946
FXAK68 PAFC 270057
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
457 PM AKDT MON OCT 26 2026
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3/TONIGHT
THROUGH THURSDAY)...
A DEEP LOW TRACKING INTO THE WESTERN BERING SEA IS LEADING TO
AMPLIFICATION OF THE UPPER LEVEL FLOW, WITH A RIDGE BUILDING
DOWNSTREAM OVER THE EASTERN BERING SEA AND INTO WESTERN ALASKA.
A SHORT-WAVE TROUGH OVER THE INTERIOR AND INLAND PORTIONS OF
SOUTHCENTRAL IS QUICKLY EXITING TO CANADA THIS AFTERNOON. THERE
ARE SOME LINGERING CLOUDS AND PATCHY LIGHT PRECIPITATION, MAINLY
OVER THE MOUNTAINS. HOWEVER, AS NORTHERLY (OFFSHORE FLOW)
STRENGTHENS THIS AFTERNOON AND EVENING, CLOUDS AND PRECIPITATION
WILL DIMINISH. SOME VERY WEAK COLD AIR ADVECTION COMBINED WITH
TIGHTENING PRESSURE GRADIENTS WILL PRODUCE GAP WINDS TONIGHT
THROUGH EARLY TUESDAY MORNING, MAINLY ALONG THE COAST. WINDY
LOCATIONS INCLUDE SEWARD/RESURRECTION BAY, WHITTIER/PASSAGE CANAL,
VALDEZ/THOMPSON PASS, AND THE COPPER RIVER DELTA. AS THE UPPER
RIDGE BUILDS INTO SOUTHCENTRAL OVERNIGHT THROUGH TUESDAY MORNING,
FOG WILL BE A THREAT FOR INLAND VALLEYS AND COOK INLET. WHATEVER
FOG DOES FORM COULD LINGER UNTIL TUESDAY AFTERNOON AS THE RIDGE
MOVES OVERHEAD AND WINDS BECOME LIGHT AT ALL LEVELS OF THE
ATMOSPHERE. OTHERWISE, EXPECT ABUNDANT SUNSHINE ON TUESDAY. THE
FOG WILL BE SLOW TO PROGRESS EASTWARD, SO AREAS OF FOG ARE LIKELY
AGAIN TUESDAY NIGHT INTO WEDNESDAY.
THE NEXT SIGNIFICANT CHANGE IN WEATHER WILL COME WEDNESDAY NIGHT
INTO THURSDAY AS THE RIDGE IS PUSHED EASTWARD BY A SHORT-WAVE
TROUGH AND SURFACE FRONTAL SYSTEM ARRIVING FROM THE BERING SEA.
MOST OF THE IMPACTS OF WILL BE FROM KODIAK TO THE KENAI
PENINSULA, ANCHORAGE, AND MAT-SU. THE FRONT WILL BE OCCLUDING AS
IT APPROACHES SOUTHCENTRAL AND THERE WON'T BE MUCH IN THE WAY OF
WARM AIR ADVECTION. STILL, THIS WILL BE PRIMARILY A RAIN EVENT FOR
LOWER ELEVATIONS FROM THE MAT VALLEY TO ANCHORAGE AND THE KENAI
PENINSULA. THE SUSITNA VALLEY IS THE ONE PLACE THAT WILL LIKELY
SEE SOME LIGHT SNOW ACCUMULATION. THE TROUGH AND THE FRONT WILL
QUICKLY WEAKEN AS THEY PROGRESS EASTWARD, WITH ANOTHER STRONG
STORM SYSTEM TRACKING INTO THE BERING AND CAUSING A NEW RIDGE TO
BUILD AND OVERTAKE THE SHORT-WAVE OVER SOUTHCENTRAL. THUS, DRY
CONDITIONS WILL HOLD IN LONGER FOR CORDOVA, VALDEZ, AND THE
COPPER RIVER BASIN.
