Snow Advisory 5, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AST THU JAN 24 2008

.MODEL DISCUSSION...MODELS IN GENERALLY GOOD AGREEMENT. GFS PREFERRED
FOR ITS CONSISTENCY AND LOW NOISE LEVEL. NAM HAVING DIFFICULTY
LOCKING ONTO THE TRIPLE POINT LOW THAT DEVELOPS IN THE EASTERN BERING
THIS MORNING.

.WESTERN DOMAIN...
LARGE 967 MB LOW CENTERED ABOUT 200 NM NORTH OF SHEMYA WILL MAINTAIN
INTENSITY AS IT MOVES SLOWLY NORTHEASTWARD TODAY. THE LOW RAPIDLY
WEAKENS BEGINNING THIS EVENING AND HEADS EASTWARD TO NEAR NUNIVAK
ISLAND FRIDAY MORNING WITH A CENTRAL PRESSURE OF ONLY 1000 MB. IT
THEN MOVES INLAND AND DISSIPATES BY FRI EVENING. STORM FORCE WINDS
TODAY AND TONIGHT ALONG THE SOUTHERN FLANK OF THE LOW.
THE ASSOCIATED COLD FRONT IS RAPIDLY OCCLUDING. AS OF 4AM IT EXTENDS
SOUTHWARD THROUGH THE CENTRAL ALEUTIANS. GFS PROGS THE FRONT TO PASS
OVER THE PRIBILOFS AND EASTERN ALEUTIANS BY THIS AFTERNOON. MOVE
THROUGH THE EASTERN BERING AND ALASKA PENINSULA THIS EVENING. THEN
MARKEDLY WEAKEN AS IT MOVES INLAND LATE TONIGHT.
PLENTY OF WARM AIR ADVECTION IN ADVANCE OF THIS SYSTEM. SIGNIFICANT
SNOWFALL POSSIBLE ACROSS THE SOUTHWESTERN MAINLAND. COMBO OF SNOW AND
WIND IS ALREADY CREATING BLIZ CONDITIONS ACROSS COASTAL SECTIONS OF
THE KUSKOKWIM DELTA. EAST WINDS WILL SHIFT TO THE SOUTH AND DIMINISH
TOWARD NOON. PRECIPITATION  FALLING MAINLY AS RAIN OVER THE EASTERN
ALEUTIANS AND ALASKA PENINSULA.
COLD AIR ADVECTION ON THE BACKSIDE WILL KEEP MOST OF THE BERING ZONES
SLATHERED IN SNOW SHOWERS THROUGH TODAY AND TONIGHT.
SMALL TRIPLE POINT LOW IS EXPECTED TO DEVELOP IN THE EASTERN BERING
THIS MORNING. MOVE INLAND THIS EVENING AND DISSIPATE OVER INTERIOR
ALASKA TONIGHT. EXACT TRACK OF THIS FEATURE COULD SIGNIFICANTLY
IMPACT FORECAST FOR KUSKOKWIM DELTA AND PORTIONS OF THE BRISTOL BAY
ZONE. DEVELOPMENT AND TRACK OF THIS FEATURE BEARS WATCHING.

.EASTERN DOMAIN...
SURFACE TROUGH OF LOW PRESSURE ALONG THE NORTHERN AND EASTERN GULF
COASTS SHOULD BREAK DOWN THIS MORNING. NORTHEAST GAP FLOW WILL
DIMINISH AROUND NOON. GOOD UPPER LEVEL SUPPORT FOR NORTH WINDS ALSO
DROPS OFF TODAY.
SNOWFALL WILL BE DEVELOPING FROM WEST BEGINNING LATE THIS AFTERNOON
AND SPREADING ACROSS THE WHOLE OF SOUTHCENTRAL BY MIDNIGHT AS A
RESULT OF THE APPROACHING BERING SEA FRONT.
COLD AIR ADVECTION IN THE LOWEST LEVELS COMBINED WITH WARM AIR
ADVECTION ALOFT IS A SOLID PRESCRIPTION FOR SIGNIFICANT SNOWFALL
AMOUNTS.
A 997 MB LOW IS PROGGED TO DEVELOP IN THE VICINITY OF THE BARREN
ISLANDS THURSDAY NIGHT AS THE UPPER LEVEL TROUGH CUTS SOUTHEASTWARD.
SNOW TAPERING OFF DURING THE DAY FRIDAY AS THE UPPER LEVEL FLOW
SHIFTS FROM SOUTHWEST TO NORTHWEST.

.BEYOND 36 HOURS...
NORTHWEST WINDS AND SNOW SHOWERS WILL LINGER OVER SOUTHCENTRAL INTO
FRIDAY NIGHT. THEN CLEAR AND COLD AND BREEZY.
ANOTHER BIG STORM POISED TO BE ABOUT 400 MILES WEST OF SHEMYA FRI
NIGHT AND IS EXPECTED TO FOLLOW A SIMILAR TRACK TO CURRENT BERING
LOW.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZ 155.
MARINE...GALE 120 132 150 155 160 165 170 172 175 176 179 180 185
         STORM 130
         HEAVY SPRAY 129 130 138 185
FIRE WEATHER...NONE.

ASB JAN 08