Small Craft Advisory 268, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM ADT TUE MAR 20 2007

.DISCUSSION...
MODELS IN GOOD AGREEMENT THROUGH THURSDAY AFTERNOON BUT THE SOLUTION
DIVERGE BEYOND THAT POINT. THE MAIN DIFFERENCE IS A LOW SOUTH OF THE
ALASKA PENINSULA THURSDAY AFTERNOON. THE GFS MOVES IT FASTER THAN THE
NAM MODEL INTO THE GULF OF ALASKA. THE GFS APPEARS TO HAVE THE BETTER
SOLUTION SINCE IT IS IN BETTER AGREEMENT WITH THE UKMET AND THE
CANADIAN GLOBAL MODELS.

UPPER AIR...
THE MAIN ARCTIC LOW WILL REMAIN OVER THE ARCTIC OCEAN THROUGH
THURSDAY WILL A FEW SHORT WAVES MOVING ALONG ITS EDGES. A WEAK SHORT
WAVE TROUGH SOUTH OF THE ALASKA PENINSULA WILL MOVE INTO THE NORTHERN
GULF OF ALASKA WEDNESDAY MORNING THEN DISSIPATE NEAR CAPE YAKATAGA IN
THE AFTERNOON. AN STRONGER TROUGH OVER NORTHWEST ALASKA WILL MOVE
INTO THE SOUTHWEST INTERIOR WEDNESDAY AND WILL WEAKEN OVER THE
SUSITNA VALLEY AND COOK INLET WEDNESDAY NIGHT AND THURSDAY MORNING.

EAST DOMAIN...
A STRONG SURFACE LOW SOUTH OF THE ALASKA PENINSULA WILL MOVE INTO THE
WESTERN GULF OF ALASKA TONIGHT AND WILL MOVE INTO THE COPPER RIVER
BASIN WEDNESDAY AFTERNOON. THE WEATHER FRONT SOUTH OF KODIAK ISLAND
WILL WEAKEN NEAR THE CENTRAL GULF COAST TONIGHT. SNOW AND STRONG
WINDS ALONG AND JUST AHEAD OF THE FRONT WILL CREATE AREAS OF BLOWING
SNOW ALONG THE CENTRAL GULF COAST AND PARTS OF PRINCE WILLIAM SOUTH
AND THE EASTERN KENAI PENINSULA. A FEW AREAS OF BLIZZARD CONDITIONS
MAY  DEVELOP THROUGH PORTAGE VALLEY TONIGHT. SNOW OVER KODIAK ISLAND
WILL CHANGE TO SHOWERS THIS EVENING AS WINDS BECOME NORTHWEST BEHIND
THE LOW.

THE UPPER TROUGH MOVING INTO THE SUSITNA VALLEY WEDNESDAY NIGHT
SHOULD BRING MORE SNOW INTO THE SUSITNA VALLEY, ANCHORAGE BOWL AND
THE KENAI PENINSULA WEDNESDAY NIGHT.

WEST DOMAIN...
THE LOW SOUTH OF THE ALASKA PENINSULA WILL CONTINUE TO MOVE NORTHEAST
INTO THE GULF OF ALASKA TONIGHT. GUSTY NORTH WINDS ALONG THE BACK
SIDE OF THE LOW WILL CREATE AREAS OF BLOWING SNOW ALONG THE WINDIER
SECTIONS OF THE PENINSULA TONIGHT. SNOW OVER BRISTOL BAY WILL
CONTINUE THROUGH THIS EVENING AND BECOME SHOWERS AFTER MIDNIGHT.
AREAS OF LIGHT SNOW WILL MOVE INTO THE KUSKOKWIM VALLEY TONIGHT.

NORTHERLY FLOW OVER THE BERING SEA WILL WEAKEN AS A WEAK LOW PRESSURE
SYSTEM DEVELOPS OVER THE CENTRAL BERING WEDNESDAY NIGHT. AN AREA OF
LOW PRESSURE SOUTH OF ATTU WILL MOVE EAST, JUST SOUTH OF THE ALEUTIAN
CHAIN, TO ABOUT 250 MILES SOUTH OF NIKOLSKI THURSDAY AFTERNOON. SNOW
SHOWERS WILL PERSIST ALONG THE ALEUTIANS THROUGH THURSDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNINGS 125 181.
MARINE...STORM WARNING 120
         GALE WARNING 125, 130, 132, 138, 140, 141, 150, 155, 160,
                      170, 172, 176, 179
FIRE WEATHER...NONE.

NM MAR 07