Blizzard Watch 30, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM AKST MON DEC 22 2008

.MODEL DISCUSSION...
THE MODELS THIS MORNING ARE IN GOOD AGREEMENT THROUGH WEDNESDAY. WE
START TO SEE DIFFERENCES IN THE HANDLING OF THE LOW MOVING ACROSS THE
WESTERN ALEUTIANS IN THE BERING SEA FOLLOWED BY MORE SIGNIFICANT
DIFFERENCES WITH REGARD TO THIS LOW AND HOW IT MOVES INTO BRISTOL BAY
AND THEN INTERACTS WITH THE LOW MOVING UP FROM THE NORTH PACIFIC
TOWARD THE ALASKA PENINSULA. WEDNESDAY NIGHT THE GFS ANS NAM ARE IN
AGREEMENT WITH THE STRENGTH AND POSITION OF THE LOW JUST SOUTH OF
UNALASKA WHILE THE UKMET AND ECMWF BOTH DIFFER FROM EACH OTHER AND
THE NAM AND GFS. THIS TENDS TO RESULT IN LOWER CONFIDENCE IN THE
FORECAST OVER THE EASTERN BERING AND AK PENINSULA AT THIS TIME AND
THEREFORE WE WILL NOT DEVIATE MUCH FROM THE CURRENT FORECAST PACKAGE
BEYOND TUESDAY NIGHT.

.ANALYSIS AND UPPER LEVELS...
THE UPPER LEVEL RIDGE OVER THE EASTERN PART OF THE STATE CONTINUES
TO GET PUSHED EAST AS THE UPPER LOW OVER THE NORTHERN BERING SEA
MOVES OVER THE SEWARD PENINSULA AND DIGS A TROUGH SOUTHEAST TO AN
UPPER LOW ALONG THE NORTH GULF COAST TUE NIGHT.

THE UPPER LEVEL JET IS RUNNING ALONG THE ALEUTIANS THEN DIVES
SOUTHEAST FROM THE WESTERN GULF OF ALASKA ALONG THE WEST COAST OF
NORTH AMERICA.

A WEAK LOW FORMING NEAR THE BARREN ISLANDS WILL DRIFT INTO PRINCE
WILLIAM SOUND A DISSIPATE TO A TROUGH TONIGHT. A SURFACE LOW RAPIDLY
MOVING ACROSS BRISTOL BAY TONIGHT MOVES TO NEAR MIDDLETON ISLAND TUE
MORNING AND DIVES SOUTHEAST TUESDAY NIGHT.

THE ZONAL FLOW FROM WEST TO EAST ACROSS THE BERING SEA WILL PERSIST
AT THE SURFACE AND ALOFT THROUGH WEDNESDAY. A NORTH PACIFIC LOW WILL
GET ENTRAINED IN THE ZONAL FLOW AND RAPIDLY MOVE ACROSS THE WESTERN
ALEUTIANS TUESDAY NIGHT THEN INTO BRISTOL BAY WEDNESDAY NIGHT BEFORE
CROSSING THE ALASKA PENINSULA AND MOVING INTO THE WESTERN GULF OF
ALASKA THURSDAY.

.SHORT TERM FORECAST...
SOUTH CENTRAL...
THE FOG OVER SOUTH CENTRAL ALASKA HAS LIFTED TO A STRATUS LAYER AND
IS LESS OF A PROBLEM THAN IT WAS OVERNIGHT AND EARLY THIS MORNING.
THE UPPER LEVEL TROUGH IS MOVING THROUGH THE COOK INLET AND SOUTH
CENTRAL REGION THIS AFTERNOON PRODUCING LIGHT SNOW OVER THE KENAI
PENINSULA AND IN THE SUSITNA VALLEY. THE SNOW IS EXPECTED TO BEGIN
LATE THIS AFTERNOON IN THE NORTHERN INLET. SNOW ACCUMULATIONS ARE
STILL EXPECTED TO BE FAIRLY LIGHT IN MOST AREAS. A SECOND STRONGER
WAVE WILL MOVE OVER SOUTH CENTRAL ALASKA AGAIN ON TUESDAY. THIS IS
EXPECTED TO BRING MORE SNOW THAN THE FIRST SHORT WAVE.

SOUTHWEST...
SNOW AND BLOWING SNOW HAS BEEN AN ISSUE OVER THE KUSKOKWIM DELTA
TODAY. MORE MOISTURE WILL MOVE INTO THE REGION TONIGHT AND IS
EXPECTED TO CONTINUE INTO TUESDAY.

ALEUTIANS/BERING...
WITH A ZONAL FLOW PERSISTING OVER MOST OF THE AREA EXPECT GUSTY SOUTH
TO SOUTHWESTERLY WINDS WILL CONTINUE FOR THE NEXT COUPLE DAYS WITH
SNOW OR RAIN AND SNOW SHOWERS CONTINUING THROUGH TUESDAY.

.LONG TERM FORECAST...
WE ARE STICKING WITH THE CURRENT FORECAST PACKAGE AND EXPECT THE LOW
IN THE NORTHERN GULF DRIFT OFF TO THE SOUTHEAST BEING REPLACED BY A
RIDGE OF HIGH PRESSURE WEDNESDAY.  OUT WEST HIGH PRESSURE WILL BUILD
INTO THE WESTERN ALEUTIANS AND BERING SEA THURSDAY NIGHT.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...STORMS 130 132 185 351 352.
         GALES 120 138 140 141 150 155 160 165 170 171 172 175 176
               179 180 411 412 413 414.
FIRE WEATHER...DONE.

SAM DEC 08