900
FXAK68 PAFC 221421
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
621 AM AKDT TUE SEP 22 2026
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
KEY MESSAGES:
- ISOLATED MARINE LIGHTNING OVER THE GULF OF ALASKA IS POSSIBLE
TUESDAY AND WEDNESDAY.
- CLEARING SKIES AND COOL TEMPERATURES COULD LEAD TO PATCHY FOG,
AND WIDESPREAD LOWS NEAR OR BELOW FREEZING. BREEZY NORTH WINDS
THROUGH TERRAIN GAPS WILL INCREASE TONIGHT THROUGH WEDNESDAY
MORNING.
- THE PATTERN SHIFTS THURSDAY AND FRIDAY WITH RAIN ALONG THE COAST
AND KODIAK ISLAND. STRONG, SOUTHEAST WINDS ALSO RETURN TO
SOUTHCENTRAL. FORECAST CONFIDENCE IS MEDIUM OVERALL, BUT THE
MAGNITUDE IN RAINFALL AND WIND SPEED IS LOW TO MEDIUM.
DISCUSSION:
DUAL LOWS ACROSS THE GULF OF ALASKA ARE BRINGING SHOWERS FROM
EAST TO WEST THIS MORNING. ONE LOW IS LOCATED WEST OF THE SE
PANHANDLE WHILE THE OTHER, WEAKER LOW IS SITUATED EAST OF KODIAK
ISLAND. HIGH CLOUDS ON SATELLITE HAS OBSCURED THE LOCATIONS THAT
OBSERVED PATCHY FOG. MANY AREAS DIPPED INTO THE 30S THIS MORNING.
A FEW LIGHTNING STRIKES WERE OBSERVED FROM THESE LOWS LAST NIGHT
AND A LIGHTNING STRIKE OR TWO OVER OPEN WATERS OF THE GULF CANNOT
BE RULED OUT THROUGH WEDNESDAY.
OTHERWISE, THE WEATHER ACROSS SOUTHCENTRAL WILL BE RELATIVELY
QUIET THROUGH THURSDAY AFTERNOON AS THE LOWS WEAKEN AND SLOWLY
MEANDER EAST. ANY LINGERING SHOWERS WOULD BE LIKELY ALONG THE
ALASKA RANGE, KODIAK, AND THE NORTHERN GULF COAST THIS MORNING,
TRENDING DRIER THROUGHOUT THE DAY TODAY. CLOUDS WILL CONTINUE TO
CLEAR OUT ACROSS MUCH OF SOUTHCENTRAL THROUGH WEDNESDAY. THIS WILL
RESULT IN COLDER OVERNIGHT TEMPERATURES, WITH WIDESPREAD 20S
POSSIBLE FOR THE COPPER RIVER BASIN AND LOW TO MID 30S ELSEWHERE.
SOME TYPICALLY COLDER LOCATIONS MAY SEE COLDER TEMPERATURES
WEDNESDAY MORNING AS EAST ANCHORAGE, SOLDOTNA, BUTTE, AND WILLOW
MAY DROP AS LOW AS THE UPPER 20S AND SOME LOWS IN THE TEENS ARE
POSSIBLE (10 TO 20 PERCENT CHANCE) IN THE COPPER RIVER BASIN.
OFFSHORE WINDS LOOK TO INCREASE LATER NIGHT THROUGH NORTH TO SOUTH
TERRAIN GAPS THROUGH WEDNESDAY MORNING. WEDNESDAY AND THURSDAY
MORNING WILL SEE DRY CONDITIONS ACROSS SOUTHCENTRAL WITH HIGH
TEMPERATURES IN THE LOW TO MID 50S.
