Gale Warning 1022, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
500 AM AKST TUE NOV 30 2010

CORRECTED TYPOS

.ANALYSIS AND UPPER LEVELS...
IN THE UPPER-LVLS...A LARGE UPPER-LOW OVER THE EASTERN GULF OF AK IS
DRIFTING TOWARDS THE SOUTHERN REACHES OF THE ALASKA PANHANDLE AND
FILLING. A STRONG PRESSURE GRADIENT REMAINS IN IT'S WAKE...WITH
RATHER WINDY CONDITIONS STILL BEING EXPERIENCED OVER MUCH OF THE
SOUTHCENTRAL MAINLAND. STRONG SUBSIDENCE AND DRY AIR OVER THE MAT-SU
VALLEY IS DEPICTED ON WATER VAPOR IMAGERY SLOWLY DRIFTING SOUTHEAST
TOWARDS THE NORTHERN GULF COAST. OUT WEST...A FLAT UPPER-RIDGE IS
MOVING THROUGH THE EASTERN ALEUTIANS AND NOSING INTO SW AK...WITH A
SHORT-WAVE RIDGE EMBEDDED IN THE FLOW OVER THE KUSKOKWIM VALLEY AND
BRISTOL BAY. AT THE SURFACE...AN AREA OF LOW PRESSURE NEAR SAINT
LAWRENCE ISLAND IS MOVING EAST AND WEAKENING. AN ASSOCIATED WEAK
FRONT IS SUPPORTING LIGHT SNOW OVER THE KUSKOKWIM DELTA AS DEPICTED
BY RADAR THIS MORNING...BUT STRUGGLING TO MAKE EASTWARD PROGRESS AS
IT RUNS INTO THE AFOREMENTIONED RIDGE. FURTHER WEST...ANOTHER FRONT
IS ENTERING THE WESTERN BERING/ALEUTIANS AND MOVING EAST...AND IS
SPREADING RAIN ACROSS THE CENTRAL CHAIN.

.MODEL DISCUSSION...
MODELS ACCEPTABLY CAPTURE THE SIGNIFICANT WEATHER FEATURES IN THE
AOR. THE NAM SEEMED TO INITIALIZE THE POSITION OF THE LOW IN THE GULF
THE BEST...AS WELL AS THE SCOPE AND DETAILS OF THE RESIDUAL GAP WINDS
ACROSS SOUTHCENTRAL AK AND NORTHERN GULF COAST. OUT WEST...MODELS
SIMILARLY CAPTURE THE LOW NEAR GAMBELL AND ASSOCIATED WEAK FRONT
ALONG THE KUSKOKWIM DELTA COAST DISSIPATING BY THIS EVENING. THE
APPROACH OF THE NEXT FRONT IS ALSO DEPICTED SIMILARLY AS IT LOOKS TO
MOVE ASHORE THE SW MAINLAND LATE WEDNESDAY/EARLY THURSDAY. THOUGH
MODELS AGREE THIS FEATURE WEAKENS AS IT MOVES INLAND...THE LATEST GFS
SOLUTION RETAINS SOME LIGHT QPF INTO SOUTHCENTRAL AK/PRINCE WILLIAM
SOUND ON THURSDAY AS THE SUPPORTING UPPER-LVL SHORTWAVE MOVES
THROUGH. THOUGH FEASIBLE...FOR NOW BELIEVE THAT THE PREXISTING DRY
AIRMASS AND LACK OF RESIDUAL MOISTURE WOULD HAMPER THIS POSSIBILITY.

.SHORT TERM FORECAST...
SOUTHCENTRAL...
WINDY CONDITIONS LOOK TO DIMINISH FROM NORTHWEST TO SOUTHEAST AS THE
STRONGEST SUBSIDENCE DEPARTS AND THE THE LOW IN THE GULF OF AK MOVES
AWAY...RELAXING THE PRESSURE GRADIENT. THE STRONGEST WINDS ARE STILL
THROUGH EASTERN PRINCE WILLIAM SOUND WHERE HIGH WIND WARNINGS ARE
STILL VALID THROUGH LATE MORNING. OTHERWISE A DRY AIRMASS LOOKS TO
LARGELY PROVIDE AMPLE SUNSHINE OVER THE SOUTHERN MAINLAND FOR A
COUPLE MORE DAYS ALONG WITH COOL/CRISP NIGHTS. THE WESTERN BERING
FRONT WILL APPROACH THE FAR WESTERN GULF OF AK LATE WEDNESDAY...WITH
A WAVE OF LOW PRESSURE LOOKING TO DEVELOP ALONG IT NEAR THE SOUTHERN
AKPEN. THIS RESIDUAL/WEAKENING FRONT AND THIS WEAK LOW MAY BRUSH
KODIAK ISLAND WITH SOME SNOW LATE WEDNESDAY AND EARLY THURSDAY.

SOUTHWEST...
LIGHT SNOW OVER THE KUSKOKWIM DELTA TO TAPER TO SNOW SHOWERS THROUGH
TODAY AS THE SYSTEM NEAR GAMBELL DISSIPATES. THE NEXT BERING
FRONT APPROACHES ON WEDNESDAY...WITH INCREASING CHANCES OF SNOW FOR
THE KUSKOKWIM DELTA AND ALSO WITH BRISTOL BAY WEDNESDAY NIGHT.

BERING SEA/ALEUTIANS...
LIGHT RAIN WILL OVERSPREAD THE CENTRAL/EASTERN ALEUTIAN CHAIN AS A
FRONT WORKS EAST THROUGH WEDNESDAY. A MID 970S MB LOW ADVANCES TO
ABOUT 450 NM NORTH OF SHEMYA ON THURSDAY. THIS SYSTEM LOOKS TO BRING
WIDESPREAD GALE TO POSSIBLY STORM-FORCE WINDS TO THE BERING AND
ALEUTIAN CHAIN...ALONG WITH A LARGER MORE SUSTAINED SLUG OF RAIN AND
SNOW LATE WEEK.

.LONG TERM FORECAST...
THE AOR LOOKS TO BECOME DOMINATED BY A BROAD LONG-WAVE TROUGH BY
WEEK'S END...AND THE INFUSION OF A STRONG UPPER-JET LOOKS TO KEEP
THINGS VERY UNSETTLED. FOCUS OF THE FORECAST CHALLENGES WILL CENTER
AROUND THE BERING SEA SYSTEMS...AND THEIR PROGRESSION TOWARDS THE
SOUTHERN MAINLAND.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING...131 135
MARINE...STORM...127
         GALE...351 352 411 412 413 121 126 128 129 130 132 150 155
                165 170 175 176 185
         HEAVY FREEZING SPRAY...121 129 130 132 140
FIRE WEATHER...NONE

JAM NOV 10