Gale Warning 429, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AKDT TUE MAY 25 2010

.ANALYSIS AND UPPER LEVELS...RELATIVELY STAGNANT SYNOPTIC PATTERN
CONTINUES...FEATURING A BROAD LONGWAVE TROUGH THROUGHOUT THE WHOLE
BERING/MAINLAND REGION...WITH INTRUDING SHORTWAVE RIDGES OVER
INTERIOR ALASKA AND THE CENTRAL BERING SEA. THE HIGH PRESSURE OVER
INTERIOR ALASKA IS BRINGING WARM AIR AND CLEAR SKIES TO MOST
AREAS...AS WELL AS THE THREAT OF AFTERNOON AND EVENING THUNDERSTORMS.

THE WEAK UPPER LOW OVER BRISTOL BAY IS WEAKENING AND MOVING SLOWLY
SOUTHWARD...BUT IS CONTINUING TO BRING SHOWERS TO THE REGION THIS
MORNING.

IN THE BERING SEA/ALEUTIANS...HIGH PRESSURE IS HAVING THE EFFECT OF
PRODUCING WIDESPREAD FOG AND STRATUS THAT HAS PERSISTED FOR SEVERAL
DAYS THROUGHOUT THE ENTIRE REGION. IMPINGING ON THIS HIGH PRESSURE
ARE TWO LOWS. THE FIRST IS A 994 MB LOW THAT HAD MOVED TO ABOUT 500
MILES SOUTHWEST OF SHEMYA AND HAS NOW BEGUN TO WEAKEN AND MOVE AWAY.
A SUBSEQUENT TRIPLE POINT LOW IS DEVELOPING ALONG THE ASSOCIATED
FRONT...AND IS CURRENTLY LOCATED SOUTH OF THE CENTRAL ALEUTIANS. THIS
FEATURE IS MOVING NORTHWARD. MEANWHILE...A WEAK VERTICALLY STACKED
LOW IS MOVING SOUTHWARD FROM FAR NORTHEASTERN RUSSIA INTO THE BERING
SEA.

.MODEL DISCUSSION...MODELS ARE IN EXCELLENT SYNOPTIC AGREEMENT
THROUGH EARLY NEXT WEEK. THERE ARE SOME MODEL DIFFERENCES REGARDING
THE EXACT STRUCTURE AND SPEED OF THE DEVELOPING TRIPLE POINT LOW
SOUTH OF THE ALEUTIANS. NEVERTHELESS...ALL MODELS DO AGREE THAT THIS
FEATURE WILL DEVELOP INTO THE DOMINANT LOW IN THE REGION FOR THE
WEEK...AND IS EXPECTED TO MOVE SLOWLY EASTWARD TOWARD THE EXTREME
SOUTHWESTERN GULF BY THE WEEKEND.

.SHORT TERM FORECAST...
.MAINLAND ALASKA...GENERAL HIGH PRESSURE WILL REMAIN THE MAIN WEATHER
FEATURE FOR THE NEXT FEW DAYS. THE REMNANTS OF YESTERDAYS
THUNDERSTORMS OVER THE COPPER RIVER BASIN ARE STILL MOVING OVER THE
TALKEETNA AND CHUGACH MOUNTAINS THIS MORNING...BUT SHOULD CLEAR THE
AREA BY LATE MORNING AND ALLOW TEMPERATURES TO WARM INTO THE 60S OR
LOW 70S IN MOST LOCATIONS AGAIN. ADDITIONALLY...THE THERMAL TROUGH
NOTED ALONG AND JUST SOUTH OF THE ALASKA RANGE YESTERDAY SHOULD SAG A
BIT FURTHER SOUTH TODAY...BRINGING A CHANCE OF THUNDERSTORMS AS FAR
SOUTH AS THE KENAI PENINSULA AND PERHAPS EVEN INLAND BRISTOL BAY
TODAY. MARINE STRATUS HAS CREPT BACK INTO PARTS OF THE KUSKOKWIM
DELTA AND BRISTOL BAY ZONE THIS MORNING...AND WILL BE SLOW TO VACATE
THE AREA. THIS SHOULD INHIBIT SIGNIFICANT DAYTIME HEATING AND MOST
AFTERNOON CONVECTIVE ACTIVITY IN THESE AREAS.

.BERING SEA/ALEUTIANS...HIGH PRESSURE WITH WIDESPREAD FOG AND STRATUS
WILL LINGER FOR ONE MORE DAY BEFORE A LOW COMING UP FROM THE SOUTH
BEGINS TO CHANGE THE OVERALL PATTERN. WINDS WILL SWITCH TO THE
SOUTHEAST AND INCREASE ACROSS THE CENTRAL AND EASTERN ALEUTIANS THIS
AFTERNOON AND OVERNIGHT. THIS WILL HELP BREAK UP THE ENTRENCHED
MARINE STRATUS...AND ALSO BRING RAINS BACK TO THE EASTERN HALF OF THE
CHAIN STARTING WEDNESDAY. GALE FORCE WINDS SPREAD NORTH TO THE
PRIBILOF ISLANDS WEDNESDAY EVENING AS THE LOW CENTER APPROACHES ATKA.
THIS LOW WILL BE SLOW TO MOVE OUT...AND DRIFT SLOWLY EAST THROUGH THE
END OF THE WEEK.

.LONG TERM FORECAST...WHILE THE BERING LOW WILL BRING A RETURN TO
ACTIVE WEATHER IN THAT REGION...HIGH PRESSURE WILL STAY LARGELY
INTACT OVER MUCH OF MAINLAND ALASKA. THIS MEANS CONTINUED DIURNAL
CONVECTIVE ACTIVITY IS LIKELY...ESPECIALLY OVER MOUNTAINOUS
AREAS...WITH TEMPERATURES AT OR ABOVE NORMAL THROUGH THE WEEKEND.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...NONE
FIRE WEATHER...RED FLAG WARNING 141

AMD MAY 10