745
FXAK68 PAFC 211209
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
409 AM AKDT WED OCT 21 2026
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
DISCUSSION:
A LARGE UPPER-LEVEL LOW CONTINUES TO SLOWLY DRIFT SOUTHEAST FROM
COOK INLET OVERNIGHT OFF THE SOUTHEAST COAST OF THE KENAI
PENINSULA THIS MORNING. ALTHOUGH THIS SYSTEM IS WEAKENING,
MULTIPLE VORTICITY LOBES ROTATING AROUND THE LOW IS ALLOWING FOR
SOME ENHANCEMENT OF LIGHT MIXED PRECIPITATION FROM THE WESTERN
COPPER RIVER BASIN TO THE MAT-SU VALLEYS AND ANCHORAGE BOWL.
SOUTH AND EAST OF THE LOW, THE PRECIPITATION IS MORE SHOWERY IN
NATURE DUE TO A CONTINUED INTRUSION OF COLDER AIR ALOFT.
THE HEAVIEST PRECIPITATION THIS MORNING IS OVER PRINCE WILLIAM
SOUND TO CORDOVA AND NORTH ALONG THE COASTAL MOUNTAINS. BANDS OF
HEAVY SNOW SHOWERS WILL PERSIST FROM KEYSTONE CANYON AND THOMPSON
PASS TO THE KENNY LAKE AREA THROUGH THIS AFTERNOON, TAPERING OFF
AS THE UPPER-LEVEL LOW AND A DEVELOPING SURFACE LOW SOUTH OF
SEWARD BOTH MOVE SOUTHEAST OVER THE CENTRAL GULF OF ALASKA.
THE NORTH-NORTHEASTERLY FLOW OVER INTERIOR SOUTHCENTRAL WILL ALSO
ALLOW FOR SOME AREA OF LIGHT SNOW TO CONTINUE FROM PAXSON TO
EUREKA THROUGH THIS EVENING, WITH UPSLOPE AREAS, SUCH AS THOSE
AROUND EUREKA, LIKELY TO SEE ANOTHER ONE TO TWO INCHES OF SNOW
TODAY.
AS THE SNOW TAPERS OFF AND THE AFOREMENTIONED SURFACE LOW MOVES
SOUTH IN TANDEM WITH A STRONG RIDGE OF HIGH PRESSURE BUILDING OVER
THE INTERIOR, THE PRESSURE GRADIENT BETWEEN THE TWO WILL ALLOW
GUSTY GAP WINDS TO PERSIST THROUGH RESURRECTION BAY, PASSAGE
CANAL, AND BAYS AND PASSES AROUND EASTERN PRINCE WILLIAM SOUND
THROUGH THURSDAY.
OVERNIGHT LOWS ACROSS THE BULK OF SOUTHCENTRAL WILL BE MUCH
COLDER OVER THE NEXT FEW DAYS, DIPPING INTO THE TEENS AND 20S IN
MOST SPOTS FOR THURSDAY MORNING, AND INTO THE SINGLE DIGITS FOR
PORTIONS OF THE COPPER RIVER VALLEY IF SKIES REMAIN CLEAR. LOW
TEMPERATURES OVERNIGHT THURSDAY INTO FRIDAY MORNING WILL LIKELY
BE EVEN COLDER, WITH WIDESPREAD TEENS FOR LOCATIONS AWAY FROM THE
IMMEDIATE COAST AND SINGLE DIGITS TO NEAR ZERO DEGREES FOR
LOCATIONS IN THE COPPER RIVER BASIN.
FOG MAY FORM ACROSS ANCHORAGE, THE MAT-SU, AND THE KENAI
PENINSULA DUE TO MOIST GROUND AND CLEARING SKIES. COOL AND DRY
CONDITIONS PERSIST THROUGH FRIDAY AS AN UPPER RIDGE ENCROACHES
INTO SOUTHCENTRAL FROM THE WEST. LOOKING AHEAD, A FRONT LOOKS TO
MOVE INTO SOUTHCENTRAL FROM THE WEST ON SATURDAY, LIKELY BRINGING
RAINFALL TO KODIAK ISLAND. SOUTHERLY FLOW WITH THIS FRONT MAY
BRING WARMER TEMPERATURES ALONG WITH IT, WARMING EVEN INLAND
TEMPERATURES TO THE 40S.
-TM/JAR
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3)...
