310
FXAK68 PAFC 270138
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
538 PM AKDT WED AUG 26 2026
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3: THIS
AFTERNOON THROUGH SATURDAY AFTERNOON)...
KEY MESSAGES:
- MOSTLY CLEAR SKIES THROUGH TOMORROW AFTERNOON/EVENING, THEN RAIN
AND WINDS RETURN AS A LOW PRESSURE SYSTEM MOVES ACROSS
SOUTHCENTRAL THROUGH SATURDAY AFTERNOON.
- FOR SUSITNA VALLEY, 48-HOUR RAIN TOTALS AROUND 0.5 TO 1.5 INCHES
WILL ALLOW FOR RISES ON MANY SMALL STREAMS AND RIVERS, AND
LOCALIZED PONDING IN LOW-LYING OR POOR DRAINAGE AREAS.
- WINDS PICK THROUGH COOK INLET AND ALONG PRINCE WILLIAM SOUND BY
LATE THURSDAY, WITH LOCALIZED GUSTY SOUTHEASTERLY GAP WINDS
THROUGH ANCHORAGE AND COPPER RIVER VALLEY.
DISCUSSION:
A DRIER, COOLER AIR MASS HAS LED TO CLEAR SKIES FOR MOST OF
SOUTHCENTRAL ALASKA THIS AFTERNOON. WITH CLEAR SKIES FORECAST TO
PERSIST THROUGH TONIGHT, THERE COULD BE A RETURN OF FOG EARLY
TOMORROW MORNING. CURRENT THINKING IS THAT ABUNDANT SUNSHINE TODAY
WILL HAVE HELPED MIX OUT SOME LOW LEVEL MOISTURE, LEADING TO LOWER
DEW POINTS. THIS MAY MEAN THAT IT WILL BE A BIT TOO DRY IN SOME
AREAS FOR THE LOWER LEVELS TO SATURATE AND PRODUCE FOG. STILL,
PATCHY FOG REMAINS POSSIBLE FROM MAT-SU DOWN TO ANCHORAGE AND
KENAI PENINSULA, WITH FOG CHANCES GREATER AROUND BODIES OF WATER
AND WETLANDS. THOUGH MOST AREAS WILL LIKELY SEE OVERNIGHT LOWS
REMAIN IN THE 40S (ESPECIALLY WHERE FOG DEVELOPS), ONE OTHER
THING TO WATCH FOR IS THE POTENTIAL FOR TEMPERATURES TO PLUMMET
INTO THE HIGH 30S OVERNIGHT. THIS WILL BE MOST LIKELY FOR
LOCATIONS THAT TEND TO LEAN COOLER, LIKE SOLDOTNA, EAST ANCHORAGE
(NEAR CAMPBELL TRACT), AND WILLOW.
WE'LL GET A CONTINUATION OF BENIGN WEATHER THROUGH THE FIRST HALF
OF TOMORROW, AND THEN CLOUDS WILL FILTER IN AHEAD OF AN ELONGATED
LOW MOVING INTO NORTON SOUND. AS ITS FRONT PUSHES EASTWARD INTO
SOUTHCENTRAL, EXPECT RAIN TO MOVE IN FROM WEST TO EAST BEGINNING
AS EARLY AS TOMORROW AFTERNOON FOR SUSITNA VALLEY, AND REACHING
PRINCE WILLIAM SOUND BY EARLY FRIDAY MORNING. WITH THE SYSTEM
BEING QUITE PROGRESSIVE, THE HEAVIEST RAIN WILL LIKELY MOVE
THROUGH WITHIN ABOUT 12 OR SO HOURS, LIMITING THE POTENTIAL FOR
SUSTAINED, HEAVY RAIN AND FLOODING CONCERNS. STILL, WITH RIVER
LEVELS STILL HIGH FROM OUR RAIN EARLIER THIS WEEK, PARTS OF
SUSITNA VALLEY WILL LIKELY SEE MINOR IMPACTS AS THE WATERSHED
ABSORBS THIS ADDITIONAL RAINFALL.
-KC
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(DAYS 1 THROUGH 3: THIS AFTERNOON THROUGH SATURDAY EVENING)...
