Brisk Wind Advisory 22, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKST SAT FEB 23 2013

.MODEL DISCUSSION...
GUIDANCE NOT IN PARTICULARLY GOOD AGREEMENT TODAY. ALTHOUGH THE
MODELS AGREE FAIRLY WELL ON THE PATTERN AND LOCATION OF MAJOR UPPER
LEVEL FEATURES...AFTER ABOUT 24 HOURS INTO THE FORECAST THEY DIVERGE
ON THE LOCATION OF IMPORTANT SURFACE FEATURES SUCH AS THE LOW IN
THE GULF OF ALASKA AND THE LOW SOUTH OF THE ALEUTIANS. DIVERGENCE
INCREASES BETWEEN THE NUMERICAL MODELS THROUGH 84 HOURS. THE
AFTERNOON FORECAST PACKAGE GENERALLY FOLLOWS THE ECMWF...WITH SOME
GFS USED IN THE FIRST 24 TO 36 HOURS.

.ANALYSIS AND UPPER LEVELS...
THE MAIN STEERING LOW IS CENTERED JUST TO THE WEST OF THE BERING
STRAIT. THERE ARE A COUPLE OF UPPER LEVEL LOWS IN THE SOUTHWESTERLY
FLOW ASSOCIATED WITH THIS STEERING LOW. ONE IS OVER SOUTHWEST ALASKA
AND MOVING SLOWLY NORTH THE OTHER IS OVER THE ALASKA PENINSULA
(AKPEN) AND MOVING EAST/NORTHEAST. A FRONT LOOSELY ASSOCIATED WITH
BOTH OF THESE LOWS IS CURRENTLY ALONG THE NORTH GULF COAST.

.SHORT TERM FORECAST...
SOUTH CENTRAL ALASKA...THE FRONT ALONG THE GULF COAST WILL MOVE
INLAND THIS EVENING BRINGING ELEVATED CHANCES OF PRECIPITATION
TO MOST AREAS. AS THE AKPEN LOW MOVES INTO THE GULF ON SUNDAY
ANOTHER SURGE OF MOISTURE WILL MOVE ACROSS THE AREA. AFTER SUNDAY
NIGHT...PRECIPITATION CHANCES WILL MAINLY BE LIMITED TO COASTAL
AREAS AS THE NEXT UPPER LOW THAT MOVES INTO THE GULF IS FURTHER
SOUTH.

SOUTHWEST ALASKA/ALEUTIAN ISLANDS/BERING SEA...THE MAIN STEERING LOW
JUST TO THE WEST OF THE BERING STRAIT WILL SLOWLY MIGRATE NORTHWEST
OVER THE NEXT FEW DAYS. A SERIES OF SYSTEMS WILL MOVE ACROSS THE
BERING SEA. THE GENERAL FORMULA WILL BE SYSTEMS DEVELOPING SOUTH OF
THE CENTRAL OR WESTERN ALEUTIANS THEN MOVING NORTHEAST ACROSS THE
AKPEN THEN EAST INTO THE GULF OF ALASKA. AREAS SUCH AS THE PRIBILOF
ISLANDS AND THE KUSKOKWIM DELTA WILL HAVE LOWER CHANCES OF
PRECIPITATION WITH THE HIGHEST CHANCES FROM THE ALEUTIANS ACROSS THE
AKPEN AND INTO BRISTOL BAY AND THE KUSKOKWIM VALLEY. ALTHOUGH THE
MODELS DISAGREE ON DETAILS...THEY ALL SHOW A RIDGE OVER THE EASTERN
BERING/EASTERN ALEUTIANS AND AKPEN MONDAY NIGHT AND TUESDAY FOR A
BRIEF BREAK FROM THE ACTIVE WEATHER PATTERN.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...WINTER WEATHER ADVISORY FOR BLOWING SNOW 195
MARINE...GALE WARNING 132 150 155 170 172.
         HEAVY FREEZING SPRAY 150 155 165 170 179.
FIRE WEATHER...NONE.

LUDWIG FEB 13