Blizzard in Alaska, March 13, 2008

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
130 PM ADT THU MAR 13 2008

.MODEL DISCUSSION...GFS/ECMWF MODELS INITIALIZED WELL AND FORECASTS
ARE REASONABLE AND SIMILAR THROUGH SUN NIGHT. DIFFERENCES CREEP IN
BEYOND THIS POINT...BUT 12Z GFS IS FAIRLY CLOSE TO 00Z RUN. SO ALL
SAID...WILL BLEND CURRENT GRIDS WITH 12Z GFS. THE FINAL RESULT BEING
VERY LITTLE CHANGE IN THIS AFTERNOONS FORECAST PACKAGE.

.UPPER LEVELS...TROUGH OVER THE CENTRAL MAINLAND THIS MORNING MOVES
INTO CANADA FRI. A HIGH PRESSURE RIDGE BUILDS OVER THE EASTERN BERING
SEA/WESTERN ALASKA TONIGHT AND MOVES OVER THE GULF AND CENTRAL
MAINLAND FRI NIGHT. THE RIDGE CONTINUES EASTWARD PROGRESS THROUGH THE
WEEKEND AS THE PRIMARY LOW CENTER SOUTH OF THE ALEUTIANS DEVELOPS AND
MOVES TO THE EASTERN ALEUTIANS SAT. STRONG SW JET SETS UP OVER THE
NORTH PACIFIC WELL SOUTH OF THE AK PEN AND PUSHES INTO THE GULF OF
ALASKA SAT AS THIS LOW CENTER PROGRESSES EAST SAT. SW JET AXIS PUSHES
SOUTH AND EAST SUN/MON AS LOW CENTER NEAR THE EASTERN ALEUTIANS SAT
MOVES TO THE NORTHERN GULF OF ALASKA MON AND WEAKENS. HIGH PRESSURE
REBUILDS BETWEEN 170E-180W BY MON NIGHT AND EXTENDS FROM THE NORTH
PACIFIC TO OVER THE BERING SEA.

.SHORT TERM FORECAST...
.EAST...OFF SHORE FLOW WITH DRYING IS FINALLY SETTING UP OVER
SOUTHCENTRAL ALASKA. THIS HAS BROUGHT LONG AWAITED CLEARING SKIES.
PRESSURE GRADIENTS WILL INCREASE OVER SOUTHCENTRAL AND NORTH GULF
TONIGHT WITH TROUGH OVER THE GULF. THAT COMBINED WITH WEAK COLD
ADVECTION WILL PRODUCE GUSTY GAP/DRAINAGE WINDS OVER MUCH OF THE GULF
AND PORTIONS OF SOUTHCENTRAL THROUGH FRI MORNING. HIGH PRESSURE INTO
THE REGION IN ADVANCE OF APPROACHING FRONTAL SYSTEM FRI AFTERNOON.
EXPECT INCREASING CLOUDS OVER THE WESTERN GULF FRI AFTERNOON WITH
RAIN AND SNOW TO THE WESTERN GULF FRI NIGHT. A TRIPLE POINT WILL
LIKELY FORM NEAR KODIAK SAT MORNING. STRONG SW FLOW SETTING UP ALOFT
LIKELY TO CARRY THIS CENTER TO THE EASTERN GULF SUN MORNING. PRESSURE
GRADIENT LIKELY TO BUILD OVER SOUTHCENTRAL WITH APPROACH OF FRONTAL
TROUGH SAT...SO SHOULD SEE STRONG GAP WINDS...ESPECIALLY ALONG
TURNAGAIN ARM AND PORTAGE VALLEY.

.WEST...
MAIN LOW CENTER SOUTH OF THE ALEUTIANS MOVES TO THE CENTRAL ALEUTIANS
FRI NIGHT. CENTER BECOMES STACKED WITH UPPER CENTER AND WEAKENS AS IT
EVENTUALLY ENDS UP IN THE GULF OF ALASKA MON. ASSOCIATED WEATHER
FRONT MOVES TO THE PRIBILOFS AND WESTERN AK PEN FRI AFTERNOON. FRONT
CONTINUES EAST PROGRESSION TO ALONG THE SW COAST AND KODIAK ISLAND
EARLY SAT. FRONT WEAKENS AS IT MOVES INTO THE INTERIOR SAT. BLIZZARD
CONDITIONS OVER THE PRIBILOFS STILL LOOK REASONABLE FOR BY 6PM
TODAY...IF NOT A LITTLE EARLIER. WILL LET BLIZZARD RUN INTO FRI...BUT
WILL HAVE TO REEVALUATE AS TEMPS MAY GET A LITTLE TOO WARM. BLIZZARD
WATCH FOR THE WESTERN ALEUTIANS LATE TONIGHT WILL BE A CLOSE CALL.
TEMPS CURRENTLY OVER THE WESTERN ALEUTIANS ARE ABOVE FREEZING. MODELS
STILL SHOWING WEAK COLD ADVECTION OVER THE WESTERN ALEUTIANS THROUGH
TONIGHT. NEXT CONCERN AREA WOULD BE BLOWING SNOW CONDITIONS ALONG THE
NORTH COAST OF BRISTOL BAY AND COASTAL SW AK WITH APPROACH FRONTAL
FRONT FRI NIGHT. STRATUS OVER SW ALASKA WILL HOLD THROUGH TONIGHT AND
START TO BREAK UP FRI WITH MIXING AHEAD OF BERING SEA FRONT.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 195. BLIZZARD WATCH 191
MARINE...STORM 176. GALES: 132 150 155 165 170 171 172 179 AND 185
FIRE WEATHER...NONE.

RMC MAR 08