KEY MESSAGES:
* A WIND ADVISORY HAS BEEN ISSUED FOR THE KUSKOKWIM DELTA,
WESTERN CAPES, AND NORTHERN BRISTOL BAY COAST FROM 10AM THURSDAY
TO 4PM FRIDAY. SOUTH TO SOUTHWEST WINDS 25 TO 35 MPH WITH GUSTS
UP TO 50 MPH ARE EXPECTED.
* MODERATE TO HEAVY RAIN ACROSS SOUTHWEST ALASKA THURSDAY
AFTERNOON THROUGH THURSDAY NIGHT. TAPERS TO SHOWERS THROUGH
FRIDAY.
* DRYING TREND ACROSS SOUTHWEST ALASKA AND THE ALASKA PENINSULA
SATURDAY.
* ANOTHER SYSTEM MOVES INTO THE BERING SATURDAY.
DISCUSSION:
SATELLITE IMAGERY REVEALS AN UPPER-LEVEL ABOUT TO EMERGE INTO THE
EXTREME WESTERN BERING SEA THIS AFTERNOON WHILE THE ATTENDANT
SURFACE LOW MOVE EASTWARD OUT AHEAD OF IT. A MOIST, WARM, AND
TROPICAL AIRMASS CONTINUES TO SURGE NORTHWARD THROUGH THE BERING
THE REST OF TODAY AND INTO THURSDAY. RAIN, MODERATE TO HEAVY AT
TIMES WILL WORK FROM THE WESTERN ALEUTIANS THIS AFTERNOON TO THE
PRIBILOF ISLANDS THIS EVENING AND WILL MAKE IT TO THE KUSKOKWIM
DELTA COAST BY EARLY THURSDAY MORNING. SOUTHERLY TO SOUTHEAST
WINDS ALONG THE COAST THURSDAY MORNING WILL TURN SOUTHWESTERLY BY
THURSDAY AFTERNOON. EXPECT GALE-FORCE WINDS ALONG THE KUSKOKWIM
DELTA COAST THURSDAY AFTERNOON INTO THURSDAY EVENING. SOUTHWEST
GUSTS INTO BETHEL WILL ALSO BE STRONG AT TIMES THURSDAY AFTERNOON
AND EVENING. THE CORRIDOR OF GALE-FORCE WINDS MOVES SOUTH INTO
BRISTOL BAY AS WELL BY THURSDAY EVENING. WITH THIS, A WIND
ADVISORY HAS BEEN ISSUED FOR THE KUSKOKWIM DELTA COAST, INTERIOR
KUSKOKWIM DELTA, THE WESTERN CAPES, AND THE NORTHERN BRISTOL BAY
COAST FROM 10 AM AKDT THURSDAY THROUGH 4 PM AKDT FRIDAY TO ADDRESS
THE GUSTY SOUTHERLY TO SOUTHWESTERLY WINDS. ADDITIONALLY, DUE TO
THE TROPICAL NATURE OF THE AIRMASS ACCOMPANYING THIS SYSTEM AND
STRONG JET DYNAMICS, A FEW LIGHTNING STRIKES WILL BE POSSIBLE (10
TO 30% CHANCE) ALONG THE ALEUTIAN CHAIN MARINE ZONES THIS EVENING
AND THURSDAY, AS WELL AS THE BRISTOL BAY WATERS BY THURSDAY
EVENING.
THE FETCH OF SOUTHWESTERLY WINDS INTO KUSKOKWIM BAY AND BRISTOL
BAY WILL BE LONG. WAVE HEIGHTS IN KUSKOKWIM BAY WILL BUILD THROUGH
THURSDAY WITH PEAK HEIGHTS AROUND 5 TO 7 FT NEAR THE COAST WITH 8
TO 11 FT AWAY FROM THE COAST. PEAK HEIGHTS SHOULD OCCUR THURSDAY
AFTERNOON THROUGH EVENING BEFORE SLOWLY SUBSIDING THROUGH FRIDAY.
WAVE HEIGHTS ACROSS BRISTOL BAY WILL BE SIMILAR WITH PEAK WAVE
HEIGHTS OCCURRING THURSDAY EVENING AND NIGHT BEFORE SLOWLY
SUBSIDING THROUGH FRIDAY.