STRONGER AND MORE PROGRESSIVE FLOW ALOFT WITH THIS NEXT BERING
SYSTEM WILL BRING WILL BRING A LEADING FRONTAL SYSTEM BARRELING
INTO THE WESTERN GULF AND SOUTHCENTRAL BY LATE THURSDAY. THERE IS
HIGH CONFIDENCE (70-85%) THAT THIS SYSTEM WILL BRING WIDESPREAD
HEAVY RAIN AND WIND TO KODIAK, THE GULF COASTAL WATERS, AND MUCH
OF SOUTHCENTRAL ALASKA AS WE CONTINUE THROUGH THE REMAINDER OF THE
WORK WEEK.
-SEB
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3)...
KEY MESSAGES:
* PROLONGED SOUTHERLY / SOUTHWESTERLY WINDS MAKE CONDITIONS
FAVORABLE FOR MINOR FLOODING AND EROSION ALONG THE KUSKOKWIM
DELTA COAST THROUGH WEDNESDAY MORNING.
* ANOTHER STRONG LOW PRESSURE SYSTEM ASSOCIATED WITH THE REMNANTS
OF EX-TYPHOON CHAMPI COULD BRING ELEVATED SEAS AND STRONG WINDS
TO MUCH OF THE BERING SEA AND ALEUTIANS TOWARDS THE LATTER HALF
OF THE WEEK. THIS SYSTEM WILL BRING THE THREAT FOR ADDITIONAL
COASTAL IMPACTS ALONG THE KUSKOKWIM DELTA COAST LATE THIS WEEK.
DISCUSSION:
LOW PRESSURE NEAR THE BERING STRAIT BRINGS A FRONT TO THE
SOUTHWEST MAINLAND THIS EVENING. SOUTHWEST WINDS AHEAD OF IT
THIS AFTERNOON RANGED FROM 30 TO 40 MPH; FAR LOWER THAN THEIR
PEAK OVERNIGHT. RAIN AND AREAS OF FOG WILL CONTINUE THROUGH LATE
TUESDAY EVENING. A WEAK LOW MOVES THROUGH BRISTOL BAY TOMORROW
EVENING BRINGING A QUICK BURST OF WIND GUSTS TO 40 MPH LATE
TOMORROW EVENING ALONG THE COAST FROM CAPE NEWENHAM TO MEKORYUK.
AFTERWARD, WINDS SHIFT MORE OUT OF THE SOUTH. OVERNIGHT TUESDAY
INTO LATE WEDNESDAY MORNING, WIND GUSTS ALONG THE COAST INLAND TO
BETHEL, WIND GUSTS HAVE A 40% CHANCE OF EXCEEDING 50 MPH THOUGH A
20% CHANCE OF EXCEEDING 60 MPH. RAIN SHOWERS WILL ACCOMPANY THESE
WIND GUSTS TOO WITH AMOUNTS RANGING FROM 0.15" TO 0.30".
WEDNESDAY AFTERNOON AND INTO THURSDAY MORNING, WIND GUSTS REMAIN
BELOW 40 MPH AS WEAK RIDGING MOVES OVER THE AREA. A HIGH SURF
ADVISORY THROUGH EARLY WEDNESDAY MORNING HAS BEEN ISSUED TO THIS
ONSHORE FLOW.
A STRONG LOW PRESSURE SYSTEM WILL WILL BARREL THROUGH THE WESTERN
ALEUTIANS AS EARLY AS WEDNESDAY MORNING. IT MOVES THROUGH THE
BERING SEA WEDNESDAY AFTERNOON CAUSING SOUTHERLY WINDS THROUGH
THE CENTRAL ALEUTIANS. WIND GUSTS IN THE WESTERN AND CENTRAL
ALEUTIANS FROM THIS MID-WEEK FRONT HAVE A 40% TO 80% CHANCE OF
EXCEEDING 60 MPH; GALE TO STORM FORCE STRENGTH. RAIN WILL BE THE
PRIMARY PRECIPITATION TYPE AS WINDS RAIN FROM THE SOUTH. THIS
FRONT REACHES THE EASTERN ALEUTIANS, ALASKA PENINSULA AND THE
MAINLAND THURSDAY BRINGING ONSHORE WINDS TO THE MAINLAND WITH A
60% OF GUSTS EXCEEDING 60 MPH. RAIN WILL BE THE PRIMARY
PRECIPITATION TYPE.
