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FXAK68 PAFC 141324
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
524 AM AKDT TUE MAY 14 2013

.ANALYSIS AND UPPER LEVELS...
THE PATTERN THAT HAS DOMINATED MOST OF THE WEATHER IN THE STATE
RECENTLY IS FINALLY BEGINNING TO CHANGE...AS THE WEAK LOW IN THE
NORTHERN GULF DISSIPATES NEAR PRINCE WILLIAM SOUND. ANOTHER WEAK LOW
CONTINUES TO SLOWLY MOVE EAST WELL SOUTH OF SHEMYA...AND WILL PLAY A
HAND IN THE WEATHER FOR MUCH OF THE AOR THROUGH NEXT WEEKEND. AN
UPPER LEVEL TROUGH OVER THE EASTERN HALF OF THE MAINLAND IS SLOWLY
SLIDING EAST...AND WILL MOVE INTO THE YUKON TERRITORY BY TOMORROW
MORNING.

.MODEL DISCUSSION...
AS HAS BEEN THE CASE OVER THE PAST FEW DAYS...THE MODELS ARE IN GOOD
AGREEMENT SYNOPTICALLY...BUT STRUGGLE WITH PRECIPITATION OVER
SOUTHCENTRAL. THE GFS CONTINUES TO DO THE BEST IN CAPTURING THE COOK
INLET SHOWER ACTIVITY AHEAD OF THE UPPER LEVEL TROUGH.
HOWEVER...RECENT SHOWER DEVELOPMENT WEST OF HOMER INDICATES THAT THIS
SOLUTION MAY ALSO BE TOO QUICK TO BRING AN END TO THE RAINFALL FOR
THE KENAI PENINSULA. AFTER THE UPPER LEVEL TROUGH PASSES
WEDNESDAY...THE MODELS CONTINUE TO BE IN VERY GOOD AGREEMENT WITH THE
ALEUTIAN LOW AS IT MOVES INTO GULF FOR EARLY THIS WEEKEND.

.SHORT TERM FORECAST...
SOUTHCENTRAL...AS THE UPPER LEVEL TROUGH PASSES OVER SOUTHCENTRAL
TODAY...THE RAIN AND SNOW WILL END FROM WEST TO EAST. THERE IS A
CHANCE THAT ISOLATED TO SCATTERED RAIN AND SNOW SHOWERS WILL REFORM
FROM THE KENAI PENINSULA TO THE MATANUSKA VALLEY TODAY. SKIES WILL
THEN QUICKLY CLEAR THIS EVENING BEHIND THE TROUGH...AND CONTINUE
CLEARING THROUGH TOMORROW. FURTHER EAST...ACCUMULATING SNOW WILL
CONTINUE THROUGHOUT THE COPPER RIVER BASIN TODAY...WHERE A WINTER
WEATHER ADVISORY REMAINS IN EFFECT UNTIL 4PM THIS AFTERNOON.

SOUTHWEST/AKPENN...WITH THE EXCEPTION OF GUSTY NORTHERLY WINDS ALONG
THE KUSKOKWIM DELTA COAST TODAY...THE WEATHER HERE WILL REMAIN FAIRLY
BENIGN UNTIL WEDNESDAY. THIS IS WHEN THE LOW CURRENTLY SOUTH OF THE
WESTERN ALEUTIANS WILL BEGIN TO BRING RAIN TO THE ALASKA PENINSULA.
PRECIPITATION WILL THEN SPREAD INTO THE SOUTHWEST MAINLAND FOR
THURSDAY.

BERING SEA/ALEUTIANS...THE FOG THAT WAS OVER MUCH OF THE BERING SEA
AS LIFTED TO A LOW MARINE STRATUS AS THE BERING SEA RIDGE WEAKENED
OVERNIGHT. THIS STRATUS LAYER IS HOWEVER EXPECTED TO CONTINUE AT
LEAST UNTIL MID WEEK...WHEN IT WILL BEGIN TO BE BROKEN UP BY THE
ALEUTIAN LOW.

.LONG TERM FORECAST...
THERE HAS BEEN LITTLE CHANGE TO THE LONG TERM FORECAST THINKING SINCE
YESTERDAY. THEREFORE CONFIDENCE THAT UNSEASONABLY COLD AIR WILL
SETTLE INTO MAINLAND ALASKA LATE THIS WEEK AND THIS WEEKEND CONTINUES
TO INCREASE. WE ARE ALSO CONTINUING THE MONITOR THE POTENTIAL FOR A
LATE SEASON SNOWFALL FOR THE ANCHORAGE BOWL ON SATURDAY. TO GIVE A
CLIMATOLOGICAL PERSPECTIVE ON THIS...IF ACCUMULATING SNOW FELL AT
ANCHORAGE FROM THIS SYSTEM...IT WOULD ONLY BE THE 3RD TIME IN THE
CLIMATOLOGICAL RECORD BOOK THAT MEASURABLE SNOWFALL HAS FALLEN AT
ANCHORAGE IN THE 2ND HALF OF MAY. IT WOULD NOT HOWEVER BE THE LATEST
MEASURABLE SNOWFALL IN HISTORY...THAT RECORD CURRENTLY STANDS AT MAY
22ND 1964.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...WINTER WEATHER ADVISORY 141
MARINE...NONE
FIRE WEATHER...NONE

DEK MAY 13