THE BERING TROUGH.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 195
         BLIZZARD WATCH 155 161
MARINE...GALE WARNING 176 179 180 185
         HEAVY FREEZING SPRAY 121 127 128 129 130 140 179
FIRE WEATHER...NONE

CB MAR 13