Blizzard in Alaska, April 3 to 5, 2012

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
500 AM AKDT TUE APR 3 2012

.MODEL DISCUSSION...
MODELS IN GENERALLY GOOD AGREEMENTS AND INITIALIZED FAIRY WELL. IN
THE WEST THE MODELS INITIALLY DO WELL WITH THE PACIFIC LOW TRACKING
TOWARD DUTCH HARBOR BY WEDNESDAY BUT BEGIN HAVING SOME MINOR PROBLEMS
BEYOND THAT. THE ECMWF WAS THE PREFERRED BUT WITH THIS LAST RUN IT
HAS COME IN AGREEMENT WITH THE GFS ESPECIALLY WITH THE NEXT SYSTEM
MOVING IN FROM OUT WEST. MORNING FORECASTS MAINLY A BLEND OF THE GFS
AND ECWMF OUT WEST AND THE NAM IN THE EAST.

.ANALYSIS AND UPPER LEVELS...
A RIDGE OF HIGH PRESSURE CENTERED OVER THE BRISTOL BAY AREA WILL
CONTINUE TO BUILD IN OVER THE GULF AS IT DRIFTS TO THE EAST THE NEXT
COUPLE OF DAYS. A DEEPENING LONG WAVE TROUGH CENTERED OVER THE
WESTERN ALEUTIAN WILL MAKE ITS WAY ACROSS THE BERING THROUGH
WEDNESDAY WHILE WEAK RIDGING BUILDS IN BEHIND IT. AT THE SURFACE AN
OLD CUT-OFF CENTER SOUTHEAST OF THE GULF WILL DRIFT OFF TO THE
SOUTHEAST AND WEAKEN OUT OF THE AREA TODAY. WEAK HIGH PRESSURE IS
MOVING IN OVER THE MAINLAND. A WEAKENING OCCLUDED FRONT OVER THE
CENTRAL BERING SEA IS MOVING SLOWLY EAST AND SHOULD CONTINUE TO
WEAKEN AS IT APPROACHES THE PRIBILOFS THIS AFTERNOON.

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA...
WITH A LIGHT NORTHERLY FLOW OVER MOST AREAS EXPECT RELATIVELY FAIR
SKIES OVER MOST AREAS TODAY. AREAS OF FOG OVER COOK INLET AND THE
ANCHORAGE BOWL WILL CONTINUE TO BE A PROBLEM THIS MORNING. OTHER
THAN THAT EXPECT MOSTLY CLEAR SKIES TO CONTINUE OVERNIGHT. AS THE
FRONTAL TROUGH MOVES IN FROM THE WEST EXPECT INCREASING CLOUDS IN
THE WEDNESDAY MORNING WITH A CHANCE OF RAIN OR SNOW BY WEDNESDAY
AFTERNOON OVER THE WESTERN HALF OF SOUTHCENTRAL.

SOUTHWEST...
WEAK SOUTHWEST FLOW ALONG THE COASTAL AREAS SHOULD BRING LOW CLOUDS
AND FOG ACROSS THE REGION. AS THE LOW DRIFTS EAST FROM THE CENTRAL
ALEUTIANS ALONG WITH ITS ASSOCIATED FRONT EXPECT RAIN AND SNOW LATE
THIS AFTERNOON AND EVENING TO SPREAD ACROSS THE ALASKA PENINSULA.

ALEUTIANS/EASTERN BERING SEA...
A DEVELOPING LOW OVER THE WESTERN NORTH PACIFIC INTENSIFIES AS IT
APPROACHES THE CENTRAL ALEUTIANS THIS MORNING. THIS LOW WILL THEN
TRACK TO THE EAST AND BEGIN TO WEAKEN AS IT NEARS THE SOUTHWEST COAST
BY WEDNESDAY NIGHT. EXPECT BLIZZARD CONDITIONS OVER THE PRIBILOFS BY
LATE THIS AFTERNOON AS THE FRONTAL TROUGH APPROACHES. BLOWING SNOW
AND STRONG WINDS OVER THE CENTRAL ALEUTIANS ARE EXPECTED TODAY AS THE
LOW AND THE BENT BACK OCCLUDED FRONT MOVE INTO THE AREA. CONDITIONS
SHOULD IMPROVE TONIGHT AS THE LOW MOVES EAST AND WEAKENS.

.LONG TERM FORECAST...
THE RIDGE OF HIGH PRESSURE OVER THE GULF OF ALASKA WILL SHIFT TO THE
EASTERN GULF BY WEDNESDAY ALLOWING THE UPPER TROUGH ALONG WITH THE
SURFACE FRONT WILL BRING LIKEY RAIN AND SNOW TO THE COASTAL AREAS BY
THURSDAY WITH A CONTINUED CHANCE OF PRECIPITATION INLAND. A STRONG
FRONT WILL CROSS THE BERING PUSHING UP AGAINST THE SOUTHWEST COAST BY
SATURDAY. EXPECT RAIN AND SNOW AHEAD OF THE FRONT AS IT MOVES ACROSS
THE BERING/ALEUTIANS THROUGH MUCH OF THE WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 195.
MARINE...STORMS..172 175.
         GALES...179.
FIRE WEATHER...NONE.

APR 12