Gale Warning 505, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
100 PM AKDT SAT AUG 30 2008

.ANALYSIS AND UPPER LEVELS...A HIGH AMPLITUDE TROUGH IS CENTERED
OVER THE EASTERN BERING SEA EXTENDING FROM A LOW OVER THE CHUKCHI
SEA TO A LOW WEST OF THE PRIBILOFS AND DOWN INTO THE NORTH PACIFIC.
THE LOW AND ITS FRONTAL SYSTEM ARE NEARLY STATIONARY SO RAIN
CONTINUES TO FALL ACROSS THE EASTERN BERING REGION AND THE SOUTHWEST
COAST. A STRONG SHORT-WAVE AND 100KT+ JET STREAK MOVING UP THE EAST
SIDE OF THE TROUGH ARE LEADING TO RAPID DEEPENING OF A SURFACE LOW
WITH A TRACK TOWARD KODIAK ISLAND. A SHORT-WAVE RIDGE AHEAD OF THIS
IS AMPLIFYING OVER MAINLAND ALASKA RESULTING IN SUNNY SKIES ACROSS
SOUTHCENTRAL.

.MODEL DISCUSSION...MODELS INITIALIZED WELL AND ARE IN DECENT
AGREEMENT WITH HANDLING OF THE DEVELOPING NORTH PACIFIC LOW. THIS
IS A CHANGE FROM MODEL SOLUTIONS ON FRIDAY WHICH INDICATED A TRACK
TO KODIAK ISLAND THEN EASTWARD. NOW THE LOW TRACK IS WESTWARD FROM
KODIAK ISLAND AS A SHORT-WAVE DROPS INTO THE WESTERN BERING AND
MAINTAINS THE MEAN TROUGH POSITION OVER THE BERING. THE CURRENT
FORECAST LARGELY REFLECTS THIS NEW TRACK...BUT SOME FINE-TUNING
OF WINDS WILL BE MADE. THE AFFECT OF THIS WILL ALSO BE TO FORCE
THE NEXT LOW THAT DEVELOPS SOUTH OF THE ALEUTIANS FARTHER EAST
THAN YESTERDAY...TOWARD KODIAK ISLAND. MODEL SOLUTIONS DIFFER A
BIT ON THE SPEED AND TRACK OF THIS LOW...BUT THE GFS IS PREFERRED
DUE TO GOOD RUN-TO-RUN CONSISTENCY SINCE THE 00Z RUN YESTERDAY.

.SHORT TERM FORECAST...

SOUTHCENTRAL...THE DEVELOPING PACIFIC STORM WILL BE THE STRONGEST
IN QUITE SOME TIME. EXPECT WINDS TO COME UP QUICKLY ACROSS THE GULF
WATERS LATE THIS EVENING THROUGH SUNDAY MORNING WITH WIDESPREAD
GALES AS WELL AS STORM FORCE GUSTS THROUGH SHELIKOF STRAIT. ALSO
EXPECT VERY HIGH SEAS SOUTH AND EAST OF KODIAK ISLAND ON SUNDAY
WITH A MAXIMUM SIGNIFICANT WAVEHEIGHT AROUND 25 FEET. WINDS WILL
GRADUALLY DIMINISH SUNDAY NIGHT AND MONDAY AS THE LOW MOVES OVER
KODIAK ISLAND AND WEAKENS. RAIN WILL MOVE IN SUNDAY AND REMAIN
PRIMARILY ALONG THE COAST WITH JUST A FEW SHOWERS ASSOCIATED WITH
WEAK UPPER WAVES MAKING IT INLAND. THE NEXT SYSTEM IS EXPECTED TO
REACH KODIAK ISLAND LATE TUESDAY...SO THERE WONT BE MUCH BREAK(IF
ANY)IN THE RAIN ALONG THE COAST. AT THIS POINT IT LOOKS LIKE THIS
SYSTEM MAY MAKE MORE NORTHWARD PROGRESSION AND BRING RAIN TO INLAND
AREAS.

SOUTHWEST...AS THE DEVELOPING LOW APPROACHES THE REGION TONIGHT
FLOW WILL GRADUALLY SHIFT TO THE EAST CAUSING MOST OF THE RAIN
CURRENTLY BEING OBSERVED ALONG THE SOUTHWEST COAST TO END.
HOWEVER...RAIN WILL QUICKLY MOVE INTO BRISTOL BAY LATE TONIGHT
INTO SUNDAY MORNING WITH SOME LIGHT RAIN OR SHOWERS SPREADING
NORTH AND WEST SUNDAY AFTERNOON TOWARD THE KUSKOKWIM DELTA AND
SOUTHERN KUSKOKWIM VALLEY. THE LOW WILL REACH ITS MAXIMUM STRENGTH
NOT TOO FAR TO THE SOUTH OF KODIAK ISLAND...SO EXPECT STRONG GAP
WINDS TO DEVELOP THROUGH THE ALASKA PENINSULA LATE TONIGHT AND
CONTINUE THROUGH THE DAY SUNDAY. SHOWERS WILL CONTINUE SUNDAY NIGHT
THROUGH TUESDAY AS THE SURFACE LOW MOVES OVER BRISTOL BAY AND
CONTINUES TO WEAKEN. THE NEXT SYSTEM WILL BRING ANOTHER GOOD SHOT
OF RAIN BY LATE TUESDAY.

BERING SEA/ALEUTIANS...THE LOW IN THE CENTRAL BERING WILL QUICKLY
DISSIPATE TONIGHT AS THE DEVELOPING LOW BECOMES DOMINANT.
HOWEVER...WITH UPPER TROUGH REMAINING OVERHEAD SHOWERS WILL PERSIST
ACROSS THE REGION. A NEW SYSTEM SOUTH OF THE KAMCHATKA PENINSULA
WILL TRACK SOUTH OF THE ALEUTIANS TONIGHT THROUGH MONDAY. BASED ON
THIS TRACK ONLY IMPACT WILL BE A BIT OF WIND SOUTH OF THE ALEUTIANS.

.LONG TERM FORECAST...THE GFS 500MB 5-WAVE SHOWS THE UPPER TROUGH
REMAINING CENTERED OVER THE EASTERN BERING AND WESTERN ALASKA
THROUGH THE EXTENDED FORECAST PERIOD AND BEYOND. THEREFORE...DONT
EXPECT A WHOLE LOT OF CHANGE FROM CURRENT PATTERN. AS WOULD BE
EXPECTED MOVING INTO THE FALL SEASON THE ATMOSPHERE IS BECOMING
MORE BAROCLINIC AND STORMS ARE GETTING STRONGER.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING...120 130 132 138 150 155.
FIRE WEATHER...NONE.

SEB AUG 08