KEY MESSAGES:
* A HIGH WIND WATCH FOR COLD BAY AND KING COVE FROM FRIDAY
MORNING TO SATURDAY MORNING WITH SOUTHEAST WINDS POTENTIALLY
GUSTING UP TO 75 MPH.
* A HIGH WIND WATCH FOR THE KUSKOKWIM DELTA/COAST, BRISTOL BAY
COAST, AND PLATINUM TO GOODNEWS BAY FROM FRIDAY MORNING TO
SATURDAY MORNING. SOUTH WINDS COULD GUST AS HIGH AS 70 MPH, AND
THERE IS MEDIUM TO HIGH CONFIDENCE (60 TO 80 PERCENT) IN WIND
GUSTS EXCEEDING 60 MPH.
* A COASTAL FLOOD WATCH FOR THE KUSKOKWIM DELTA COAST, INCLUDING
KIPNUK AND KWIGILLINGOK FROM 8AM FRIDAY THROUGH 1AM SATURDAY,
PARTICULARLY AROUND HIGH TIDES NEAR 10AM AND 10PM FRIDAY. THE
MOST LIKELY SCENARIO IS FOR WATER LEVELS TO BE 2 TO 3 FEET ABOVE
THE NORMAL HIGHEST TIDE LINE.
DISCUSSION:
A STORM FORCE FRONT EXTENDING OFF A ~960 MB KAMCHATKA LOW ENTERS
THE WESTERN BERING LATE THIS AFTERNOON AND WILL WORKS ITS WAY EAST
TOWARDS THE SOUTHWEST COAST THROUGH THE END OF THE WEEK.
THE CORE OF STORM FORCE WINDS ALONG THE FRONT WILL BE ACCOMPANIED
BY WIDESPREAD HIGH END GALE FORCE WINDS WILL SPREAD ACROSS THE
BERING SEA AND ALEUTIAN CHAIN TONIGHT THROUGH THURSDAY AFTERNOON BEFORE
REACHING THE SOUTHWEST COAST. SOUTHERLY WIND DIRECTIONS ALONG THE
SOUTHERN ALASKA PENINSULA WILL PROMPT FUNNELING THROUGH KING COVE
AND COLD BAY. WIND GUSTS REACHING OR EXCEEDING 75 MPH IS POSSIBLE
(40-60% CHANCE). SOUTH TO SOUTHWESTERLY GALE FORCE WINDS WILL PUSH
ALONG THE COAST AND THEN FORCE THEIR WAY INLAND LATE THURSDAY
NIGHT INTO FRIDAY MORNING, SPENDING MUCH OF FRIDAY WORKING ACROSS
THE MAINLAND. WIND GUSTS TO 60MPH OR HIGHER ARE LIKELY (70-80%
CHANCE) ALONG THE COAST AND AS FAR INLAND AS BETHEL. PERSISTENT
GUSTY SOUTH/SOUTHWESTERLY WINDS AND SURGE MAY PROMOTE COASTAL
IMPACTS, ESPECIALLY ALONG THE KUSKOKWIM DELTA COAST, HOWEVER, THE
NORTHERN BRISTOL BAY COAST MAY SEE AREAS OF HIGHER SURF AS WELL.
MODERATE RAINFALL ASSOCIATED WITH THE FRONT WILL MOST LIKELY
COMPOUND COASTAL IMPACTS.
KM/AM
.LONG TERM FORECAST (DAYS 4 THROUGH 7: SATURDAY THROUGH
TUESDAY)...
KEY MESSAGES:
* A SERIES OF STRONG STORMS MOVE ACROSS THE BERING SEA AND INTO
ALASKA FROM FRIDAY THROUGH THE WEEKEND, BRINGING STRONG WINDS
AND HEAVY PRECIPITATION.
* CONFIDENCE IS LOW TO MEDIUM WITH REGARDS TO IMPACTS, STRONG
ONSHORE WINDS AND ELEVATED COASTAL WATER LEVELS CONCERNS FOR
SOUTHWEST ALASKA, MAINLY FRIDAY AND SATURDAY AND AGAIN ON
MONDAY.
DISCUSSION:
THE BIGGEST STORY IN THE LONG-TERM FORECAST CONTINUES TO FOCUS ON
A STRONG LOW TRANSITING FROM THE KAMCHATKA PENINSULA TO ALASKA.
