Small Craft Advisory 1083, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
623 AM AST SAT DEC 22 2007

.ANALYSIS AND UPPER LEVELS...
COLD CORE UPPER LOW HAS COMPLETED ITS WESTWARD JOURNEY TO THE
NORTHERN BERING SEA WHERE IT WILL REMAIN THROUGH MID WEEK. COLDEST
AIR ASSOCIATED WITH THIS FEATURE HAS ALSO SHIFTED TO THE WESTERN
BERING AND INTO SIBERIA WHILE CENTRAL ALASKA RETURNS TO MORE
CLIMATOLOGICALLY NORMAL TEMPERATURES. MAIN SURFACE FEATURE IS A 974
MB LOW IN BRISTOL BAY BRINGING MOST OF SOUTHWEST AND SOUTHCENTRAL
SCATTERED SNOW SHOWERS. COLD AIR ADVECTING SOUTHWARD TO THE WEST OF
THIS LOW IS BRINGING A STEADY STREAM OF SNOW SHOWERS TO THE ALEUTIAN
CHAIN.

.MODEL DISCUSSION...
MODELS ARE IN MUCH BETTER AGREEMENT. CONSISTENCY BETWEEN RUNS HAS
ALSO INCREASED ALLOWING FOR MINIMAL CHANGES TO THIS FORECAST PACKAGE.
BASED THE MAIN SYNOPTIC FEATURES OFF OF THE 12Z GFS.

.SHORT TERM FORECAST...
SOUTHCENTRAL...
UPPER TROUGH TO THE WEST OF THE ALASKA RANGE IS PLACING SOUTHCENTRAL
IN SOUTHERLY FLOW ALOFT WHICH IS FAVORABLE FOR SCATTERED SNOW SHOWERS
AREA WIDE. WEAK SHORTWAVES WILL HELP INITIATE SHOWER ACTIVITY AS SEEN
ON THE KENAI AND MIDDLETON RADARS THIS MORNING. THE BEST CHANCE FOR
SNOW FOR SOUTHCENTRAL LOOKS TO BE SUNDAY WITH A VICIOUS SHORT WAVE
MOVING UP THE WESTERN GULF AND INLAND SUNDAY EVENING. AT THIS POINT
NOT LOOKING AT SIGNIFICANT SNOW FALL ALTHOUGH WESTERLY WINDS INTO
KACHEMAK BAY COULD BRIEFLY BRING BLIZZARD CONDITIONS TO HOMER AND THE
BLUFF...SOMETHING THAT WILL HAVE TO BE MONITORED WITH SUBSEQUENT
MODEL RUNS.

WEST OF THE ALASKA RANGE...
SNOW SHOWERS WILL DOMINATE THE WESTERN ZONES THROUGH THE WEEKEND. THE
NEXT NPAC LOW MOVES SOUTH OF THE CENTRAL ALEUTIANS TOMORROW AFTERNOON
AND LIKEWISE...WILL HAVE TO WATCH CLOSELY TO SEE HOW FAR NORTH THE
LOW MAKES IT. THIS WILL HAVE SIGNIFICANT IMPACT ON THE EASTERN
ALEUTIANS AND THE ALASKA PENINSULA SUNDAY NIGHT. ENOUGH WARM AIR
WOULD MAKE IT NORTH INTO THE ALASKA PENINSULA TO MIX THE PRECIP AND
AVOID BLIZZARD CONDITIONS ALTHOUGH DUTCH HARBOR HAS THE POTENTIAL TO
REMAIN ON THE COLD AIR SIDE AND UNDER THE TROWAL...ESSENTIALLY SEEING
THE HEAVIEST PRECIPITATION IN COMBINATION WITH THE COLDEST AIR. MAY
HAVE TO BUMP UP THE WORDING IN THAT ZONE SOONER THAN LATER IF THE
MODELS CONTINUE TO ADVERTISE THIS SCENARIO.

EXTENDED...CHRISTMAS FORECAST...STILL MUCH UNCERTAINTY AS WE GET INTO
EARLY NEXT WEEK ALTHOUGH THE GFS IS CURRENTLY SHOWING SOME FEATURES
THAT ALLOW AT LEAST THE POSSIBILITY OF A WHITE CHRISTMAS HERE IN
ANCHORAGE. HAVE WORDED THE FORECAST TO ACCOUNT FOR THAT POSSIBILITY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 195
MARINE...GALE WARNING ZONES 130 132 138 140 150 155 160 170 179.
         HEAVY FREEZING SPRAY WARNING ZONES 130 140 141 150 160 180
          185.
FIRE WEATHER...NONE.

AB DEC 07