Brisk Wind Advisory 55, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 AM AKDT TUE APR 14 2009

.ANALYSIS AND UPPER LEVELS...
A 997 MB LOW SOUTH OF DUTCH HARBOR IS EVIDENT ON SATELLITE
IMAGERY...WITH AN ASSOCIATED FRONT STRETCHING NORTH ALONG THE AKPEN
AND INTO SOUTHCENTRAL ALASKA. THIS LOW IS EXPECTED TO WEAKEN WHILE A
COMPLEX LOW CENTER FORMS OVER THE GULF OF ALASKA. ELSEWHERE AT THE
SURFACE...HIGH PRESSURE IS BUILDING OVER THE WESTERN BERING SEA AND
WESTERN ALEUTIANS.

IN THE UPPER LEVELS...A HIGHLY AMPLIFIED PATTERN HAS SET UP ACROSS
THE AREA. A DEEP TROUGH EXTENDS OVER THE WESTERN MAINLAND THROUGH THE
EASTERN ALEUTIANS. AN ASSOCIATED CUT OFF LOW IS AT THE BASE OF THIS
TROUGH. A HIGHLY AMPLIFIED RIDGE IS BUILDING OVER THE WESTERN BERING
AND WESTERN AND CENTRAL ALEUTIANS.

.MODEL DISCUSSION...
MODELS HAVE COME INTO BETTER AGREEMENT IN HANDLING THE LOW COMPLEX
MOVING FROM THE NORTH PACIFIC INTO THE GULF OF ALASKA. CONSENSUS IS
GOOD THROUGH THURSDAY...WITH THE CHARACTERISTIC DIFFERENCES IN
INDIVIDUAL LOW PLACEMENT AND INTENSITY. THE GFS WAS AGAIN USED FOR
CONSTRUCTING THE MORNING FORECAST PACKAGE...WITH ONLY MINOR CHANGES
TO THE EXISTING FORECAST.

.SHORT TERM FORECAST...
.SOUTHCENTRAL...
SNOW AND RAIN ASSOCIATED WITH THE AFOREMENTIONED WEATHER FRONT IS
IMPACTING THE MAJORITY OF SOUTHCENTRAL THIS MORNING. A BLIZZARD
WARNING CONTINUES FOR PORTAGE VALLEY AND TURNAGAIN ARM...AS SNOW AND
STRONG EASTERLY WINDS CONTINUE TO REDUCE VISIBILITIES. SNOW ALONG
INTERIOR SECTIONS OF SOUTHCENTRAL WILL BE DECREASING THIS MORNING AS
INITIAL OVERRUNNING WANES. SNOW WILL CONTINUE THROUGH WEDNESDAY
MAINLY FOR COASTAL AREAS...WITH LOCATIONS ALONG THE IMMEDIATE COAST
MIXING WITH RAIN. WINDS THROUGH CHANNELED TERRAIN WILL BE DIMINISHING
TONIGHT AS THE GRADIENT RELAXES AND THE FRONT WEAKENS OVER THE
NORTHERN GULF. THE LOW COMPLEX IS STILL EXPECTED TO REMAIN NEARLY
STATIONARY OVER THE CENTRAL AND SOUTHERN GULF...KEEPING THE CHANCE OF
SHOWERS CONFINED MAINLY TO COASTAL LOCATIONS AS WE HEAD THROUGH
WEDNESDAY.

.SOUTHWEST...
PRECIPITATION ASSOCIATED WITH THE LOW COMPLEX WILL HAVE THE HIGHEST
IMPACT ALONG THE AKPEN AND BRISTOL BAY...WHERE RAIN AND SNOW WILL
CONTINUE THROUGH WEDNESDAY...ALONG WITH STRONG NORTHERLY FLOW.
UPSLOPE SNOW ALONG THE KUSKOKWIM VALLEY WILL LINGER THROUGH WEDNESDAY
BUT WILL GRADUALLY DIMINISH AS THE LOW IN THE GULF BECOMES DOMINANT
AND FLOW SWITCHES AROUND TO THE NORTH. CONDITIONS ACROSS THE
KUSKOKWIM DELTA WILL REMAIN DRY...ALTHOUGH GUSTY NORTHERLY WINDS CAN
BE EXPECTED ON THE BACKSIDE OF THE LOW.

.BERING SEA AND ALEUTIANS...
MAIN STORY IN THE NEAR TERM WILL BE THE WEAKENING LOW SOUTH OF DUTCH
HARBOR...AND STRONG NORTHERLY FLOW ON THE BACKSIDE OF THE DEVELOPING
GULF LOW COMPLEX. SNOW SHOWERS WILL BE MOST PREVALENT ACROSS THE
EASTERN ALEUTIANS AND PRIBILOFS TODAY...BUT WILL BE DIMINISHING AS WE
HEAD INTO TONIGHT. OTHERWISE EXPECT GUSTY NORTHERLY FLOW TO CONTINUE
OVER THE EASTERN ISLANDS THROUGH WEDNESDAY AS THE GRADIENT REMAINS
TIGHT. HIGH PRESSURE BUILDING OVER THE WESTERN AND CENTRAL ALEUTIANS
WILL RESULT IN GENERALLY FAIR WEATHER FOR THE NEXT SEVERAL DAYS.

.LONG TERM FORECAST...
EXPECT THE HIGHLY AMPLIFIED PATTERN TO REMAIN THROUGH THE END OF THE
WEEK...CHARACTERIZED BY A TROUGH OVER MAINLAND ALASKA AND A RIDGE
OVER THE BERING SEA AND ALEUTIANS. THIS WILL RESULT IN DRY OFFSHORE
FLOW FOR THE MAINLAND AND RELATIVELY TRANQUIL WEATHER ACROSS THE
ALEUTIANS. TEMPERATURES ARE ANTICIPATED TO REMAIN NEAR NORMAL THROUGH
THE END OF THE WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING...125
MARINE...GALE...120 130 132 138 155 165 170 171 172 179
         HEAVY FREEZING SPRAY...179
FIRE WEATHER...NONE

NRH APR 09