Gale Warning 805, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM AKST FRI NOV 20 2009

.MODEL DISCUSSION...MODEL INITIALIZATIONS AND FORECAST TRENDS THROUGH

SAT NIGHT ARE IN GOOD AGREEMENT. PROBLEMS ARISE AFTER THIS AS THE NAM
BECOMES THE OUTLIER WITH THE NEXT STORM TO ENTER THE GULF OF ALASKA.
THE GFS MODEL IS CONVERGING TOWARD THE 00Z ECMWF SOLUTION BY BRINGING
A STRONG LOW CENTER INTO THE GULF OF ALASKA SUN NIGHT.  BY MON
AFTERNOON THE 12Z ECMWF CARRIES THE CENTER INTO THE INTERIOR...WHICH
IS A DEPARTURE FROM THE OOZ RUN WHICH HOLDS THE CENTER IN THE WESTERN
GULF. THE 12Z GFS TENDED TOWARD THIS POSITION...SO WILL CONTINUE WITH
THAT TREND OF THE 00Z ECMWF AND 12Z GFS. CONFIDENCE IS FAIRLY LOW IN
THE LONG TERM AS MODELS VARY CONSIDERABLY.

UPPER LEVELS...
THE PATTERN BECOMES SOMEWHAT MORE AMPLIFIED IN THE NE PACIFIC AND
ALASKA OVER THE NEXT COUPLE OF DAYS. THE LONG WAVE ALONG THE WESTERN
US MOVES EAST AS RIDGE BUILD OVER THE EASTERN GULF AND CENTRAL
MAINLAND SUN EVE. THE LOW OVER THE MAINLAND RETROGRADES TO SOUTH OF
THE GULF OF ANADYR SUN NIGHT. STACKED CENTER OVER THE WESTERN BERING
SEA WEAKENS AS DEVELOPING WAVE SOUTH OF THE WESTERN ALEUTIANS MOVES
TO OVER WESTERN BRISTOL BAY SAT NIGHT/SUN SETTING UP SWLY FLOW OVER
THE MAINLAND. YET ANOTHER WAVE DEVELOPS OVER THE NE PACIFIC SUN AND
MOVES TO THE NORTHERN GULF OF ALASKA MON.

.SHORT TERM FORECAST...

.EAST...TRIPLE POINT CENTER SOUTH OF KODIAK THIS MORNING WILL
CONTINUE EAST MOVEMENT AND WEAKEN. WEAK LOW WHICH IS FORMING SOUTH OF
THE KENAI PEN IS PRODUCING SNOW OVER THE GULF COAST AND HAS ENHANCED
THE WINDS OVER THE PRINCE WILLIAM SOUND AND NORTH GULF. SNOW SHOULD
BE TAPERING OFF AT KODIAK THROUGH THE NIGHT AS TIPPLE POINT MOVES
EAST. SNOW LIKELY TO CONTINUE ALONG THE NORTH GULF TONIGHT WITH WEAK
LOW HOLDING OVER THE NORTHERN GULF. SOME LIGHT OVERRUNNING SNOW WILL
WORK INLAND IN SOUTHCENTRAL TONIGHT WITH WEAK MOISTURE PUSH FROM THE
GULF. SNOW SHOULD TAPER OFF OVER SOUTHCENTRAL SAT NIGHT...BUT NEXT
SURGE COMES IN EARLY SUN AS FRONTAL TROUGH MOVES TO THE WESTERN GULF.
EASTERLY FLOW WILL INCREASE OVER THE GULF SUN NIGHT/MON AS A STRONG
LOW MOVES INTO THE GULF OF ALASKA. MAJORITY  PRECIPITATION WITH THIS
SYSTEM WILL LIKELY REMAIN INITIALLY ALONG THE COAST WITH DOWN-SLOPE
CONDITIONS INLAND. WARMER AIR WILL BRING MIXED PRECIPITATION WITH
THIS SYSTEM.

.WEST...A WEAKENING FRONTAL TROUGH OVER BRISTOL BAY IS PRODUCING SOME
LIGHT SNOW OVER THE AREA. SNOW WILL DIMINISH TONIGHT AS FRONT
CONTINUES TO WEAKEN AND MID LEVEL FLOW SHIFTS NORTH. STORM FORCE
WINDS SHOULD SLOWLY DIMINISH OVER THE WESTERN ALEUTIANS AS STACKED
STORM FORCE LOW IN THE WESTERN BERING SEA WEAKENS AND DRIFTS SOUTH.
SATELLITE IMAGERY SHOWS DEVELOPING WAVE MOVING RAPIDLY EAST TOWARD
THE WESTERN ALEUTIANS. MODELS PICK UP ON THIS CENTER AS IT
INTENSIFIES AND MOVES TO WESTERN BRISTOL BAY SUN NIGHT. THIS CENTER
THEN BECOMES STATIONARY AND WEAKENS THROUGH MON. ASSOCIATED FRONT
BRINGS SNOW AND BLOWING SNOW TO THE SW ALASKA COAST...ESPECIALLY
BRISTOL BAY SAT NIGHT.

.LONG TERM FORECAST...MODEL DIFFERENCES AND PROGRESSIVE PATTERN WILL
CAUSE TIMING ISSUES. HOWEVER...PATTERN IS SUCH THAT INCREASED CLOUDS
AND POPS WITH SOME WARMING ARE LIKELY THROUGH THE MIDDLE OF NEXT
WEAK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALES 155,180,170,171,172,175,176, AND 185.
FIRE WEATHER...NONE.

RMC NOV 09