A MUCH MORE POTENT SYSTEM FROM THE BERING SEA WILL SEND A STRONG
FRONT INTO THE SOUTHWESTERN GULF AND KODIAK ISLAND BY THURSDAY
AFTERNOON. CONFIDENCE IS STILL MEDIUM WITH THE TIMING OF THE FRONT
AS MODELS SLIGHTLY DIFFER ON PROGRESSION AND STRENGTH. CHANCES
FOR PRECIPITATION WILL INCREASE THROUGHOUT THE DAY THURSDAY FOR
PRINCE WILLIAM SOUND, NORTHERN GULF COAST, AND FOR KODIAK ISLAND,
BECOMING LIKELY (MODERATE TO HEAVY RAINFALL RATES AT TIMES) BY
THURSDAY EVENING. WITH STRONG SOUTHEAST FLOW, NORTHERN COOK INLET
COMMUNITIES AND FARTHER INLAND, WOULD BECOME DOWNSLOPED, THUS
DRIER. GALE-FORCE WINDS WILL ALSO ACCOMPANY THE FRONT AS IT LIFTS
THROUGH THE GULF THURSDAY AND FRIDAY. WINDS COULD BE GUSTY THROUGH
TURNAGAIN ARM FRIDAY AFTERNOON, AFFECTING SOUTH ANCHORAGE AND THE
HILLSIDE, BUT THERE IS LOW CONFIDENCE IN THE MAGNITUDE OF THESE
WINDS AT THIS TIME. STAY TUNED.
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(DAYS 1 THROUGH 3: TODAY THROUGH THURSDAY)...
KEY MESSAGES:
* A STRONG BERING SEA LOW IS FORECAST TO IMPACT THE BERING SEA,
ALEUTIAN AND PRIBILOF ISLANDS, AND SOUTHWEST ALASKA BEGINNING
WEDNESDAY AFTERNOON INTO THIS WEEKEND.
* FOR THE BERING SEA: AREAS OF GALE FORCE WINDS WITH STORM FORCE
GUSTS LIKELY. GUSTS TO HURRICANE FORCE POSSIBLE. EXPECT ELEVATED
WAVE HEIGHTS, WITH SEAS UP TO 25 TO 35 FT POSSIBLE. HIGH SURF
POSSIBLE FOR PRIBILOF ISLANDS.
* FOR SOUTHWEST ALASKA: SOUTHEASTERLY GALE FORCE WINDS
INCREASINGLY LIKELY (80-90% CHANCE). LOCALIZED HIGH SURF AND
COASTAL FLOODING POSSIBLE, WITH PRIMARY COMMUNITIES OF CONCERN
BEING KWIGILLINGOK AND KONGIGANAK, AND COMMUNITIES NEAR AND
ALONG THE MOUTH OF THE KUSKOKWIM RIVER.
DISCUSSION:
THE PERSISTENT GUSTY NORTHWESTERLY WINDS AND SHOWERS ACROSS THE
EASTERN BERING AND ALASKA PENINSULA WILL CONTINUE TO WIND DOWN
THROUGH THIS MORNING AS RIDGING OVER THE CENTRAL BERING SLIDES
INTO THE EASTERN BERING. RIDGING REMAINS IN PLACE OVER THE EASTERN
BERING AND SOUTHWEST ALASKA OVER THE NEXT COUPLE OF DAYS,
PROMOTING A PERIOD OF QUIET WEATHER FOR TODAY INTO WEDNESDAY. THE
COLDER AIRMASS OVER SOUTHWEST ALASKA ALSO LINGERS THROUGH
WEDNESDAY NIGHT, RESULTING IN NIGHTTIME AND MORNING TEMPERATURES
TO AGAIN FALL INTO THE LOW TO MID 30S ACROSS MUCH OF SOUTHWEST
ALASKA AND UPPER 20S FOR INTERIOR LOCATIONS THROUGH WEDNESDAY
NIGHT.
OUT WEST, A STRENGTHENING LOW PRESSURE SYSTEM THAT HAS DEVELOPED
JUST TO THE SOUTH OF THE KAMCHATKA PENINSULA REACHES THE FAR
WESTERN ALEUTIAN ISLANDS THIS MORNING. THE STRONGEST WINDS AND
HEAVIEST PRECIPITATION ALONG ITS FRONTAL SYSTEM CONTINUES TO
REMAIN TO THE SOUTH OF THE ALEUTIAN CHAIN, ALTHOUGH SOME LIGHT
RAINFALL AND SMALL CRAFT WINDS ARE EXPECTED TO PROGRESS FROM WEST
TO EAST ACROSS SHEMYA THROUGH EARLY THIS MORNING AND ACROSS ADAK
AND ATKA THROUGH THIS AFTERNOON.
