Small Craft Advisory 293, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKDT TUE APR 2 2013

.MODEL DISCUSSION...
THE GLOBAL MODELS ARE IN VERY GOOD AGREEMENT THROUGH 84 HOURS. THE
NAM (NOT A GLOBAL MODEL) STARTS TO DIVERGE FROM THE OTHER GUIDANCE
BY 36 HOURS AND AFTER THAT POINT IT IS NOT AS RELIABLE. CONFIDENCE
FOR THIS FORECAST PACKAGE IS HIGHER THAN NORMAL.

.ANALYSIS AND UPPER LEVELS...
THERE IS A LARGE UPPER LEVEL LOW CENTERED JUST SOUTH OF THE ALEUTIAN
ISLANDS. THERE IS A RIDGE OVER WESTERN ALASKA AND ANOTHER ONE OVER
THE EASTERN GULF OF ALASKA. AN UPPER LEVEL LOW IS OVER NORTHWEST
CANADA WITH A TROUGH STRETCHING INTO NORTHEAST ALASKA. THIS LEAVES
THE AREA FROM SOUTH CENTRAL ALASKA TO THE UPPER ALASKA PENINSULA
(EAST OF CHIGNIK) IN A "COL" BETWEEN THE TWO MAIN HIGHS AND THE TWO
MAIN LOWS. A WEAK UPPER LOW SOUTH OF THE ALASKA PENINSULA IS MOVING
NORTHEAST TOWARDS THE COL.

.SHORT TERM FORECAST...
FOR SOUTH CENTRAL ALASKA...THE PENINSULA LOW WILL "SCOOT" THROUGH THE

COL TONIGHT...MOVING INLAND OVER THE NORTHERN PANHANDLE EARLY
WEDNESDAY AFTERNOON. THIS WILL BRING SLIGHT CHANCES OF PRECIPITATION
TO COASTAL AREAS BUT LEAVE INLAND AREAS DRY. BEGINNING WEDNESDAY
AFTERNOON THE EASTERN GULF RIDGE WILL PUSH INTO THE NORTHERN GULF
AND REMAIN THERE INTO FRIDAY. AT THE SAME TIME THE CANADIAN LOW WILL
SLOWLY MOVE WEST WITH THE CENTER OF THE LOW MOVING INTO NORTHEAST
ALASKA ON FRIDAY. THE RESULT OF THIS WILL BE DRY WEATHER FOR SOUTH
CENTRAL ALASKA AND THE GULF COAST WITH THE EXCEPTION OF KODIAK
ISLAND...WHICH WILL SEE ONSHORE FLOW FROM THE ALEUTIAN LOW. IN
ADDITION THE INTRODUCTION OF COLDER AIR IN INTERIOR ALASKA WILL
INCREASE THE OFFSHORE FLOW AND THUS GAP FLOW WINDS.

FOR SOUTHWEST ALASKA...A RIDGE OF HIGH PRESSURE WILL HOLD OVER THE
AREA THROUGH FRIDAY KEEPING CONDITIONS DRY. WEATHER FRONTS WILL
PERIODICALLY NEAR THE COAST...BUT OCCASIONAL CLOUDINESS WILL BE THE
MAIN RESULT.

FOR THE ALEUTIANS AND BERING SEA...THE MAIN WEATHER PRODUCER THROUGH
THURSDAY WILL BE THE LOW SOUTH OF THE ALEUTIANS...AND THEN LATER
THURSDAY THROUGH FRIDAY A TRIPLE POINT LOW THAT FORMS TO THE EAST OF
THAT LOW WILL BECOME THE DOMINANT LOW. THE MAIN FRONTAL BOUNDARY
WILL MOVE NORTH AND WEST INTO THE PRIBILOFS AND ALASKA PENINSULA
TONIGHT BUT STALL JUST SHY OF THE SOUTHWEST COAST OF ALASKA
WEDNESDAY AFTERNOON.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING 132 138 150 155 165 170 171 172 175 176 179.
FIRE WEATHER...NONE.

LUDWIG APR 13