Flood Watch 5, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 AM AKDT WED AUG 26 2009

CORRECTION FOR TYPO

.MODEL DISCUSSION...GFS AND NAM 00Z RUNS IN GOOD AGREEMENT THROUGH 60
HOURS ON PRIMARY WEATHER FEATURES.  THOSE FEATURES ARE A NORTH
PACIFIC LOW THAT MOVES INTO THE SOUTHERN GULF OF AK THURSDAY AND
MOVES NORTHWESTWARD TO THE SOUTHERN TIP OF KODIAK ISLAND ON FRIDAY
AFTERNOON. A CENTRAL ALEUTIAN LOW MOVES WELL SOUTH OF COLD BAY ON
FRIDAY AS IT STRENGTHENS TO 976 MB. A RIDGE OF HIGH PRESSURE FORMS
OVER THE WESTERN ALEUTIANS AND CENTRAL BERING SEA WEDNESDAY NIGHT AND
PERSISTS THROUGH SUNDAY AS IT SLOWLY MOVES TO THE SOUTHEAST.
FORECASTERS THIS MORNING FAVORING GFS SOLUTION IN THEIR VARIOUS
PRODUCTS.

.ANALYSIS AND UPPER LEVELS...MAIN UPPER LEVEL ENERGY IS ASSOCIATED
WITH THE CENTRAL ALEUTIAN LOW WHICH DIGS INTO THE NORTH PACIFIC LATER
IN THE WEEK WHICH IN TURN ALLOWS FOR THE DEVELOPMENT OF SURFACE LOW
IN THE GULF OF ALASKA OVER THE WEEKEND.  HIGH AMPLITUDE RIDGE OVER
THE NORTHWEST COAST OF NO. AM. WILL BLOCK ANY MOVEMENT FURTHER
EASTWARD.

.SHORT TERM FORECAST...EXPECTING MOISTURE TO MOVE INTO SOUTHCENTRAL
WEDNESDAY MORNING AS A RESULT OF SOUTHEAST FLOW ALOFT.  SOUTHWEST
ZONES SHOULD NOT EXPECT PRECIPITATION FROM CURRENT CENTRAL ALEUTIAN
STORM WITH THE EXCEPTION OF THE NORTHERN AK PEN ON LATE WEDNESDAY AND
THURSDAY.  KODIAK ISLAND CAN EXPECT RAIN BEGINNING WEDNESDAY NIGHT
AND EXTENDING THROUGH FRIDAY NIGHT...STRONG NE WINDS THURSDAY
AFTERNOON THROUGH FRIDAY MORNING.

.LONG TERM FORECAST...WITH A GULF OF ALASKA LOW ON THE WEEKEND AND
RIDGE OF HIGH PRESSURE OVER THE CENTRAL BERING MOST OF THE ACTIVE
WEATHER WILL BE IN SOUTHCENTRAL. RAIN OR SHOWERS IN COASTAL AREAS OF
SOUTHCENTRAL BUT GENERALLY CLOUDY ON SATURDAY BECOMING MOSTLY SUNNY
OVER MUCH OF THE AREA ON SUNDAY.

ON MONDAY A TROUGH FORMS OVER THE BERING SEA AND HENCE TRANSPORTS
MOISTURE INTO THE SOUTHWEST ZONES BEGINNING MONDAY AFTERNOON.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALES 155 165 171 176 179 138  STRM 175 172 120 130 132
FIRE WEATHER...GONE UNTIL NEXT YEAR

JMP AUG 09