FOLLOWING CLOSELY BEHIND THIS LOW PRESSURE SYSTEM ARE THE
REMNANTS OF TYPHOON DUJUAN CURVING NORTHEAST ACROSS THE NORTH
PACIFIC TOWARDS THE ALEUTIAN CHAIN BY WEDNESDAY MORNING. WHILE THE
REMNANTS OF TYPHOON DUJUAN REMAIN WELL TO THE SOUTH OF THE
ALEUTIANS, THE INTERACTION BETWEEN THE TWO SYSTEMS FROM WEDNESDAY
THROUGH THURSDAY CONTINUES TO BE THE MAIN FOCUS AND CHALLENGE OF
THE FORECAST AS WARM, TROPICAL AIR AND MOISTURE WILL AID IN THE
STRENGTHENING OF THE BERING SEA LOW. OVERALL FORECAST CONFIDENCE
CONTINUES TO INCREASE AS MODEL GUIDANCE CONVERGES ON A SOLUTION OF
A STRONG LOW REACHING PEAK STRENGTH (955 TO 965 MB MINIMUM
CENTRAL PRESSURE) IN THE MIDDLE OF THE CENTRAL BERING SEA SOMETIME
BETWEEN WEDNESDAY NIGHT AND THURSDAY MORNING. DESPITE THE
REMAINING UNCERTAINTY ON THE EXACT LOCATION AND TRACK OF THE LOW
CENTER, AGREEMENT HAS SIGNIFICANTLY IMPROVED ON THE OVERALL
STRENGTH AND EXTENT OF THE WIND FIELD ACROSS THE BERING, AS WELL
AS THE FRONTAL SYSTEM SET TO SWEEP ACROSS THE SOUTHWEST ALASKA
COAST.
BY WEDNESDAY MORNING, SMALL CRAFT WINDS BECOME MUCH MORE
WIDESPREAD ACROSS THE BERING AS THE FRONTAL SYSTEM QUICKLY
STRENGTHENS AND TRACKS EAST. AS THE LOW TRACKS INTO THE CENTRAL
BERING BY WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING, SUSTAINED
GALE-FORCE WINDS ARE LIKELY TO ENCOMPASS MUCH OF THE BERING SEA
AND ALEUTIANS, WITH THE POTENTIAL (50-60% CHANCE) FOR SUSTAINED
STORM- FORCE WINDS ALONG THE ALEUTIAN CHAIN FROM THE RAT ISLANDS
TO ADAK AND ATKA THROUGH THURSDAY. WIDESPREAD GUSTS TO STORM-
FORCE AND POTENTIALLY HURRICANE FORCE (>=75 MPH) WILL BE LIKELY
ACROSS THE BERING SEA, ALEUTIANS, AND PRIBILOF ISLANDS. THE
COMBINATION OF STRONG WINDS AND LONG FETCH COULD LEAD TO HIGH
SEAS, PERHAPS ON THE ORDER OF 25 TO 35 FT ACROSS THE BERING SEA
AND NORTH PACIFIC WATERS JUST SOUTH OF THE ALEUTIANS, AS WELL AS
THE POTENTIAL FOR HIGH SURF FOR THE PRIBILOF ISLANDS.
FOR SOUTHWEST ALASKA, THERE IS HIGH CONFIDENCE FOR A GALE-FORCE
FRONT REACHING THE COAST WEDNESDAY NIGHT THROUGH THURSDAY MORNING.
