Small Craft Advisory 136, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
240 PM AKST SAT FEB 19 2011

.ANALYSIS AND UPPER LEVELS...
ACTIVE PATTERN CONTINUES. THE STORM THAT BROUGHT SOUTHCENTRAL THE
SIGNIFICANT SNOW YESTERDAY IS QUICKLY MOVING EAST. THE DEFORMATION
ZONE ASSOCIATED WITH THAT SYSTEM IS NEAR CORDOVA AND THE EASTERN
COPPER RIVER BASIN. A TRANSITORY RIDGE IS IN PLACE OVER THE
INTERIOR TODAY WHILE ANOTHER STRONG SYSTEM APPROACHES THE BERING
COAST THIS EVENING.

.MODEL DISCUSSION...
MODELS IN EXCELLENT AGREEMENT THROUGH 84 HOURS SO NO CHANGES ARE
EXPECTED WITH THE UPCOMING FORECAST PACKAGE. WHILE THE GFS AND ECMWF
ARE IN AGREEMENT WITH THE DEVELOPING HIGH AMPLITUDE RIDGE DURING THE
MIDDLE OF THIS NEXT WEEK...THE SURFACE PATTERN IS DRASTICALLY
DIFFERENT. THE CURRENT EXTENDED FORECAST IS ADVERTISING THIS GENERAL
PATTERN CHANGE...BUT WILL HAVE TO CONTINUE TO ADJUST THE TIMING AND
STRENGTH OF THE LOWS OUT WEST WEDNESDAY THROUGH FRIDAY.

.SHORT TERM FORECAST...
SNOW IS TAPERING OFF OVER THE MOST EASTERN PART OF OUR DOMAIN EARLY
THIS AFTERNOON WHILE CLEAR SKIES DOMINATE THE MAJORITY OF THE INLAND.
WINDS THROUGH THE NORMAL CHANNELED AREAS HAVE INCREASED AND WILL
CONTINUE TO STRENGTHEN AS THE GRADIENT INCREASES LATER THIS
AFTERNOON. THE RECENT SNOWFALL OVER NORTHEASTERN PRINCE WILLIAM SOUND
COMBINED WITH THE STRONG WINDS WILL RESULT IN BLIZZARD CONDITIONS
THROUGH THOMPSON PASS. HIGH PRESSURE QUICKLY TRANSITIONS TO THE EAST
AHEAD OF AN APPROACHING SYSTEM OUT WEST. CLOUDS WILL BE ON THE
INCREASE AGAIN OVERNIGHT WITH SCATTERED SNOW SHOWERS POSSIBLE THROUGH
THE REST OF THE WEEKEND.

.SOUTHWEST ALASKA...THE MOST SIGNIFICANT WEATHER WILL BE OUT WEST
WITH A RAPIDLY APPROACHING FRONTAL BOUNDARY. STRONG SOUTHWESTERLY
WINDS WILL USHER THE MOISTURE INLAND THIS EVENING...BRINGING BLIZZARD
CONDITIONS ACROSS THE KUSKOKWIM DELTA. THE SNOW AND WIND WILL SPREAD
FURTHER INLAND INCLUDING THE BRISTOL BAY ZONE. WHILE LOCAL AREAS OF
BLOWING SNOW WILL REDUCE VISIBILITY...NOT EXPECTING BLIZZARD
CONDITIONS IN THE LOWER KUSKOKWIM VALLEY OR BRISTOL BAY ZONE TONIGHT.
SNOW TAPERS OFF SUNDAY WITH SHOWERS REMAINING ALONG THE WESTERN
FOOTHILLS OF THE ALASKA RANGE THROUGH SUNDAY NIGHT.

HIGH PRESSURE AGAIN BUILDS OVER SOUTHWEST ALASKA MONDAY AND LASTS
THROUGH TUESDAY...BRINGING TRANQUIL WEATHER TO THE REGION.

.ALEUTIANS/BERING SEA...THE STRONG FRONT THAT BROUGHT NEAR HIGH WIND
WARNING LEVEL WINDS TO THE WESTERN ALEUTIANS IS RAPIDLY BECOMING
ELONGATED AS MUCH OF ITS ENERGY MOVES TO THE NORTHEAST TOWARD THE
SEWARD PENINSULA. BROAD WESTERLY FLOW WILL DIMINISH DURING THE
WEEKEND AS A RIDGE BUILDS OVER THE CENTRAL AND EASTERN BERING SEA
THROUGH EARLY NEXT WEEK. A SERIES OF WEAK DISTURBANCES WILL SKIRT THE
WESTERN ALEUTIANS MONDAY AND TUESDAY BEFORE A STRONGER LOW IMPACTS
THE REGION MID WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 131 155.
MARINE...STORM WARNING...176 185 411 412
         GALE WARNING...120 127 129 130 132 138 150 160 165 170 172
175 179 180 413 414 351 352.
         HEAVY FREEZING SPRAY WARNING...185.
FIRE WEATHER...NONE

AB FEB 11