ASIDE FROM THE WINDS AND ROUGH SEAS ALONG THE SOUTHWEST COAST,
THE OTHER MAIN THEME WITH THIS SYSTEM WILL BE THE HEAVY RAIN THAT
IT BRINGS. AS MENTIONED PREVIOUSLY, RAIN BEGINS AT THE KUSKOKWIM
DELTA COAST THURSDAY MORNING AND SPREADS ACROSS THE REST OF
SOUTHWEST THROUGH THE REST OF THE DAY. RAIN PICKS UP IN INTENSITY
THURSDAY AFTERNOON THROUGH THURSDAY NIGHT AS A STRONG SHORTWAVE
MOVES OVER THE AREA AND 850MB WINDS INCREASE. HEAVY RAIN TAPERS TO
SHOWERS ACROSS THE KUSKOKWIM DELTA BY THURSDAY EVENING AS HEAVY
RAIN PUSHES EAST INTO THE KUSKOKWIM VALLEY, BRISTOL BAY, AND ALONG
THE WESTERN ALASKA RANGE THURSDAY EVENING.
THE SURFACE LOW TRACKS INTO NORTON SOUND BY FRIDAY MORNING AS THE
MAIN UPPER-LEVEL TROUGH BEGINS TO MOVE INTO SOUTHWEST FROM THE
BERING. THIS WILL KEEP STEADY RAIN GOING ACROSS THE MOUNTAIN
RANGES AIDED BY SOUTHWESTERLY UPSLOPE FLOW. COLDER AIR MOVES INTO
SOUTHWEST FROM THE BERING AND CREATES MORE OF A SHOWERY REGIME
ACROSS THE REST OF THE AREA. SHOWERS WILL TAPER OFF FROM WEST TO
EAST THROUGH SATURDAY AFTERNOON AS THE AREA FINALLY BEGINS TO SEE
A DRYING TREND. WHEN ALL IS SAID AND DONE, ABOUT 0.50 TO 2.5
INCHES OF RAIN WILL FALL ACROSS SOUTHWEST FROM EARLY THURSDAY
MORNING THROUGH EARLY SATURDAY MORNING. THE HIGHEST TOTALS WILL BE
ALONG THE WESTERN ALASKA RANGE WITH THE HELP OF THE SOUTHWESTERLY
UPSLOPE FLOW. THE LOWER TOTALS LOOK TO FALL ACROSS INTERIOR
BRISTOL BAY WHEN FLOW TURNS WEST-SOUTHWEST THURSDAY EVENING AND
NIGHT WILL HELP DOWNSLOPE SOME OF THE HIGHER MOISTURE CONTENT.
ANOTHER PUSH OF WARM, MOIST, TROPICAL AIR MOVES INTO THE SOUTHERN
BERING FROM THE NORTH PACIFIC SATURDAY MORNING THROUGH SATURDAY
EVENING. THE SETUP FOR THIS SYSTEM WILL BE SIMILAR BUT NOT THE
SAME FOR THE SYSTEM COMING UP FOR TOMORROW/THURSDAY INTO FRIDAY.
ANOTHER UPPER-LEVEL LOW WILL TRACK ACROSS KAMCHATKA SATURDAY
MORNING AND MOVE INTO THE EXTREME WESTERN BERING THROUGH SATURDAY
EVENING. BOTH THE UPPER-LEVEL SYSTEM AND SURFACE LOW LOOK TO BE
WEAKER SATURDAY IN CONTRAST TO THE SYSTEM FOR THURSDAY/FRIDAY.
NONETHELESS, RAIN WILL MOVE INTO SHEMYA BY SATURDAY MORNING AND
ADVANCE NORTH AND EASTWARD ACROSS THE BERING TO NEAR THE PRIBILOF
ISLANDS BY SATURDAY EVENING. SUSTAINED WINDS WITH THIS SYSTEM LOOK
TO BE SMALL-CRAFT OR LESS AT THIS TIME. STAY TUNED FOR FORECAST
UPDATES AS THE STORMY PATTERN ACROSS THE BERING CONTINUES TO
UNFOLD.
LONG TERM FORECAST (DAYS 4 THROUGH 7: SUNDAY THROUGH WEDNESDAY)
THE PROGRESSIVE PATTERN LOOKS TO CONTINUE INTO EARLY NEXT WEEK AS
MULTIPLE SYSTEMS MOVE THROUGH SOUTHERN ALASKA. THIS WILL
GENERALLY BRING PERIODS OF ACTIVE WEATHER, WITH SOME LULLS BETWEEN
SYSTEMS.
