Gale Warning 275, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
545 AM AKST MON MARCH 7 2011

.UPPER LEVEL/SURFACE ANALYSIS...HIGH PRESSURE REMAINS FIRMLY IN
CONTROL OVER MUCH OF MAINLAND ALASKA THIS MORNING. THE REMNANTS OF A
SURFACE LOW ARE BRINGING RAIN AND SNOW SHOWERS TO KODIAK ISLAND AND
THE AKPEN AS IT WORKS ITS WAY WEST OUT OF THE GULF OF ALASKA. THE
SUPPORTING UPPER LEVEL LOW CENTER HAS OPENED UP INTO A BROAD WAVE
THAT IS CROSSING THE AKPEN INTO THE SOUTHERN BERING SEA...BRINGING A
FEW SHOWERS AS WELL.

TO THE WEST THE LOW SOUTH OF THE ALEUTIANS IS RAPIDLY WEAKENING ALONG
WITH ITS ASSOCIATED FRONTAL BOUNDARY THAT STRETCHES ACROSS THE
EASTERN ALEUTIANS NORTHWESTWARD ACROSS THE CENTRAL BERING. LIGHT RAIN
IS CURRENTLY BEING REPORTED IN THE EASTERN ALEUTIANS ALONG THIS
DECAYING FRONT.

.MODEL DISCUSSION...MODELS HAVE COME INTO VERY GOOD AGREEMENT
REGARDING SYNOPTIC FEATURES THROUGH 84 HOURS WITH THE NAM BEING
PREFERRED FOR ITS GREATER DETAIL. THE ECMWF AND GFS CONTINUE TO
EXHIBIT DIFFERENCES IN THE MEDIUM TO LONG RANGE. THE GFS CONTINUES TO
ATTEMPT TO PUSH THE UPPER LEVEL RIDGE OVER THE BERING STRAIT EASTWARD
WHILE BRINGING A LARGE LOW INTO THE WESTERN ALEUTIANS THU NIGHT INTO
FRI. THE ECMWF MEANWHILE KEEPS THE RIDGE FIRMLY IN PLACE...KEEPING
LOW TRACKS MAINLY SOUTH OF THE ALEUTIANS. THE GEM MODEL IS GENERALLY
IN BETWEEN THE TWO. THE EXTENDED FORECAST CONTINUES TO LEAN TOWARDS
THE ECMWF SOLUTION.

.SHORT TERM FORECAST...
.SOUTHCENTRAL ALASKA...SUNNY AND DRY WILL BE THE RULE THIS WEEK AS
HIGH PRESSURE CONTINUES TO DOMINATE THE STATE. THE EXCEPTION TO THIS
WILL BE KODIAK ISLAND WHERE THE UPPER LEVEL TROUGH AND ONSHORE FLOW
WILL CONTINUE TO BRING RAIN AND SNOW SHOWERS TO THE ISLAND. A FEW
SHOWERS MAY ALSO CLIP THE SOUTHERN KENAI. SHOWERS WILL LIKELY TAPER
OFF TONIGHT ACROSS THE WESTERN GULF AS THE UPPER TROUGH MOVES OUT OF
THE AREA...HOWEVER CHANCE POPS WILL REMAIN FOR KODIAK INTO MIDWEEK AS
ONSHORE FLOW CONTINUES AND ANOTHER LOW DRAWS NEARER IN THE SOUTHERN
GULF.

LOOK FOR GUSTY NORTHERLY WINDS TO PICK UP TONIGHT AS WEAK COLD
ADVECTION COMBINES WITH A TIGHTENING GRADIENT/INCREASING UPPER LEVEL
SUPPORT. WINDS SHOULD CLIMB HIGH ENOUGH TO WARRANT STRONG WIND
HEADLINES THROUGH THE MATANUSKA VALLEY TONIGHT AND TUESDAY. LOOK FOR
THE GUSTY WINDS TO CONTINUE THROUGH THE USUAL GAPS THROUGH THE REST
OF THE WEEK AS THE GRADIENT SHOWS LITTLE SIGN OF LETTING UP.

.SOUTHWEST ALASKA...WINDS ACROSS BRISTOL BAY WILL BE ENHANCED BY THE
UPPER LEVEL TROUGH MOVING OVERHEAD TODAY RESULTING IN STRONGER GUSTS
THROUGH CHANNELED TERRAIN TODAY. OTHERWISE...EXPECT LITTLE IN THE WAY
OF CHANGE TO THE CURRENT WEATHER AS HIGH PRESSURE WILL REMAIN IN
CONTROL THROUGH THE REST OF THE WEEK.

.ALEUTIANS AND BERING SEA...THE PASSAGE OF THE UPPER LEVEL TROUGH
WILL BRING SCATTERED SHOWERS TO THE AKPEN THROUGH TUESDAY. SCATTERED
SHOWERS WILL ALSO BE FOUND ACROSS MUCH OF THE ALEUTIAN CHAIN TODAY AS
THE WEAKENING LOW SLIDES SOUTHEAST AWAY FROM THE ISLANDS AND THE OLD
FRONTAL BOUNDARY STRETCHES AND DISSIPATES. THE NEXT MAJOR FRONTAL
SYSTEM ARRIVES IN THE WESTERN ALEUTIANS TUESDAY AFTERNOON AND MOVES
TO THE CENTRAL ALEUTIANS BY WED MORNING BEFORE STALLING OUT OVER THE
EASTERN ALEUTIANS IN THE FACE OF THE BLOCKING RIDGE...MUCH AS THE
CURRENT FRONTAL BOUNDARY DID. THIS SYSTEM WILL ALSO GRADUALLY SHEAR
OUT ON THURSDAY AS THE ENERGY SPLITS AROUND THE RIDGE.

.LONG TERM FORECAST...LITTLE CHANGE OVER SOUTHCENTRAL AND SOUTHWEST
ALASKA THROUGH THE END OF THE WEEK AND NEXT WEEKEND AS HIGH PRESSURE
SHOWS NO SIGN OF ABATING. UNSETTLED WEATHER WILL BE CONFINED MAINLY
TO THE ALEUTIANS AND WESTERN BERING AS A SERIES OF LOWS TRANSITIONS
ALONG OR SOUTH OF THE ALEUTIANS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING...130 132 138 176
         HEAVY FREEZING SPRAY WARNING...185
FIRE WEATHER...NONE.

WOOD FEB 11