Gale Warning 529, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM AKDT MON AUG 24 2009

.ANALYSIS AND UPPER LEVELS...
.UPPER LEVEL...THE UPPER TROUGH REMAINS OVER WESTERN ALASKA AND HAS
EXTENDED SOUTHEASTWARD TO LINK UP WITH AN UPPER LOW OVER THE
SOUTHEASTERN GULF. A BROAD UPPER RIDGE HAS MOVES INTO THE WESTERN
BERING SEA AND CONTINUES TO DRIFT EAST.

.AT THE SURFACE...THE MODERATE LOW JUST SOUTH OF THE EASTERN GULF IS
VERTICALLY STACKED UNDER THE UPPER LOW AND IS SLOWLY MOVING NORTH. A
WEAK WEATHER FRONT MOVING THROUGH THE COPPER RIVER BASIN AND PRINCE
WILLIAM SOUND HAS PRODUCED RAIN OVER THESE AREAS. ANOTHER MODERATE
LOW NEAR DUTCH HARBOR WILL CONTINUE TO MOVE SOUTHEAST INTO THE NORTH
PACIFIC TONIGHT. A RIDGE OVER THE WESTERN BERING IS LINKED TO THE
UPPER RIDGE IN ABOUT THE SAME POSITION AND WILL CONTINUE TO MOVE
WEST.

.MODEL DISCUSSION...
THE MODELS ARE IN VERY GOOD AGREEMENT AND HAD COME TO A BETTER
CONSENSUS ON FORMER TYPHOON VAMCO, THOUGH GFS AND NAM STRENGTHENS THE
STORM MORE THAN THE EUROPEAN MODEL AS IT MOVES ACROSS THE BERING
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT.

.SHORT TERM FORECAST...
.UPPER LEVELS...THE UPPER TROUGH WILL REMAIN OVER WESTERN ALASKA
THROUGH WEDNESDAY. AN UPPER SHORT WAVE ALONG THE WEST SIDE OF THE
TROUGH WILL MOVE THROUGH SOUTHWEST ALASKA THROUGH TUESDAY AND INTO
THE SUSITNA VALLEY AND COOK INLET WEDNESDAY. THE UPPER LOW MOVING UP
THE EASTERN GULF TONIGHT WILL DISSIPATE OVER NORTHEASTERN GULF
TUESDAY EVENING. THE UPPER RIDGE OVER THE WESTERN BERING WILL MOVE
EAST INTO SOUTHWEST ALASKA WEDNESDAY.

.SOUTH CENTRAL ALASKA AND THE GULF...THE WEAKENING FRONT OVER THE
COPPER RIVER BASIN WILL DISSIPATE TONIGHT. RAIN OVER PRINCE WILLIAM
SOUND AND THE SOUTHEAST MAINLAND WILL BECOME SCATTERED SHOWER LATE
TONIGHT. ISOLATED SHOWERS WILL PERSIST OVER THE KENAI PENINSULA,
ANCHORAGE, MATANUSKA AND SUSITNA VALLEY THROUGH WEDNESDAY.

SOUTHWEST ALASKA...SCATTERED SHOWERS WILL PERSIST OVER THE AREA
THROUGH TUESDAY NIGHT THEN END FROM THE WEST AS THE RIDGE MOVES
INTO THE AREA. RAIN ALONG THE ALASKA PENINSULA WILL BECOME SHOWERS
TONIGHT AS THE LOW CENTERED NEAR DUTCH HARBOR MOVES INTO THE NORTH
PACIFIC TONIGHT.

BERING SEA...THE RIDGE MOVING THROUGH THE BERING SEA WILL KEEP AREAS
OF LOW CLOUDS AND FOG OVER MOST OF THE AREA THROUGH TUESDAY. THE
EXTRA-TROPICAL STORM OVER THE NORTHWEST PACIFIC WILL MOVE INTO THE
WESTERN ALEUTIANS TUESDAY EVENING AND STRENGTHEN AS IT MOVES INTO THE
CENTRAL BERING WEDNESDAY. CURRENT MODELS SHOW STORM FORCE WINDS ARE
POSSIBLE AROUND THIS STORM WEDNESDAY.

.LONG TERM FORECAST...
THE UPPER TROUGH OVER WESTERN ALASKA WILL BEGIN TO FILL AS THE UPPER
RIDGE MOVES INTO WESTERN AND CENTRAL MAINLAND WEDNESDAY NIGHT AND
THURSDAY. SKIES OVER WESTERN ALASKA SHOULD BEGIN TO IMPROVE THROUGH
THE LATTER HALF OF THE WEEK. A SURFACE TROUGH OVER THE GULF OF ALASKA
WILL MAINTAIN SOUTH TO SOUTHEAST FLOW ALONG THE CENTRAL GULF COAST
THROUGH THE REST OF THE WEEK. OCCASIONAL RAIN AND SCATTERED SHOWERS
WILL CONTINUE OVER SOUTH-CENTRAL ALASKA THROUGH THE REST OF THE WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALES 172 175 AND 176.
FIRE WEATHER...NONE.

NM AUG 09