Brisk Wind Advisory 12, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKST SAT FEB 2 2013

.MODEL DISCUSSION...
GUIDANCE IN FAIRLY GOOD AGREEMENT THROUGH THE SHORT TERM PORTION OF
THE FORECAST. THERE ARE SOME SUBTLE DIFFERENCES IN THE TIMING AND
POSITION OF THE LOW NEAR THE EASTERN ALEUTIANS/ALASKA PENINSULA
(AKPEN) AND THE FRONT MOVING INTO THE NORTHERN GULF ON SUNDAY...BUT
NOT ENOUGH TO HAVE BIG IMPACTS ON THE FORECAST. FOR MONDAY NIGHT
THERE ARE DIFFERENCES IN HOW THEY HANDLE A LOW DEVELOPING ON A FRONT
STRETCHED ACROSS THE ALEUTIANS WITH THE GFS BEING A LITTLE FASTER
AND STRONGER THAN THE ECMWF...WHILE THE NAM IS IN BETWEEN ON SPEED
AND HAS THE DEEPEST SURFACE LOW.

.ANALYSIS AND UPPER LEVELS...
THE MAJOR LONG-WAVE FEATURES ARE AN UPPER LEVEL LOW CENTERED JUST
SOUTH OF UNALASKA WITH A TROUGH STRETCHING NORTHWEST INTO
NORTHEASTERN RUSSIA...AND A NEGATIVELY TILTED RIDGE ALONG THE NORTH
AMERICAN WEST COAST THROUGH NORTHERN ALASKA. A WEATHER FRONT
ASSOCIATED WITH THE LOW STRETCHES FROM ABOUT DUTCH HARBOR EASTWARD
INTO THE CENTRAL GULF OF ALASKA AND THEN BENDS SOUTHWARD. A WEAKER
FRONT IS JUST ONSHORE ALONG THE NORTHERN GULF COAST.

.SHORT TERM FORECAST...
SOUTH CENTRAL ALASKA...A WEAK FRONT ALONG THE NORTH GULF COAST WILL
WASH OUT TONIGHT WITH MOST OF THE PRECIPITATION ASSOCIATED WITH THIS
FEATURE CONFINED TO COASTAL AREAS. THE NEXT STRONGER FRONT WILL
REACH KODIAK THIS EVENING AND THE NORTH GULF COAST LAT TONIGHT. THIS
SYSTEM WILL ALSO WEAKEN SIGNIFICANTLY AFTER HITTING THE COAST...BUT
WILL MOVE INLAND PROVIDING ELEVATED CHANCES OF PRECIPITATION SUNDAY
AFTERNOON AND EVENING. AFTER THIS THE WEATHER WILL BE FAIRLY QUIET
THROUGH TUESDAY AS THE MAIN UPPER LOW CURRENTLY SOUTH OF UNALASKA
SPLITS INTO TWO WEAKER LOWS...ONE MOVING INTO SOUTHWEST ALASKA AND
THE OTHER INTO THE SOUTHERN GULF OF ALASKA.

SOUTHWEST ALASKA...THE FRONT OVER THE AKPEN THIS EVENING WILL MOVE
INTO SOUTHWEST ALASKA LATER TONIGHT AS IT CONTINUES TO WEAKEN...THEN
WILL DISSIPATE SUNDAY AFTERNOON. THE UPPER LOW CURRENTLY SOUTH OF
UNALASKA WILL SPLIT LATER SUNDAY...WITH THE NORTHERN PORTION OF THE
SPLIT MOVING INTO SOUTHWEST ALASKA ON MONDAY. THIS WILL BRING COOLER
AIR INTO THE BRISTOL BAY AREA AND ELEVATED CHANCES OF SNOW INTO ALL
OF MAINLY SOUTHWEST ALASKA.

THE ALEUTIANS AND BERING SEA...
AS THE UPPER LOW SOUTH OF UNALASKA MOVES EASTWARD TONIGHT...SOME
WRAP-AROUND MOISTURE WILL CROSS THE PRIBILOFS. THIS WILL COMBINE
WITH THE ALREADY STRONG WINDS FOR BLIZZARD CONDITIONS. THESE
CONDITIONS WILL EASE UP ON SUNDAY AS THE WINDS AND SNOWFALL ABATE.
AN UPPER LEVEL RIDGE OF HIGH PRESSURE THAT IS CURRENTLY BUILDING
INTO THE WESTERN BERING SEA WILL THEN SLIDE EASTWARD ACROSS THE
CENTRAL BERING SEA ON MONDAY. A WEATHER FRONT WILL MOVE INTO THE
WESTERN ALEUTIANS LATE SUNDAY AND INTO THE CENTRAL ALEUTIANS ON
MONDAY. THIS FRONT WILL THEN STALL ON MONDAY AS THE ALEUTIAN RIDGE
HOLDS IN PLACE AND THEN BREAK APART MONDAY NIGHT. ANOTHER STRONGER
SYSTEM WILL MOVE INTO THE WESTERN ALEUTIANS ON TUESDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WATCH 195.
MARINE...GALE WARNING 120 130 138 140 150 155 170 172 175 176 179.
         HEAVY FREEZING SPRAY 179 185.
FIRE WEATHER...NONE.

LUDWIG FEB 13