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000
FXAK68 PAFC 212126
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
130 PM AKDT TUE MAY 21 2013

.ANALYSIS AND UPPER LEVELS...
A VERTICALLY STACKED 997 MB LOW HAS MOVED NORTHWARD THROUGH THE
BERING SEA AND IS NOW LOCATED NEAR THE PRIBILOF ISLANDS. AN
ASSOCIATED FRONT IS WEAKENING AND MAKING SLOW PROGRESS ACROSS THE
SOUTHWEST MAINLAND. GALE-FORCE WINDS ARE STILL OCCURRING FROM THE
ALASKA PENINSULA TO THE KUSKOKWIM DELTA COASTLINE. STEADY MODERATE
RAINFALL IS CONFINED TO THE ALASKA PENINSULA...WITH MORE SHOWERY
PRECIPITATION FURTHER TO THE NORTH. EAST OF THE ALASKA RANGE...MID
AND HIGH-LEVEL CLOUDS ASSOCIATED WITH THE AFOREMENTIONED FRONT ARE
SLOWLY PROGRESSING EASTWARD THROUGH THE AREA. LOWER COOK INLET AND
KODIAK ISLAND HAVE BEEN THE FIRST TO BE OVERTAKEN BY
CLOUDINESS...THOUGH LITTLE MORE THAN A FEW SPRINKLES HAVE THUS FAR
MANAGED TO REACH THE GROUND.

.MODEL DISCUSSION...
MODELS REMAIN IN EXCELLENT AGREEMENT THROUGH THE FIRST 3 DAYS OF THE
FORECAST. THE CURRENT BERING LOW WILL CONTINUE TO WEAKEN AND MAKE A
TURN BACK TO THE WEST AND DISSIPATE OVER THE NORTHERN BERING BY
THURSDAY. BY THE END OF THE WEEK...ANOTHER PACIFIC LOW MOVES
NORTHWARD TOWARD THE BERING SEA. THE MODELS CONTINUE TO STRUGGLE A
BIT WITH THE PLACEMENT OF THIS LOW...THOUGH ALL ARE IN THE SAME
BALLPARK SOUTH OF THE CENTRAL ALEUTIANS. THE NAM REPRESENTED A GREAT
MIDDLE-GROUND SOLUTION BETWEEN THE SLIGHTLY DIFFERENT
GFS/ECMWF/GEMGLB SOLUTIONS...AND WAS THE PRIMARY MODEL INCORPORATED
INTO THE FORECAST PROCESS TODAY.

.SHORT TERM FORECAST...
SOUTHCENTRAL...VISIBLE SATELLITE IMAGERY SHOWS MID-LEVEL CLOUDINESS
SPREADING NORTHWARD INTO UPPER COOK INLET THIS AFTERNOON. THESE
CLOUDS WILL CONTINUE A SLOW ADVANCE TOWARD THE NORTHEAST...REACHING
PRINCE WILLIAM SOUND AND THE SUSITNA VALLEY BY MORNING. THE FRONT
WILL BE FALLING APART SIGNIFICANTLY AS IT MOVES INTO THE AREA...THUS
PRECIP ON WEDNESDAY WILL BE FAIRLY MINIMAL AND CONFINED LARGELY TO
THE COAST. A FEW SHOWERS MAY MAKE IT INTO THE INLAND AREAS...BUT THE
MAIN IMPACT TO ANCHORAGE AND THE MAT-SU VALLEY WILL BE CLOUDINESS.
SEA BREEZES SEEN TODAY ACROSS COOK INLET AND PRINCE WILLIAM SOUND
WILL LIKELY BE GREATLY DIMINISHED TOMORROW DUE TO THE CLOUDS THAT
WILL INHIBIT HEATING. AFTERNOON HIGH TEMPERATURES TOMORROW WILL BE
SIMILAR TO TODAY...THOUGH BY THURSDAY SKIES WILL CLEAR AND
TEMPERATURES SHOULD JUMP TO NEAR-NORMAL AT MOST AREAS.

SOUTHWEST...WINDS AND RAIN WILL GRADUALLY DIMINISH THROUGH
TONIGHT...WITH ONSHORE FLOW AND SHOWERS PERSISTING THROUGH WEDNESDAY
AFTERNOON. A SHORTWAVE RIDGE WILL MOVE IN FROM THE SOUTH ON THURSDAY
AND FRIDAY...CLEARING SKIES AND ALLOWING TEMPERATURES TO REBOUND
DRAMATICALLY TO NEAR-NORMAL VALUES.

BERING SEA AND ALEUTIANS...UNSETTLED WEATHER TO CONTINUE THROUGH THE
WEEKEND IN THE FORM OF TWO DIFFERENT STORM SYSTEMS. THE FIRST AND
PRESENT STORM WILL DRIFT NORTHWEST AND WEAKEN THROUGH TOMORROW
AFTERNOON...KEEPING SCATTERED RAIN SHOWERS ACROSS MUCH OF THE BERING
SEA. THE EASTERN ALEUTIANS WILL SEE MUCH-IMPROVED CONDITIONS ON
THURSDAY AS THE AFOREMENTIONED SHORTWAVE RIDGE MOVES INTO THE AREA
AND CLEARS OUT MID-LEVEL CLOUDS. THE SECOND STORM APPROACHES THE
CENTRAL ALEUTIANS FRIDAY MORNING WITH GUSTY WINDS AND RAIN...THOUGH
AT THIS TIME THE ASSOCIATED WEATHER FRONT LOOKS LIKE IT WILL BE
WEAKER THAN THE FRONT THAT HAS AFFECTED THE REGION FOR THE LAST 48
HOURS.

.LONG TERM FORECAST...
LONG-RANGE MODELS REMAIN IN FAIRLY GOOD AGREEMENT THAT ACTIVE WEATHER
WILL REMAIN OVER THE BERING SEA THROUGH THE WEEKEND AND THEN SHIFT
EASTWARD INTO THE FAR SOUTHERN GULF. BOTH OF THESE PATTERNS WILL
ALLOW HIGHER PRESSURE AND WARMING TEMPERATURES TO MOVE INTO THE
INTERIOR PORTIONS OF THE STATE FROM NORTHWEST CANADA. EXPECT
TEMPERATURES TO FINALLY BOUNCE BACK TO NEAR-NORMAL AT MANY
AREAS...WITH MAIN WEATHER THREAT TRANSITIONING INTO CONVECTIVE
AFTERNOON/EVENING SHOWERS AT MANY LOCATIONS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...FLOOD WATCH 152
MARINE...NONE
FIRE WEATHER...NONE

DIXON MAY 13