-JOHNSTON
LONG TERM FORECAST (DAYS 4 THROUGH 7: FRIDAY THROUGH MONDAY)
THE LONG TERM LOOKS TO REMAIN QUITE ACTIVE, PARTICULARLY FOR THE
BERING SEA, ALEUTIAN CHAIN, AND SOUTHWEST ALASKA LOCATIONS. BY
FRIDAY, THE GLOBAL MODELS ARE IN FAIRLY GOOD AGREEMENT AND DEPICT
EX-TYPHOON CHAMPI AS A LARGE, DEEP, AND OCCLUDED LOW PRESSURE
SYSTEM MOVING EASTWARD ACROSS THE BERING WITH ITS FRONT QUICKLY
ENTERING THE GULF OF ALASKA. AS THE FRONT NEARS THE GULF COAST,
EXPECT COASTAL RIDGING AND A RETURN OF GAP WINDS FOR SOUTHCENTRAL
FOR THE TURNAGAIN ARM, KNIK RIVER VALLEY, AND COPPER RIVER BASIN.
FOR THE WEST, THE BIGGEST HAZARD WITH THIS SYSTEM WILL BE WIND,
AND THE GFS HAS STORM FORCE WINDS IN THE BOUNDARY LAYER FRIDAY
AFTERNOON MOVING ACROSS THE SOUTHERN BERING AND CENTRAL ALEUTIANS
ON THE BACKSIDE OF THE SYSTEM. THE SURFACE LOW WILL BE WEAKENING
AS IT MOVES INLAND INTO SOUTHWEST ALASKA, WITH STRONG
NORTHWESTERLY GAP WINDS BECOMING A COMMON THEME FOR THE CENTRAL
AND EASTERN ALEUTIANS BY SATURDAY MORNING. PATTERN RECOGNITION
SUGGESTS THAT ONE PLACE TO WATCH WILL BE COLD BAY, AS NORTHWEST
WINDS CAN BE ESPECIALLY ENHANCED THROUGH THE GAP THERE. EXPECT GAP
WINDS ELSEWHERE TO BE ELEVATED, BUT GENERALLY DECREASING IN
INTENSITY THROUGH THE FAVORED BAYS AND PASSES OF THE ALASKA
PENINSULA THROUGH SATURDAY AFTERNOON.
MODELS SHOW (TO SOME DEGREE) A SECONDARY LOW PRESSURE SYSTEM
SITUATED OFF THE KAMCHATKA PENINSULA FOR THE WEEKEND. STILL QUITE
A BIT OF SPREAD ON THIS SYSTEM AS THE GFS REMAINS THE MUCH MORE
BULLISH/STRONGER SOLUTION WHILE OTHER MODEL GUIDANCE CONTINUES TO
STRUGGLE RESOLVING THIS SYSTEM IN TERMS OF INTENSITY AND
POSITIONING. 850 MB TEMPERATURE ANOMALIES SUGGEST THAT
TEMPERATURES STAY AT OR ABOVE AVERAGE THROUGH THE END OF THE LONG
TERM FOR THE BOTH THE WEST AND EAST.
-AM
AVIATION
PANC...GUSTY SOUTHERLY WINDS WILL CONTINUE TO DIMINISH QUICKLY
THIS AFTERNOON AND EVENING. A CLOUD DECK HOVERING BETWEEN 3000 AND
4000 FT SITUATED NORTH OF THE TERMINAL COULD BRING CEILINGS INTO
MVFR RANGE IN THE NEAR TERM AT TIMES THROUGH THE EARLY EVENING
HOURS. ASSUMING RESIDUAL CLOUD COVER BREAKS UP OVERNIGHT, THERE
WILL BE A THREAT FOR FOG AND LOW STRATUS TO DEVELOP OVERNIGHT
TONIGHT, POSSIBLY LEADING TO PROLONGED MVFR CONDITIONS OR LOWER.
ANY STRATUS COULD BE SLOW TO BREAK UP DURING THE COURSE OF THE DAY
TOMORROW, SO THERE WILL BE A DECENT (50-60%) CHANCE FOR LOW
CEILINGS TO PERSIST THROUGH THE END OF THE TAF PERIOD.
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