Small Craft Advisory 680, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKDT FRI SEP 6 2013

.ANALYSIS AND UPPER LEVELS...
THERE IS AN UPPER LEVEL TROUGH ALONG THE WEST COAST OF ALASKA
STRETCHING SOUTH INTO THE NORTHERN PACIFIC. A NICELY WOUND UP LOW IS
CENTERED OVER KODIAK ISLAND AND MOVING NORTH. ANOTHER LOW IS
DEVELOPING ALONG THE SOUTHERN END OF THE TROUGH NEAR 45 DEGREES
NORTH LATITUDE 160 DEGREES WEST LONGITUDE. AN EASTWARD MOVING LOW IS
OVER THE WESTERN ALEUTIANS. THERE IS A RIDGE OVER THE CENTRAL BERING
SEA AND CENTRAL ALEUTIANS BETWEEN THE WEST COAST TROUGH AND THE
WESTERN BERING LOW.

.MODEL DISCUSSION...
THE NUMERICAL MODELS ARE IN GOOD AGREEMENT THROUGH 84 HOURS. THEY
STILL DIFFER A LITTLE ON THE EXACT TIMING/LOCATION OF THE KODIAK LOW
AS IT MOVES INLAND. THEY ALSO ARE STRUGGLING A LITTLE WITH THE NEXT
GULF LOW THAT ENTERS THE GULF COAST ON SUNDAY MORNING...CENTERED
SOMEWHERE BETWEEN CORDOVA AND YAKUTAT...DEPENDING ON WHICH MODEL IS
CHOSEN. THIS LEADS TO FORECAST CONFIDENCE NEAR NORMAL FOR SOUTH
CENTRAL ALASKA AND ABOVE FOR SOUTHWEST ALASKA THROUGH THE WESTERN
ALEUTIANS.

.SHORT TERM FORECAST...
FOR SOUTH CENTRAL AND SOUTHWEST ALASKA...THE KODIAK LOW WILL MOVE
INLAND TONIGHT AND BEGIN TO FALL APART. SIGNIFICANT PRECIPITATION
WILL CONTINUE ALONG THE GULF COAST THIS EVENING...MAINLY ON THE
NORTHERN AND EASTERN SIDES OF PRINCE WILLIAM SOUND. WINDS WILL ALSO
DIMINISH ACROSS THE AREA OVERNIGHT AS THE LOW WEAKENS AT ALL LEVELS.
SHOWERS ARE EXPECTED ON SATURDAY AS THE MOIST REMNANTS OF THE LOW
REMAIN OVER THE AREA. ONLY THE KUSKOKWIM DELTA REGION LOOKS TO AVOID
THE PRECIPITATION ALL TOGETHER.

THE DEVELOPING LOW ALONG THE SOUTHERN END OF THE WEST COAST TROUGH
WILL MOVE NORTHEAST AND REACH THE GULF COAST SATURDAY NIGHT AND
SUNDAY. MOST OF THE PRECIPITATION WITH THIS SYSTEM WILL BE EAST OF
THE KENAI PENINSULA...WITH JUST SOME SCATTERED SHOWERS EAST OF THAT
AS THE ASSOCIATED UPPER SHORT-WAVE LOW CROSSES SOUTHERN ALASKA. WITH
A WEAK SURFACE LOW...STRONG WINDS ARE NOT EXPECTED WITH THIS SYSTEM.

THE NEXT SYSTEM WILL REACH SOUTHERN ALASKA ON SUNDAY NIGHT AND
MONDAY. THIS SYSTEM IS ASSOCIATED WITH THE LOW THAT CROSSED THE
ALEUTIANS THE PREVIOUS COUPLE OF DAYS (SEE BELOW).

FOR THE BERING SEA AND ALEUTIANS...THE SYSTEM OVER THE WESTERN
ALEUTIANS WILL MOVE EAST ACROSS THE ALEUTIANS THROUGH SATURDAY
NIGHT...MOVING INTO THE CENTRAL ALEUTIANS LATE TONIGHT AND SATURDAY
AND INTO THE EASTERN ALEUTIANS SATURDAY NIGHT. THE RESPONSIBLE UPPER
LOW WILL SLIDE EAST JUST SOUTH OF THE ALEUTIANS THROUGH SATURDAY
NIGHT AND THEN TAKE A TURN TOWARD THE NORTHEAST ON SUNDAY...SETTLING
IN OVER THE ALASKA PENINSULA SUNDAY NIGHT AND MONDAY. THE BERING
UPPER HIGH WILL "PINCH OFF" IN THE BERING SEA TO THE NORTH OF THE
ALEUTIAN LOW...PROTECTING THE BERING SEA FROM MOST OF THE ACTION
(WINDS AND PRECIPITATION).

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING 120 125 130 132 150 170 172 175 176.
FIRE WEATHER...NONE.

LUDWIG SEP 13