Winter Weather Advisory 2, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
500 AM AKST THU JAN 13 2011

.MODEL DISCUSSION...
MODELS IN GOOD AGREEMENT THROUGH THE SHORT TERM. ECMWF MUCH MORE
AGGRESSIVE IN MOVING STORM IN SOUTH OF KODIAK AT 84 HOURS THAN GFS.
MORE CONSERVATIVE GFS SOLUTION PREFERRED THROUGH THE MIDTERM.
TRENDED TOWARDS HPC GUIDANCE IN THE LONG RANGE.

.ANALYSIS AND UPPER LEVELS...
DOMINANT UPPER LEVEL HIGH CENTERED OVER NORTHERN CHUKCHI SEA MOVES
OFF INTO WESTERN RUSSIA BY SUNDAY MORNING. TRANSVERSE LONG WAVE
TROUGH DEVELOPS ACROSS ALEUTIANS AND SOUTHWESTERN ALASKA BY SATURDAY
MORNING. AT THE SURFACE...MAIN STORM TRACK STAYS WELL SOUTH OF
ALEUTIAN CHAIN THROUGH THE WEEKEND. BROAD EASTERLY FLOW DEVELOP
ACROSS THE BERING SEA WHILE FLOW REMAINS OUT OF THE NORTH OVER
MAINLAND ALASKA.

.SHORT TERM FORECAST...
CONTRAST OF HIGH PRESSURE OVER NORTHERN ALASKA AND LOWER PRESSURE IN
THE GULF OF ALASKA IS GENERATING GUSTY NORTH WINDS THROUGH CHANNELED
AREAS LEE OF THE ALASKA AND CHUGACH RANGES. A MODERATE MID-LEVEL
SHORT WAVE WILL PASS OVER SOUTHCENTRAL ALASKA TODAY AND FURTHER
ENHANCE THESE WINDS. HURRICANE FORCE WIND GUSTS EXPECTED OUT OF THE
NORTHEAST LATER THIS MORNING IN THE MATANUSKA VALLEY. UPPER LEVEL
ENHANCEMENT COULD ALSO GENERATE DANGEROUSLY HIGH WINDS ALONG THE
KUSKOKWIM DELTA COAST LATE THIS AFTERNOON. GRADIENT BEGINS TO LOOSEN
SATURDAY MORNING AS HIGH PRESSURE BUILDS IN AT THE SURFACE OVER
SOUTHCENTRAL AND SOUTHWESTERN ALASKA.
STRATUS FOG AND LIGHT SNOW EXPECTED TO CONTINUE THROUGHOUT THE DAY
OVER THE CENTRAL AND EASTERN BERING SEA. INCREASING NORTHEAST WINDS
SHOULD PRODUCE ENOUGH MIXING TO ELIMINATE THE LOW CLOUDS AND FOG BY
LATE THIS EVENING BUT SCATTERED SNOW SHOWERS WILL CONTINUE THROUGH
THE WEEKEND.

.LONG TERM FORECAST...
STORM TRACK EDGES A BIT NORTHWARD BY THE END OF THE
WEEKEND...ALLOWING NORTH PACIFIC STORMS TO JUST GRAZE THE ALEUTIANS
AND KODIAK ISLAND. WEAK HIGH PRESSURE BUILDS IN AT THE SURFACE OVER
INTERIOR SOUTHCENTRAL AND SOUTHWESTERN ALASKA AND A SUBSIDENCE
INVERSION WILL BEGIN TO DEVELOP...USHERING IN A RETURN TO NEAR ZERO
TEMPERATURES FOR MOST INLAND AREAS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING ZONE 111. HIGH WIND WATCH ZONE 155.
MARINE...GALE 130 138 140 172 175 176 185 352 412
         HEAVY SPRAY 121 138 140 179 185 414
FIRE WEATHER...NONE.

ASB JAN 11