ENSEMBLES CONTINUE TO BE IN RELATIVELY GOOD AGREEMENT WITH THIS
STORM, WITH SEEMINGLY HIGHER-THAN-AVERAGE FORECAST CONFIDENCE
GIVEN THAT THIS FEATURE IS 3 TO 6 DAYS OUT. GOOD RUN-TO-RUN
CONSISTENCY AMONG DETERMINISTIC GLOBAL MODELS IS ALSO CONTRIBUTING
TO HIGHER-THAN-AVERAGE FORECAST CONFIDENCE. THE AREAS OF HIGHEST
AGREEMENT WITH THIS FEATURE ARE FOR GALE TO STORM FORCE SUSTAINED
WINDS ALONG THE FRONT AS IT MOVES ACROSS THE ALEUTIAN CHAIN, THE
SOUTHWEST ALASKA COASTLINE, AND THE ALASKA PENINSULA. THESE
ONSHORE WINDS ARE RAISING CONCERNS FOR COASTAL IMPACTS (INCLUDING
HIGH SURF AND PERHAPS EVEN MINOR COASTAL FLOODING) FOR SOUTH-
FACING PORTIONS OF THE WESTERN COAST. A HIGH WIND WATCH HAS BEEN
ISSUED FOR PORTIONS OF THE SOUTHWEST COAST AND FOR THE COLD BAY
AREA AS THE FRONT PASSES. WE ARE CLOSELY MONITORING THIS STORM AS
IT TRANSITIONS FROM THE LONG TERM FORECAST TO THE SHORT TERM.
SOUTHCENTRAL SHOULD BE SPARED THE WORST OF THE WINDS WITH THIS
STORM, AS THE FRONT WILL VERY LIKELY BE WEAKENING BY THE TIME IT
EXITS SOUTHWEST ALASKA.
IN ADDITION TO WINDS, THERE WILL ALSO BE PLENTY OF MOISTURE ALONG
THE FRONT, WHICH WILL BRING PERIODS OF MODERATE TO HEAVY
PRECIPITATION TO THE ALEUTIANS, ALASKA PENINSULA, AND SOUTHWEST
ALASKA. GIVEN THE STRONG WINDS ASSOCIATED WITH THE FRONT,
PRECIPITATION TOTALS WILL DEPEND ON NOT ON THE DURATION OF THE
FRONT OVER THE AREA, BUT ALSO ITS INTERACTION WITH TERRAIN
FEATURES INCLUDING OROGRAPHIC LIFT AND AREAS OF DOWNSLOPING THAT
WOULD REDUCE PRECIPITATION TOTALS. WHILE WARM AIR ADVECTION WILL
LIKELY KEEP PRECIPITATION MOSTLY RAIN FOR THE MAJORITY OF
SOUTHWEST ALASKA, COLDER AIR LINGERING IN SOUTHCENTRAL COULD MEAN
THAT LOWER ELEVATION AREAS MAY SEE SNOW.
AFTER THIS BERING LOW MOVES NORTH AND THE FRONT WEAKENS,
SOUTHWESTERLY FLOW DOMINATES THE BERING SEA WITH EMBEDDED SURFACE
LOWS THAT WILL CONTINUE TO KEEP WEATHER ACTIVE WITH AT LEAST
PERIODS OF GALE FORCE WINDS ACROSS THE BERING. HOWEVER, RESOLVING
THESE FEATURES ARE LESS CLEAR THROUGH EARLY NEXT WEEK.
THE FRONT COULD CONTINUE INTO SOUTHCENTRAL, BRINGING
PRECIPITATION TO THE REGION THIS WEEKEND. LOW CONFIDENCE ON THE
FORECAST AMOUNTS AS MODELS VARY WITH ITS PROGRESSION EASTWARD.
OTHERWISE HIGH PRESSURE BEGINS TO BUILDS ACROSS THE AREA SUNDAY
UNTIL MIDWEEK.
AVIATION
PANC...PREDOMINANTLY VFR CONDITIONS AND NORTHERLY WINDS UP TO 10
KT PERSIST THROUGH TODAY. A 20 TO 30 PERCENT CHANCE OF SHOWERS
LINGERS THROUGH MIDMORNING, WHICH MAY ALLOW FOR BRIEF PERIODS OF
MVFR CEILINGS AS SHOWERS MOVE THROUGH. SHOWER CHANCES DIMINISH BY
LATE THIS MORNING.
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