TROUGHING EXITS SOUTHCENTRAL EARLY SUNDAY MORNING WITH THE
SURFACE LOW MOVING INTO THE NORTHERN GULF. THIS WILL INCREASE
NORTHWESTERLY WINDS THROUGH THE BARREN ISLANDS AND AROUND KODIAK
ISLAND/THE AKPEN TO SMALL-CRAFT FORCE SUNDAY INTO MONDAY. A
SHORTWAVE RIDGE MOVES THROUGH SOUTHERN ALASKA ON SUNDAY. A FEW
SHORTWAVES MAY RIDE THE PERIPHERY OF THE RIDGE, WHICH MAY INDUCE
ISOLATED TO SCATTERED SHOWERS IN HIGHER ELEVATIONS OF SOUTHWEST
AND SOUTHCENTRAL, OTHERWISE SUNDAY LOOKS TO BE MOSTLY CALM INLAND.
BY SUNDAY EVENING, AN ARCTIC LOW DIVES SOUTH INTO THE WESTERN
INTERIOR. THIS LOW CONTINUES SOUTHEASTWARD THROUGH SOUTHCENTRAL
AND INTO THE ALASKA PANHANDLE BY WEDNESDAY. MODELS DIVERGE WITH
EXACT TIMING BUT AGREE ON FEATURES WITH THIS LOW. AS THE LOW MOVES
SOUTH, TEMPERATURES WILL COOL. THIS WILL ESPECIALLY BE THE CASE
FOR SOUTHWEST AS MANY LOCATIONS MAY STRUGGLE TO GET ABOVE THE MID
50S MONDAY-WEDNESDAY. LOWEST ELEVATIONS OF SOUTHCENTRAL WILL BE
SLIGHTLY WARMER, THOUGH LIKELY STRUGGLE TO REACH 60. SCATTERED
SHOWERS WILL CONTINUE ACROSS EASTERN PORTIONS OF SOUTHWEST AND
MUCH OF SOUTHCENTRAL AS THE UPPER LOW PASSES THROUGH. COOLER
TEMPERATURES WILL DROP SNOW LEVELS TO AROUND 4000-5000 FT. SOME
TERMINATION DUST (SNOWFALL) MAY BE SEEN ON THE HIGHEST PEAKS OF
THE CHUGACH FRONT RANGE AND KENAI MOUNTAINS, AS WELL AS SOME LOWER
PORTIONS OF THE ALASKA RANGE BY THE MIDDLE OF NEXT WEEK. A
SURFACE LOW LOOKS TO DEVELOP IN THE GULF MONDAY INTO TUESDAY AND
MAINTAIN SMALL-CRAFT NORTHWESTERLY WINDS AROUND KODIAK ISLAND,
THE AKPEN, AND THROUGH THE BARREN ISLANDS INTO THE GULF THROUGH
WEDNESDAY MORNING.
FOR THE SOUTHERN AKPEN, THE ALEUTIANS, AND THE BERING, MOST
MODELS AGREE WITH A FLAT RIDGE PERSISTING OVERHEAD THROUGH
TUESDAY, BUT DIVERGE ON SURFACE FEATURES BELOW. SOME PRECIPITATION
LOOKS LIKELY MONDAY-TUESDAY IN THE AKPEN AS NORTHWEST WINDS
UPSLOPE AGAINST THE MOUNTAINS. OTHER THAN THAT, THERE ARE MAJOR
DIFFERENCES BETWEEN MODELS REGARDING POTENTIAL SYSTEMS MOVING INTO
THE BERING. EVEN WITH THESE DIFFERENCES, AREAS OF RAIN AND SMALL-
CRAFT WINDS ARE POSSIBLE THROUGHOUT THE BERING AND ALEUTIANS
THROUGH WEDNESDAY. IF A SYSTEM IS ABLE TO TRACK THROUGH THE BERING
AND REACH THE COAST, SOUTHWEST MAY RECEIVE ADDITIONAL RAINFALL
TUESDAY INTO WEDNESDAY. DETAILS WILL BECOME MORE CLEAR IN THE
COMING DAYS.
- PA
AVIATION
PANC...VFR CONDITIONS AND LIGHT WINDS WILL PERSIST. WHILE PATCHY
FOG NEAR THE AIRPORT EARLY THURSDAY MORNING CANNOT BE FULLY RULED
OUT, IT LOOKS UNLIKELY AT THIS TIME.
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