Gale Warning 1008, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 AM AST TUE DEC 12 2006

.DISCUSSION...

ANALYSIS..A WELL WRAPPED LOW NEAR SEWARD WILL MOVE INLAND OVER THE
KENAI PENINSULA TODAY. NAM INITIALIZED MOVEMENT WELL ON THIS SYSTEM.
A SECONDARY LOW ASSOCIATED WITH A TROUGH STRETCHING OUT FROM THE LOW
OVER THE PANHANDLE WILL DEVELOP THIS EVENING NEAR THE BARREN ISLANDS
AND MOVE NEAR MIDDLETON ISLAND AT 60 HRS. A TROUGH AXIS EXTENDS FROM
SOUTH OF KODIAK ISLAND TO THE BERING STRAIT. COLD NORTHERLY FLOW IS
PRESENT ACROSS THE BERING AND ALEUTIANS TO THE WEST OF THE TROUGH
AXIS. THE MEAN TROUGH AXIS WILL GENERALLY REMAIN IN PLACE THROUGH
THURSDAY. BEGINNING WEDNESDAY...A SHORTWAVE RIDGE WILL PROGRESS FROM
WEST TO EAST THROUGH THE BERING AND THEN ACROSS THE MAINLAND ON
FRIDAY. BEHIND THIS RIDGE WILL BE A RATHER LARGE AREA OF LOW PRESSURE
ACROSS THE BERING ON FRIDAY WHICH WILL ALSO TEND TO PROGRESS EAST
ACROSS THE REGION. HOWEVER MODELS ARE VERY INCONSISTENT WITH BOTH
STRENGTH AND TRACK OF THIS BERING LOW.

...FORECAST SOUTH AND EAST OF THE ALASKA RANGE...
CHALLENGING FORECAST FOR THIS REGION REGARDING THE EVOLUTION OF
NUMEROUS LOW PRESSURES OVER THE GULF OF ALASKA OVER THE NEXT FEW
DAYS. ANOTHER LOW CENTER IS LIKELY TO FORM NEAR
KODIAK TUESDAY NIGHT AS THE FIRST LOW WEAKENS OVER THE KENAI. THIS
SECOND LOW WILL ALSO TRACK TO NEAR MIDDLETON ISLAND...MEANING
CONTINUED SNOW FOR COASTAL AREAS INTO THURSDAY. THE MATANUSKA VALLEY
TO THE ANCHORAGE BOWL TO THE WESTERN KENAI HAS A DECENT SHOT OF
ACCUMULATING SNOW AT SOME POINT WEDNESDAY THROUGH THURSDAY WITH A
UPPER LEVEL TROUGH MOVING OVER THE AREA...BUT AT THIS POINT IT IS
VERY DIFFICULT TO DETERMINE EXACTLY WHEN THE BEST SHOT WILL BE. A
SHORTWAVE RIDGE MOVES INTO SOUTHCENTRAL FOR FRIDAY...WITH A RETURN TO
UNSETTLED WEATHER FOR AT LEAST COASTAL SOUTHCENTRAL FOR THE WEEKEND.

...SOUTHWEST MAINLAND FORECAST...
MAIN CHALLENGE IN THE SHORT TERM FOR THE SOUTHWEST MAINLAND INVOLVES
DETERMINING WHERE A BAND OF LIGHT SNOW SETS UP ALONG THE TROUGH
AXIS. THE BAND IS PRESENTLY LOCATED FROM DILLINGHAM TO BETHEL. MODELS
KEEP THIS BAND OF LIGHT SNOW CLOSE TO STATIONARY THROUGH
TUESDAY...THEN PUSH THE BAND EAST. NOT EXPECTING ANY  ADVISORY LEVEL
SNOW AMOUNTS FROM THIS BAND AT THE MOMENT. GENERALLY UNSTABLE WEST TO
NORTHWEST FLOW TO PERSIST OVER THE REGION THROUGH THURSDAY BEFORE A
SHORTWAVE RIDGE MOVES IN FROM THE WEST FOR FRIDAY.

...BERING SEA/ALEUTIANS FORECAST...
COLD NORTHWEST FLOW WITH ABUNDANT SNOW SHOWERS IS PRESENT ACROSS THE
BERING AND ALEUTIANS. THESE SNOW SHOWERS HAVE BEEN HEAVY ENOUGH TO
PRODUCE ACCUMULATING SNOW. THESE CONDITIONS WILL PERSIST INTO
WEDNESDAY...WHEN A SHORTWAVE RIDGE WILL BEGIN TO QUICKLY MOVE FROM
WEST TO EAST THROUGH THE AREA. BEHIND THIS SHORTWAVE RIDGE WILL BE A
RATHER LARGE LOW PRESSURE SYSTEM BEGINNING TO AFFECT THE WESTERN
ALEUTIANS ON THURSDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...HEAVY FREEZING SPRAY 160 185
         GALE WARNING 120 125 150

RNW DEC 06