Small Craft Advisory 1003, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM AST WED NOV 30 2005

.DISCUSSION...
A MAJOR UPPER LEVEL RIDGE RESIDES FROM THE NORTH PACIFIC ACROSS THE
BERING SEA INTO THE RUSSIAN FAR EAST. A MAJOR UPPER LEVEL TROUGH OVER
THE ALASKA MAINLAND IS ANCHORED BY THE UPPER LOW OVER THE CANADIAN
ARCTIC. WE EXPECT THE UPPER TROUGH TO DIG INTO SOUTHWEST ALASKA AS A
UPPER LOW FORMS OVER THE BRISTOL BAY REGION THU NIGHT. THIS WILL
ERODE AT THE UPPER RIDGE OF HIGH PRESSURE ACROSS THE EASTERN BERING
SEA. AT THE SURFACE WE HAVE A RIDGE OF HIGH PRESSURE EXTENDING FROM
THE HIGH SOUTH OF THE ALASKA PENINSULA INTO THE RUSSIAN FAR EAST WITH
A WEAKER RIDGE EXTENDING FROM THE RUSSIAN FAR EAST ACROSS NORTHERN
ALASKA. LOW LEVEL COLD AIR REMAINS ENTRENCHED IN THE EASTERN INTERIOR
WHILE A LOW LEVEL COLD POCKET MOVES SOUTH FROM THE BERING STRAIT
ALONG THE BERING SEA COAST AND STALLING OVER BRISTOL BAY COINCIDENT
TO THE UPPER LOW PARKING OVER THAT REGION.

IN THE EAST...AREAS OF LOW CLOUDS WITH LOCALIZED PATCHY DENSE FOG
WILL PERSIST OVER THE SOUTH CENTRAL REGION AND THE COPPER RIVER BASIN
AND SUSITNA VALLEY AT LEAST THROUGH TONIGHT. WE MAY SEE BREAKS IN THE
LOWER CLOUDS AND FOG AS SOME MID LEVEL CLOUDS MOVER OVER THE REGION
FROM THE NORTH AND WEST TONIGHT AND FRIDAY. THE INVERTED TROUGH FROM
THE LOW OFF QUEEN CHARLOTTE ISLAND TO THE LOW SOUTHWEST OF YAKUTAT
INTENSIFIES TONIGHT AND FRIDAY. THE MAIN CONCERN WITH THIS IS
INCREASED NORTH WIND ALONG THE COASTAL MOUNTAINS OF PRINCE WILLIAM
SOUND AND THE NORTH GULF COAST THROUGH FRIDAY. THE INCREASE IN THE
INVERSION LAYER HEIGHT HAS ALLOWED MORE MIXING NEAR THE GROUND TO
OCCUR. THE INVERSION LAYER WILL CONTINUE TO WEAKEN AND THUS THE FOG
WILL NOT BE AS SIGNIFICANT A PROBLEM. ISOLATED SNOW SHOWERS WILL
PERSIST ALONG THE NORTH GULF COAST AS THE LOW REMAINS OVER THAT
REGION. ALSO EXPECT THE MODERATE NORTHWEST WIND TO PERSIST ACROSS
KODIAK ISLAND.

OUT WEST...MOISTURE FROM THE FRONT SOUTH OF THE WESTERN ALEUTIANS IS
TRANSITING ACROSS THE THE RIDGE OVER THE EASTERN GULF. NORTHWEST FLOW
OFF THE BERING SEA INTO THE KUSKOKWIM DELTA IS RESULTING IS LIGHT
SNOW ACROSS THE REGION, BUT MAINLY ALONG THE NORTH SIDE OF THE
KILBUCK MOUNTAINS. ISOLATED AREAS OF LIGHT SNOW ARE ALSO OCCURRING
INTO THE BRISTOL BAY REGION. THE MAIN IMPACT OF THIS CLOUD COVER IS
INCREASED TEMPERATURES AS THE RADIATION COOLING HAS BEEN MITIGATED BY
THE CLOUD COVER.

THE FRONT SOUTH OF THE WESTERN ALEUTIANS REMAINS NEARLY STATIONARY.
THIS WILL HOLD THE GRADIENT OVER THE BERING SEA AND ALEUTIANS BETWEEN
THE HIGH AND LOW AND EXPECT THE EAST WIND TO PERSIST FOR SEVERAL DAYS
WITH INCREASING WIND TONIGHT AND THURSDAY OVER THE WESTERN ALEUTIANS
AND WESTERN BERING SEA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...STORM 176 410
         GALE 130 132 175
         HEAVY FREEZING SPRAY 121 129 130
FIRE WEATHER...DONE

SAM NOV 05