Small Craft Advisory 353, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM ADT SUN APR 20 2008

.MODEL DISCUSSION...
MODELS CONTINUE TO BE IN VERY GOOD AGREEMENT OVER BOTH MAINLAND
ALASKA AND THE BERING SEA. THEY ARE ALL MOVING THE AREA OF HIGH
PRESSURE OVER THE GULF AND SOUTHERN ALASKA WEST TOWARD BRISTOL BAY
TUE NIGHT AND ARE MERGING THE BERING SEA LOW INTO THE LOW SOUTH OF
THE ALEUTIANS TONIGHT AND MOVING THE COMBINED SYSTEM EASTWARD.

.ANALYSIS AND UPPER LEVELS...
THE UPPER HIGH REMAINS NEARLY STATIONARY OVER THE NORTHERN GULF OF
ALASKA WITH AN UPPER LOW MOVING EAST OVER THE WESTERN ALEUTIANS. THE
300 MB JET STREAM LIES OVER SOUTHWEST ALASKA.

THE SURFACE PATTERN REFLECTS THE UPPER LEVEL SYSTEMS WITH A NEAR
STATIONARY LOW OVER THE GULF AND A LARGE LOW OVER THE BERING SEA. THE
STRONG PRESSURE GRADIENT OVER SOUTHWEST ALASKA AND EASTERN BERING SEA
HAD CREATED GUSTY SOUTHEAST WINDS ALONG THE IMMEDIATE COAST AND
THROUGH CHANNELED TERRAIN ALONG THE ALASKA PENINSULA AND EASTERN
ALEUTIANS. MOST OF THE PRECIPITATION IS ASSOCIATED WITH THE LOW
COMPLEX OVER THE BERING SEA BUT A FEW AREAS OF SHOWER HAVE DEVELOPED
ALONG THE PACIFIC SIDE OF THE ALASKA PENINSULA AND SOUTHERN KODIAK
ISLAND DUE TO OROGRAPHIC LIFT.

.SHORT TERM FORECAST...
THE AREA OF HIGH PRESSURE IN THE UPPER ATMOSPHERE OVER THE GULF OF
ALASKA AND THE CENTRAL MAINLAND WILL REMAIN STATIONARY THROUGH
TUESDAY THEN WILL BEGIN TO DRIFT WEST TOWARD BRISTOL BAY WEDNESDAY.
SKIES OVER SOUTHCENTRAL ALASKA WILL REMAIN MOSTLY CLEAR THROUGH
MIDWEEK.

OUT OVER THE BERING SEA...THE COMPLEX LOW OVER THE BERING WILL SHIFT
SOUTHWARD AS THE NORTHERN LOBE OVER THE CENTRAL BERING WEAKENS FASTER
THAN THE SOUTHERN LOBE SOUTH OF THE CENTRAL ALEUTIANS TONIGHT. THE
SOUTHERN LOW WILL BECOME EARLY STATIONARY OVER THE EASTERN ALEUTIANS
MONDAY NIGHT AND TUESDAY. AREAS OF RAIN AND SNOW SHOWERS OVER MOST OF
THE BERING WILL SHIFT SOUTHWARD WITH THE LOW PRESSURE.

.LONG TERM FORECAST...
THE UPPER HIGH SOUTH OF THE ALASKA PENINSULA WEDNESDAY WILL SLOWLY
DISSIPATE THURSDAY. THE RIDGE OVER THE GULF OF ALASKA AND MAINLAND
ALASKA WILL MOVE TOWARD THE ALCAN BORDER FRIDAY. THE UPPER LOW OVER
SIBERIA WEDNESDAY WILL MOVE TO NEAR WRANGEL ISLAND BY FRIDAY. AN
UPPER TROUGH WILL EXTEND SOUTHWARD OVER THE EASTERN BERING SEA
THURSDAY AND MOVE INTO WESTERN ALASKA FRIDAY. COOLER TEMPERATURES AND
SNOW WILL MOVE INTO WESTERN ALASKA THURSDAY. RAIN AND SNOW SHOWERS
WILL MOVE INTO THE SUSITNA VALLEY AND COOK INLET FRIDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 170, 175, 176
FIRE WEATHER...NONE.

NM APR 08