Small Craft Advisory 163, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 PM AKST WED MAR 2 2011

.MODEL DISCUSSION...MODELS FROM THE 12Z RUN ARE DOING WELL AND HAVE
LOCKED ON BY ALL THE MAIN FEATURES. THERE IS THE TYPICAL PROBLEMS IN
DEALING WITH INDIVIDUAL WAVES IN THE COMPLEX LOW THAT WILL DEVELOP IN
THE SOUTHERN GULF OF ALASKA BUT THIS LOOKS TO HAVE VERY LITTLE IMPACT
ON THE FORECAST.

.ANALYSIS AND UPPER LEVELS...HIGH PRESSURE CONTINUES TO DOMINATE THE
BERING SEA CREATING AN UPPER LEVEL GRADIENT WITH A DEEP LOW SOUTH OF
THE GULF OF ALASKA. THIS GRADIENT IS PROVIDING NORTHERLY WINDS OVER
MAINLAND ALASKA IN THE MID AND UPPER LEVELS. THE JET WHICH IS MOVING
SOUTH OVER MAINLAND ALASKA IS ALSO RELATIVELY WEAK WITH SPEEDS
PRIMARILY LESS THAN 75 KNOTS. THERE IS LITTLE MID AND UPPER LEVEL
MOISTURE IN THE REGION KEEPING THESE LEVELS VOID OF MOST CLOUD COVER.
THE SURFACE HIGH REMAINS IN THE CENTRAL BERING SEA AND A LOW MOVING
INTO THE SOUTHEAST GULF OF ALASKA IS ONCE AGAIN TIGHTENING THE
PRESSURE GRADIENT ALONG THE NORTH GULF COAST.

.SHORT TERM FORECAST...WINDS ARE BEGINNING TO INCREASE AGAIN OVER
MUCH OF THE MAINLAND FORECAST AREA AS THE SURFACE PRESSURE GRADIENT
INCREASES AND UPPER LEVEL SUPPORT RETURNS. THE STRONGEST WINDS ARE
EXPECTED TO BE IN THE MATANUSKA VALLEY BEGINNING AFTER MIDNIGHT
TONIGHT WITH A HIGH WIND WARNING IN EFFECT FOR WINDS UP TO 75 MPH.
WINDS IN THE VALDEZ AREA AND THOMPSON PASS HAVE COME UP AND THIS AREA
MIGHT ALSO NEED A HIGH WIND WARNING.
SOUTHWEST ALASKA WILL ALSO SEE A TIGHTENING PRESSURE GRADIENT
INCREASING WINDS OVERNIGHT EXCEPT IN AREAS WHERE A GOOD INVERSION CAN
DEVELOP WHICH WILL DELAY THE ONSET OF THE INCREASING WINDS UNTIL
TOMORROW.

.LONG TERM FORECAST...THE NORTHWARD PROGRESSION OF THE RIDGE FROM THE
CENTRAL BERING SEA INTO THE ARCTIC OCEAN SHOULD ALLOW FOR MORE ACTIVE
WEATHER TO RETURN TO PARTS OF THE FORECAST AREA BY THE END OF THE
WEEKEND. A SERIES OF LOWS PROGRESSING THROUGH THE GULF WILL BRING THE
CHANCE FOR SHOWERS TO THE GULF COAST...ESPECIALLY KODIAK...WHILE A
STRONGER SYSTEM WILL BRING RAIN AND WINDS TO THE ALEUTIANS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING 111.
MARINE...GALE 130 176.
         HEAVY FREEZING SPRAY 121 129 140.
FIRE WEATHER...NONE.

MAR 11