Gale Warning 597, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
300 PM AKDT TUE OCT 21 2008

.MODEL DISCUSSION...
MODELS IN REASONABLY GOOD AGREEMENT THROUGH 72 HOURS. GFS IS THE MOST
AGGRESSIVE IN MOVING THE GULF OF ALASKA LOWS INLAND. WE PREFER THE
NAM AND ECMWF SOLUTIONS...ESPECIALLY AT 60 HOURS WHEN GFS TRIES TO
MOVE THE GULF OF ALASKA LOW RAPIDLY INLAND NEAR YAKUTAT WHILE ECMWF
HOLDS THE LOW BACK CLOSER TO MIDDLETON ISLAND.
ALL MODELS FAILED TO INITIALIZE THE MOISTURE FIELD WELL...ESPECIALLY
IN THE LOWER LEVELS. GFS FAILS TO RECOGNIZE THE BROAD BAND OF
STAGNANT STRATUS/STRATOCUMULUS ACROSS INTERIOR PORTIONS OF SOUTHERN
ALASKA AND RELATED SHOWERS ALMOST ENTIRELY. NAM DOES BETTER BUT POPS
ARE TOO HIGH. BOTH THE GFS AND NAM MORNING MOS PACKAGES ARE SUSPECT.

.SURFACE FEATURES...
THREE STRONG LOWS EACH WITH GOOD UPPER LEVEL SUPPORT WILL BE
IMPACTING THE ANCHORAGE AREA OF RESPONSIBILITY WITHIN THE NEXT 60
HOURS.
LOW NO 1...A 976 MB LOW IN THE SOUTHERN GULF OF ALASKA WILL
STRENGTHEN TO 967 MB JUST SOUTHEAST OF MIDDLETON ISLAND TUE NIGHT
THEN WEAKEN AND MOVE INLAND NEAR YAKUTAT WED EVENING.
LOW NO 2...A 961 MB IN THE NORTHWEST PACIFIC WILL INTENSIFY TO 951 MB
JUST SOUTH OF ADAK TUE NIGHT THEN DISSIPATE IN THE SOUTHEASTERN GULF
OF ALASKA THU MORNING. THE ASSOCIATED OCCLUDED FRONT WILL GRAZE THE
WESTERN ALEUTIANS THIS EVENING THEN MOVE OVER THE CENTRAL AND EASTERN
ALEUTIANS BY MORNING.
LOW NO 3...A 984 TRIPLE POINT LOW WILL DEVELOP 180 NM SOUTHEAST OF
CHIGNIK WED EVENING AND INTENSIFY TO 971 MB NEAR MIDDLETON ISLAND THU
AFTERNOON. THE ASSOCIATED COLD FRONT WILL SLIDE ACROSS SOUTHERN
KODIAK ISLAND THURSDAY NIGHT.

.SHORT TERM FORECAST...
MOST OF THE PRECIP FROM LOW NO 1 SHOULD REMAIN TO THE EAST OF THE
ANCHORAGE AOR...BUT WRAP AROUND PRECIP ASSOCIATED WITH NORTHEASTERLY
SURFACE FLOW IS A CONCERN TONIGHT ACROSS PRINCE WILLIAM SOUND AND THE
EASTERN COPPER RIVER BASIN.
PLENTY OF RAIN AND HIGH WINDS ARE EXPECTED FOR THE ALEUTIAN CHAIN
BEGINNING TONIGHT AND CONTINUING THROUGH MOST OF WEDNESDAY AS LOW NO
2 PASSES JUST SOUTH OF THE AREA. SEE LATEST WWAK72 NPWALU FOR
DETAILS.
COLD AIR ADVECTION AND SNOW SHOWERS ON THE BACKSIDE OF LOW NO 3 WILL
IMPACT KODIAK ISLAND...THE ALASKA PENINSULA...EASTERN ALEUTIANS...AND
EASTERN BERING SEA WEDNESDAY NIGHT AND THURSDAY. THE LOW CENTER
ITSELF IS EXPECTED TO BE POSITIONED NEAR MIDDLETON ISLAND THURSDAY
AFTERNOON. THIS IS A GOOD PATTERN FOR SNOW FOR THE PRINCE WILLIAM
SOUND AREA...WITH WARM MOIST SOUTHERLY FLOW ALOFT COUPLED WITH COOL
NORTHEASTERLY FLOW IN THE LOWEST LEVELS.

.LONG TERM FORECAST...
UPPER LEVEL PATTERN REMAINS DYNAMIC...USHERING IN A SERIES OF
MODERATE LOWS OUT OF THE NORTH PACIFIC AND INTO THE GULF OF ALASKA.
OUT WEST...UPPER LEVEL RIDGING AND WEAK NORTHWESTERLY FLOW AT THE
SURFACE WILL BRING COOLER AND EVEN MORE WINTER LIKE CONDITIONS TO
SOUTHWEST ALASKA AND THE BERING SEA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING 186 191 185.
MARINE...GALES  120 130 132 150 160 179 411 412
         STORMS 413 414 155 165 170 171 176
         HURRICANE FORCE  172 175
FIRE WEATHER...NONE.

ASB OCT 08