Small Craft Advisory 1074, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM AST THU DEC 22 2005

.DISCUSSION...
WEAK LOW OVER SOUTH CENTRAL ALASKA LIFTING NORTH AS ANOTHER LOW
PRESSURE SYSTEM WORKS AROUND THE GULF OF ALASKA. ENOUGH WARM AIR AT
MID LEVELS TO PRODUCE AREAS OF FREEZING RAIN LAST NIGHT THROUGH THIS
MORNING. PRECIP WANING THIS AFTERNOON AS THE LOW WEAKENS. MODELS NOT
PICKING UP ON CLOSED CIRCULATION PER IR IMAGERY IN THE GULF OF ALASKA
WEST OF 144W. SEEMS TO BE AN UPPER LEVEL VORTICITY MAX AS BUOY AND
SHIP OBSERVATIONS ARE NOT REFLECTING THIS FEATURE. EITHER WAY...IT
WILL BRING MORE CLOUDS AND PRECIPITATION TO THE WESTERN GULF THAN
PREVIOUSLY ANTICIPATED. SURFACE LOWS HOWEVER ARE INITIALIZED RATHER
WELL. HOWEVER...THE DEPTH OF THE LOWS IS MORE IN LINE WITH THE GFS
RIGHT NOW.

UPPER LEVELS...LOW AMPLITUDE RIDGE OVER THE WESTERN CONUS MORE HIGH
AMPLITUDE OVER THE CANADIAN ROCKIES INTO THE EASTERN ALASKA. THIS IS
ALLOWING THE RESULTANT STORM TRACK TO BRING WARMER AIR TO SOUTH
CENTRAL ALASKA. PATTERN NOT TO CHANGE MUCH OVER THE NEXT WEEK.

THE CURRENT ANCHOR LOW SOUTH OF THE ALEUTIAN CHAIN WILL
WEAKEN...SPLIT AND LIFT NORTH ACROSS THE MAINLAND FRIDAY THROUGH
SATURDAY WITH A PORTION MOVING EAST TO THE PANHANDLE SATURDAY. THIS
IS DUE TO A RATHER STRONG LOW MOVING INTO THE WESTERN ALEUTIAN CHAIN
TONIGHT. THE LOW IS ACCOMPANIED BY A STRONG JET (200 KT) ORIGINATING
OFF THE COAST OF JAPAN. THIS JET PUSHES ALL THE WAY TO 160W ALONG 40N
BY SATURDAY NIGHT. THE LOW IN RESPONSE WILL WORK TO THE CENTRAL
ALEUTIAN CHAIN SATURDAY NIGHT. THE LOW EVENTUALLY MOVES INTO THE
WESTERN GULF EARLY NEXT WEEK AS ANOTHER LOW MOVES TO THE WESTERN
ALEUTIAN CHAIN.

SURFACE...WEAK LOWS FROM THE GULF TO THE PANHANDLE MOVING NORTHWEST
THROUGH THE GULF DOWNSTREAM OF UPPER LEVEL AND ASSOCIATED SURFACE LOW
OVER THE EASTERN ALEUTIAN CHAIN AND UPSTREAM OF RIDGE OVER THE
CANADIAN ROCKIES. THE AIR MASS IS SOMEWHAT UNSTABLE IN THIS REGION
WITH PLENTY OF PRECIPITATION WITH EACH SYSTEM. THE AIR MASS IS ALSO
SOMEWHAT WARM. IN FACT...WARM ENOUGH TO REMAIN A MIX OF PRECIPITATION
INTO THE SUSITNA VALLEY. IT WILL GET A BIT COLDER AS A PIECE OF THE
UPPER LEVEL LOW MOVES OVER SOUTH CENTRAL TOMORROW. UNTIL
THEN...EXPECT A MIX OF PRECIP OVER SOUTH CENTRAL WITH THE NEXT SYSTEM
MOVING TO THE PRINCE WILLIAM SOUND TONIGHT. THIS SYSTEM WILL LIFT
NORTH WITH A PIECE OF THE UPPER LEVEL LOW TOMORROW EVENING.

LOW LIFTING NORTH THIS AFTERNOON AND EVENING OVER SOUTH CENTRAL LEFT
PLENTY OF PRECIPITATION OVER THE AREA. WITH DECREASING
CLOUDS...EXPECT AREAS OF FOG TO DEVELOP OVER THESE INLAND AREAS
TONIGHT.

A STRONG 940 MB LOW TO MOVE TO THE WESTERN ALEUTIAN CHAIN TONIGHT AND
SLOWLY WEAKEN AS IT MOVES EAST THROUGH SATURDAY. STORM FORCE WINDS
WITH LARGE WAVE HEIGHTS TO ACCOMPANY THIS LOW ON ITS PATH INTO
TOMORROW. OVER SOUTHWEST ALASKA...TEMPS TO REMAIN CONSISTENT THROUGH
TOMORROW BUT WARM UP AT THE LOW LEVELS AS THE STRONG LOW MOVES ACROSS
THE ALEUTIAN CHAIN. THE TEMPS WILL COOL DOWN SIGNIFICANTLY BEHIND IT
AND WARM UP OVER SOUTH CENTRAL ALASKA EARLY NEXT WEEK AS THE LOW
MOVES INTO THE WESTERN GULF. IN ADDITION...GALE FORCE WINDS AND LARGE
WAVE HEIGHTS TO ACCOMPANY THE LOW AS IT WEAKENS AND MOVES TOWARD THE
GULF.

MOST PRECIPITATION WEST OF THE ALASKA RANGE DURING THIS TIME WILL BE
ASSOCIATED WITH THE LOW AND ITS FRONT. A STRONG FRONT AHEAD OF THE
LOW TO PUSH NORTH THROUGH THE GULF OF ALASKA SATURDAY NIGHT AND
SUNDAY BRINGING STRONG WINDS AND MODERATE TO HEAVY RAINFALL TO THE
GULF COASTAL LOCATIONS WITH ISOLATED TO SCATTERED SHOWERS MAKING
THEIR WAY INLAND OVER SOUTHWEST AND SOUTH CENTRAL ALASKA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...HEAVY FREEZING SPRAY 185
         STORM 175 176
         GALE 172
FIRE WEATHER...NONE

JN DEC 05