STRONG SOUTHEASTERLY WINDS INCREASE WITH THE ARRIVAL OF THE FRONT
WITH THE POTENTIAL FOR GUSTS UP TO 45-55 MPH ALONG THE IMMEDIATE
COAST THROUGH THURSDAY EVENING AS THE FRONT MOVES INLAND. GIVEN
THE EAST-SOUTHEASTERLY COMPONENT TO THE WIND FIELD ALONG THE COAST
AND THE DECREASING ASTRONOMICAL TIDES, THE FORECAST HAS TRENDED
TOWARDS A LOWER POTENTIAL FOR WIDESPREAD COASTAL FLOODING ALONG
THE KUSKOKWIM DELTA COAST (20-30% CHANCE). MINOR COASTAL FLOODING
AND HIGH SURF WILL CERTAINLY STILL BE POSSIBLE, ESPECIALLY FOR
COMMUNITIES MORE SUSCEPTIBLE TO SOUTHEAST WINDS SUCH AS
KWIGILLINGOK, KONGIGANAK, AND COMMUNITIES NEAR OR ALONG THE MOUTH
OF THE KUSKOKWIM RIVER. ACROSS THE REST OF SOUTHWEST ALASKA,
STRONG SOUTHEASTERLY WINDS PICK UP THURSDAY AND PERSIST THROUGH
FRIDAY MORNING AS THE FRONT PROGRESSES INLAND AND THE LOW BEGINS
TO TRACK EAST IN THE SOUTHERN BERING.
-JH
LONG TERM FORECAST (DAYS 4 THROUGH 7)
KEY MESSAGES:
- A VERY STRONG LOW PRESSURE SYSTEM WILL DEVELOP OVER THE BERING
SEA BETWEEN LATER THIS WEEK.
- A SEPARATE LOW PRESSURE DEVELOPS IN THE GULF OF ALASKA LATER
THIS WEEK.
A LOW FORMING IN THE BERING SEA LATER THIS WEEK COULD INCLUDE
MOISTURE FROM THE REMNANTS OF EX-TYPHOON DUJUAN. DESPITE VARYING
DIFFERENCES IN THE LOW'S FORMATION AND ITS TRACK EASTWARD THE PAST
72 HOURS, A CONSISTENT THEME HAS BEEN THAT MOST OF THE MOISTURE
FROM THE EX- TYPHOON WILL REMAIN SOUTH OF THE ALEUTIAN CHAIN. THE
MOISTURE AND HEAT BEING ENTRAINED INTO THIS BERING SEA LOW WILL
BRING WIDESPREAD RAIN AND WIND GUSTS TO THE BERING SEA. MODELS
CONTINUE TO SHOW THIS BERING LOW STRENGTH RANGING FROM 960 TO 970
MB TODAY; DESPITE ITS MORE NORTHERLY TRACK AND MOST ENSEMBLE MODEL
GUIDANCE PLACING ITS FORMATION LOCATION FROM THE PRIBILOF ISLANDS
TO THE CENTRAL ALEUTIANS. ANOTHER COMMON THEME HAS BEEN THE
ALEUTIAN ISLANDS, FROM ATTU THROUGH DUTCH HARBOR, WILL LIKELY SEE
THE STRONGEST WINDS IN THIS STORM WITH GUSTS EXCEEDING 70 MPH AT A
40% TO 60% CHANCE THURSDAY TO SATURDAY.
AS FOR SOUTHCENTRAL AND THE GULF OF ALASKA REGION: A LOW THAT
TRACKS SOUTH OF THE ALEUTIANS WILL MAKE ITS WAY TO THE GULF OF
ALASKA REGION BY FRIDAY. AT THIS TIME, IT DOES APPEAR LIKELY THAT
A FAIRLY STRONG FRONT WILL MOVE INTO THE GULF OF ALASKA BY
DURING THE DAY THURSDAY BRINGING RAIN AND WIND TO THE GULF
REGION. WIND SPEEDS EXCEEDING 60 MPH ALONG THE EASTERN KENAI
PENINSULA AND THE GULF OF ALASKA RANGE FROM A 40% TO 60% CHANCE
LATE THIS WEEK AND INTO THE WEEKEND. THE GREATEST RAINFALL AMOUNTS
FROM THIS STORM CURRENTLY ARE ALONG THE COAST FROM THE EASTERN
KENAI PENINSULA TO CORDOVA FRIDAY AFTERNOON THROUGH SUNDAY
EVENING.
AVIATION
PANC...VFR CONDITIONS AND LIGHT AND VARIABLE WINDS LESS THAN 10 KT
WILL PERSIST THROUGH THE TAF PERIOD.
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