Small Craft Advisory 898, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 PM AKST THU DEC 8 2011

.ANALYSIS AND UPPER LEVELS...THE UPPER LEVEL PATTERN OVER THE STATE
REMAINS LARGELY UNCHANGED. THE LONG WAVE TROUGH OVER THE KAMCHATKA
PENINSULA REMAINS ENTRENCHED. THE UPPER LEVEL RIDGE AXIS HAS PUSHED A
LITTLE FARTHER EASTWARD FROM YESTERDAY LEAVING ZONAL UPPER LEVEL FLOW
OVER THE ALEUTIANS WHICH TURNS NORTHEAST OVER THE GULF OF ALASKA.
AT THE SURFACE THE LOW NEAR THE BERING STRAIT WILL CONTINUE TO MOVE
NORTHWARD AND WEAKEN AS THE NEXT LARGE LOW IS RAPIDLY STRENGTHENING
SOUTHWEST OF ATTU. A FRONT EXTENDING OUT OF THE BERING STRAIT FRONT
IS OVER THE KUSKOKWIM DELTA AND BRISTOL BAY REGION WHICH IS MOVING
EASTWARD INTO SOUTH CENTRAL ALASKA OVERNIGHT. FARTHER EAST THE FRONT
THAT WAS BRINGING PRECIPITATION INTO SOUTH CENTRAL ALASKA YESTERDAY
HAS MOVED NEAR THE ALCAN BORDER.

.MODEL DISCUSSION...MODELS ARE DOING WELL IN THE SHORT TERM. THEY
HAVE COALESCED INTO A REASONABLE COMMON SOLUTION WITH THE LARGE STORM
IN THE BERING SEA. WHAT WILL BE AN INTERESTING DEVELOPMENT TO WATCH
IS THE FORMATION OF A LOW THAT THE NAM GFS AND ECMWF HAVE IN THE
NORTHERN GULF ON SUNDAY. THESE MODELS EACH HAVE A LOW THERE BUT THE
GFS AND NAM DEVELOP IT ABOUT 200 MILES SOUTHWEST OF KODIAK ISLAND ON
SATURDAY WHILE THE ECMWF DEVELOPS THE MAIN LOW WELL SOUTHWEST OF THE
AREA AND THEN MOVES IT VERY QUICKLY INTO THE GULF. THE NAM/GFS
SOLUTION LOOKS LIKE THE MORE REASONABLE SOLUTION FOR THIS LOW.

.SHORT TERM FORECAST...THE FRONT IN THE BRISTOL BAY AND KUSKOKWIM
VALLEY IS BRINGING A RAIN SHOWERS AND SNOW SHOWERS TO THOSE AREAS. AS
THIS FRONT MOVES EASTWARD OVERNIGHT SNOW SHOWERS WILL MOVE THROUGH
THE SOUTH CENTRAL REGION AND DIMINISH IN SOUTHWEST ALASKA.

THE FRONT NEAR THE ALCAN BORDER BROUGHT A SNOW ADVISORY TO THE COPPER
RIVER BASIN TODAY. THE SNOW HAS LARGELY MOVED INTO THE EASTERN PART
OF THE BASIN THOUGH THERE WILL BE SOME FOG THAT DEVELOPS BEHIND IT.

THE STRONG LOW SOUTHWEST OF ATTU WILL MOVE INTO THE NORTHWESTERN
BERING SEA AND BRING GALES AND STORM FORCE WINDS TO THE ALEUTIANS AND
THE MAJORITY OF THE BERING SEA. MOST OF THE PRECIPITATION IN THE
ALEUTIANS WILL BE IN THE FORM OF RAIN WITH THIS SYSTEM UNTIL THE COLD
AIR WRAPS AROUND AND BRINGS IN SNOW SHOWERS IN NORTHWEST FLOW.

.LONG TERM FORECAST...THE LONG WAVE PATTERN DOES NOT CHANGE A LOT
THROUGH THE MIDDLE OF NEXT WEEK. THE DOMINANT UPPER LEVEL LOW WILL
REMAIN OVER THE WESTERN BERING SEA WITH A LARGE UPPER LEVEL RIDGE
OVER THE WEST COAST OF NORTH AMERICA. THERE WILL BE SOME WAVES THAT
MOVE THROUGH OVER THAT PERIOD BUT THE FLOW REMAINS STRONG
SOUTHWESTERLY OVERT HE STATE WHICH WILL KEEP THE AREA IN AN ACTIVE
STORM TRACK WITH MOSTLY ABOVE AVERAGE TEMPERATURES.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 130 150 155 160 165 170 172 179 180 185.
         STORM 175 176. HEAVY FREEZING SPRAY 185.
FIRE WEATHER...NONE.

DEC 11