Small Craft Advisory 1018, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
300 PM AKST FRI DEC 19 2008

.ANALYSIS AND UPPER LEVELS...THE MEAN LONG WAVE RIDGE REMAINS OVER
THE STATE. THE CHINK IN THIS BLOCKING RIDGE IS AN UPPER LEVEL LOW
OVER THE ALASKA PENINSULA. HOWEVER THIS RIDGE IS PULLING TO THE
SOUTHEAST AND WEAKENING WHICH WILL ALLOW THE THE UPPER RIDGE TO
STRENGTHEN A LITTLE MORE. THE SURFACE LOW IS A LITTLE SOUTHWEST OF
THE ALASKA PENINSULA AND WILL FOLLOW THE UPPER LOW INTO THE GULF.
A WEAK TRIPLE POINT LOW IS DEVELOPING SOUTH OF KODIAK ISLAND AND WILL
ROTATE NORTH OF THE MAIN LOW AS THE MAIN LOW MOVES SOUTHEAST.
A COMPLEX LOW IN THE FAR WESTERN BERING SEA WILL REMAIN IN PLACE
THROUGH THE WEEKEND.
THE MAIN JET STREAM IS SOUTH OF THE AREA AND WILL REMAIN SOUTH OF THE
AREA IN THE EASTERN PART OF THE FORECAST AREA. IN THE WEST THE JET
STREAM WILL MOVE OVER THE ALEUTIAN ISLANDS AND BERING SEA EARLY NEXT
WEEK.

.MODEL DISCUSSION...THERE IS A LITTLE BIT OF A DIFFERENCE IN THE
MODEL SOLUTIONS WITH THE WEAK TRIPLE POINT LOW SOUTH OF KODIAK
ISLAND. THE NAM KEEPS IT A LITTLE STRONGER AND BETTER ORGANIZED AS IT
ROTATES AROUND THE MAIN LOW. THE GFS IS THE WEAKEST WITH THIS SYSTEM
WITH IT BEING NOT MUCH MORE THAN A TROUGH.
OTHER THAN THAT THE MODELS LOOK PRETTY GOOD INTO MONDAY NIGHT.

.SHORT TERM FORECAST...PRECIPITATION IS MAINLY LIMITED TO A SWATH
FROM KODIAK THROUGH BRISTOL BAY AND AGAIN IN THE WESTERN ALEUTIANS.
THERE ARE ALSO SOME LINGERING RAIN AND SNOW SHOWERS ALONG THE ALASKA
PENINSULA THAT WILL BE DIMINISHING AS THE EVENING GOES ON.

.LONG TERM FORECAST...
SOMEWHAT OF A PATTERN CHANGE IN THE EXTENDED WITH FASTER PROGRESSIVE
FLOW OVER THE REGION AS A STRONG UPPER LEVEL ZONAL JET STREAM GETS
INVOLVED. THIS MEANS ACTIVE AND MORE CHANGEABLE WEATHER FOR THE
BERING/ALEUTIANS AND TRANSLATING EAST TOWARD THE MIDDLE OF THE WEEK.
IT IS STILL HARD TO TELL JUST HOW MUCH OF A CHANGE THE MAINLAND WILL
SEE HOWEVER.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 120 130 138 140 172 175 176.
FIRE WEATHER...NONE.

DEC 08