Gale Warning 728, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AKST MON NOV 17 2008

.ANALYSIS AND UPPER LEVELS...
FAIRLY QUIET SETUP OVER THE REGION THIS MORNING. A 998 MB LOW JUST
SOUTH OF UMNAK ISLAND THIS MORNING WILL CONTINUE TO MOVE FURTHER
SOUTH INTO THE NORTH PACIFIC. HIGH PRESSURE IS BEGINNING TO
INTENSIFY FROM THE NORTHERN BERING INTO THE INTERIOR...WITH COLDER
AND DRIER NORTHERLY OFFSHORE FLOW DEVELOPING OVER THE SOUTHERN
MAINLAND.

.MODEL DISCUSSION...
SOME ISSUES WITH THE MODELS BEGINNING AROUND TUESDAY NIGHT AND
WEDNESDAY MORNING. SOME RUNS OF VARIOUS MODELS HAVE BROUGHT A SPOKE
OF THE LOW COMPLEX IN THE NORTH PACIFIC NORTH INTO THE GULF OF
ALASKA MIDWEEK. WE ARE KEEPING THE LOW COMPLEX SOUTH OF THE GULF OF
ALASKA AND KEEPING THE NORTHERN GULF DRY THROUGH WEDNESDAY. ALSO
THERE ARE SOME SIGNIFICANT ISSUES WITH THE MODELS LATE IN THE WEEK
IN HOW QUICKLY AND DRAMATICALLY THEY BREAK DOWN THE STRONG
RIDGE/OMEGA BLOCK IN THE EASTERN BERING. UNTIL THE MODELS SETTLE
DOWN A BIT...WE STAYED WITH THE PREVIOUS FORECAST WHICH WAS FAIRLY
CLOSE TO THE 0Z ECMWF FROM THE 16TH...THOUGH THE ECMWF HAS CHANGED
SINCE THEN.

.SHORT TERM FORECAST...
SOUTHCENTRAL...
DRY FORECAST THROUGH WEDNESDAY FOR SOUTHCENTRAL...WITH THE POSSIBLE
EXCEPTION OF A FEW SHOWERS NEAR KODIAK AND A FEW LINGERING FLURRIES
THIS MORNING OVER MAINLAND SOUTHCENTRAL. THE TWO LARGEST FORECAST
CHALLENGES WILL BE THE SPEED OF THE CLEARING TODAY AND HOW GUSTY THE
WINDS GET THROUGH CHANNELED TERRAIN. THE TREND THROUGH WEDNESDAY
WILL DEFINITELY BE FOR CLEARING...COOLING...AND INCREASING WINDS
THROUGH CHANNELED TERRAIN AS HIGH PRESSURE STRENGTHENS IN THE
INTERIOR ALONG WITH A STATIONARY COMPLEX AREA OF LOW PRESSURE JUST
SOUTH OF THE GULF OF ALASKA. MANY AREAS ALONG THE NORTH GULF COAST
HAVE ALREADY CLEARED OUT FOR GOOD...INCLUDING WHITTIER SEWARD AND
VALDEZ WHERE CHANNELED DOWNSLOPING WINDS HAVE ALREADY PICKED UP. LOW
CLOUDS WILL BE SLOWER TO CLEAR IN THE COOK INLET REGION AND THE
COPPER RIVER BASIN. FOR THE COOK INLET REGION...BELIEVE THERE WILL
BE SOME CLEARING THIS AFTERNOON...BUT SOME REDEVELOPMENT OF LOW
CLOUDS AND FOG TONIGHT.

SOUTHWEST MAINLAND...
LIKE SOUTHCENTRAL...THE SOUTHWEST MAINLAND WILL SEE PROGRESSIVELY
COLDER...CLEARER...AND BREEZIER CONDITIONS THROUGH WEDNESDAY AS THE
OFFSHORE PRESSURE GRADIENT INCREASES. LOW CLOUDS WILL BE A LITTLE
STUBBORN TO CLEAR OUT. MOST AREAS WILL CLEAR OUT TUESDAY AFTERNOON.

BERING SEA/ALEUTIANS...
LOW PRESSURE JUST SOUTH OF UMNAK ISLAND WILL CONTINUE TO MOVE SOUTH
AND AWAY FROM THE AREA AND MERGE WITH A SEMIPERMANENT COMPLEX AREA
OF LOW PRESSURE IN THE NORTH PACIFIC SOUTH OF THE ALASKA PENINSULA
AND GULF OF ALASKA. A BLOCKING HIGH PRESSURE WILL DEVELOP TODAY OVER
THE NORTHERN BERING AND PERSIST THROUGH WEDNESDAY. ONCE THE LOW
SOUTH OF UMNAK ISLAND KICKS OUT...MOST AREAS WILL BE DRY TUESDAY AND
WEDNESDAY. AN EXCEPTION IS THE WESTERN ALEUTIANS WHICH WILL BE
GRAZED BY PRECIPITATION FROM SYSTEMS TO THEIR WEST TRYING TO MOVE
EAST INTO THE BERING RIDGE BUT HAVING LITTLE SUCCESS.

.LONG TERM FORECAST...
NOT MUCH CONFIDENCE IN THE LONG TERM...NAMELY WHETHER OR NOT THE
STRONG BERING HIGH PRESSURE BREAKS DOWN AND IF IT DOES...WHEN THAT
HAPPENS. IT DOES LOOK LIKE SOME PRETTY DECENT SYSTEMS WILL PUSH INTO
THE CENTRAL BERING THURSDAY OR FRIDAY...BUT WHETHER OR NOT THEY CAN
REACH THE EASTERN BERING AND TOTALLY BREAK DOWN THE HIGH PRESSURE IS
ANOTHER STORY. FOR THE SOUTHERN MAINLAND...THE OFFSHORE PRESSURE
GRADIENT LOOKS TO PEAK AROUND THURSDAY OR THURSDAY NIGHT ALONG WITH
THE COLDEST AIRMASS OVER THE REGION. WHAT HAPPENS FRIDAY AND BEYOND
IS A BIG QUESTION WITH POOR MODEL AGREEMENT AND CONSISTENCY AT BOTH
THE SURFACE AND ALOFT. AT THE LEAST IT LOOKS LIKE A TREND TOWARD
AND WARMER AND WETTER WILL BEGIN FRIDAY INTO THE
WEEKEND...ESPECIALLY FOR THE GULF AND SOUTHCENTRAL.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING ZONES 172 176 411 412.
FIRE WEATHER...NONE.

FOISY NOV 08