501
FXAK68 PAFC 260155
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
555 PM AKDT TUE AUG 25 2026
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
KEY MESSAGES:
- SPECIAL WEATHER STATEMENT FOR STRONG WINDS IN ANCHORAGE,
ANCHORAGE HILLSIDE, AND MAT-SU THROUGH 7 PM THIS EVENING.
- RAINFALL TODAY AND FRIDAY IN THE SUSITNA VALLEY WILL ALLOW FOR
RISES ON MANY SMALL STREAMS AND RIVERS, AND LOCALIZED PONDING IN
LOW- LYING OR POOR DRAINAGE AREAS.
DISCUSSION:
CURRENTLY, A SHORTWAVE CONTINUES TO SWEEP ACROSS MAINLAND ALASKA
AND HAS BROUGHT WIDESPREAD SHOWERS ACROSS MUCH OF SOUTHCENTRAL. A
SURFACE LOW CURRENTLY POSITIONED IN THE COOK INLET HAS RAMPED UP
SOUTHEAST WINDS, ESPECIALLY THROUGH GAPS LIKE TURNAGAIN ARM AND
THE COPPER VALLEY. THROUGHOUT THE EVENING, BOTH THE SHORTWAVE AND
THE SURFACE LOW MOVE INTO THE GULF. PRECIPITATION WILL SLOWLY
TAPER OFF OVERNIGHT INTO TOMORROW MORNING, FIRST IN THE KENAI
PENINSULA, THEN ANCHORAGE AND MAT-SU, AND FINALLY THE COPPER RIVER
BASIN TOMORROW MORNING. SOUTHEAST GAP WINDS WILL ALSO WEAKEN
OVERNIGHT AS WELL. KODIAK ISLAND HAS AVOIDED MUCH OF THE RAIN AND
WILL CONTINUE TO DO SO TONIGHT.
WITH THE LOW IN THE GULF BY TOMORROW MORNING AND CONTINUING
EASTWARD, THE WEATHER WILL BE MOSTLY BENIGN ACROSS SOUTHCENTRAL
TOMORROW AND THURSDAY AS ZONAL TO NORTHWEST FLOW TAKES SHAPE
OVERHEAD. THE LOW IN THE GULF WILL ENHANCE NORTHWEST WINDS TO
SMALL-CRAFT THROUGH THE BARREN ISLANDS TOMORROW. ADDITIONALLY, A
SHORTWAVE MOVES THROUGH THE UPPER SUSITNA VALLEY AND WRANGELL
MOUNTAINS TOMORROW THROUGH THURSDAY MORNING, WHICH MAY BRING SOME
SCATTERED SHOWERS TOMORROW AFTERNOON AND EVENING. OTHERWISE, MOST
OF SOUTHCENTRAL WILL BE CALM AND DRY UNDERNEATH PARTLY CLOUDY
SKIES.
CLOUD COVER INCREASES THURSDAY AFTERNOON AND EVENING FROM WEST TO
EAST AS THE NEXT SYSTEM APPROACHES FROM THE BERING. WIDESPREAD
PRECIPITATION WILL SPILL OVER THE ALASKA RANGE INTO KODIAK ISLAND
AND WESTERN SOUTHCENTRAL LATE THURSDAY NIGHT AND SPREAD ACROSS
ALL OF SOUTHCENTRAL ON FRIDAY. PRECIPITATION WILL BE HEAVIEST
ALONG THE NORTHERN GULF COAST INTO THE CHUGACH MOUNTAINS. SOUTHWEST
WINDS WILL STRENGTHEN IN THE WESTERN GULF AND SHELIKOF STRAIT TO
SMALL-CRAFT BY FRIDAY MORNING. ADDITIONALLY, A SURFACE LOW LOOKS
TO DEVELOP IN THE NORTHERN GULF FRIDAY MORNING. DEPENDING ON THE
STRENGTH OF THE PRESSURE GRADIENT WITH THE COASTAL RIDGE, THIS
WILL ENHANCE EASTERLY AND SOUTHEASTERLY WINDS FRIDAY, ESPECIALLY
IN PROPERLY ALIGNED GAPS (TURNAGAIN ARM, KNIK RIVER, AND BARRIER
JET).
- PA
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(DAYS 1 THROUGH 3: TONIGHT THROUGH FRIDAY EVENING)...
A STRONG COLD FRONT IS CONTINUING TO DRIVE EAST OVER THE ALASKA
RANGE THIS AFTERNOON. ITS PARENT LOW, SITUATED NEAR GALENA AT 4
PM, IS TRAILING THE FRONT ALLOWING FOR A FEW SCATTERED SHOWERS TO
REMAIN OVER THE Y-K DELTA. BEHIND THE FRONT, SCATTERED LOW AND
MID-LEVEL CLOUDS ARE LINGERING; HOWEVER, DRIER AND MORE STABLE AIR
IS BEGINNING TO ERODE THESE CLOUD DECKS. TONIGHT, THE WEST-
NORTHWESTERLY FLOW IN THE WAKE OF THE LOW WILL LIKELY ADVECT THE
MARINE LAYER BACK OVER THE KUSKOKWIM DELTA AND PARTS OF THE
BRISTOL BAY COAST GIVEN THE RETURN TO A WEAK ONSHORE FLOW AHEAD OF
A BUILDING RIDGE OF HIGH PRESSURE OVER THE BERING.
LOOKING AHEAD TO WEDNESDAY MORNING, TRANSIENT UPPER LEVEL RIDGING
WILL MOST LIKELY ENCOMPASS MUCH OF THE BERING SEA, WHICH WILL
RESULT IN A SHORT LIVED PERIOD OF QUIETER WEATHER (OUTSIDE OF FOG
AND LOW STRATUS) FOR THE BERING AND ALEUTIAN CHAIN. MOS GUIDANCE
IS STILL HINTING AT FOG AND LOW STRATUS MAKING ITS WAY ONSHORE
WEDNESDAY MORNING FOR COASTAL PORTIONS OF SOUTHWEST ALASKA,
EXTENDING AS FAR INLAND AS BETHEL. A WEAK UPPER-LEVEL WAVE WILL
MOVE EAST FROM NORTON SOUND TO THE ALASKA RANGE NEAR MCGRATH.
INSTABILITY ASSOCIATED WITH THIS FEATURE WILL LIKELY ALLOW FOR A
FEW SCATTERED SHOWERS TO POP UP, MAINLY OVER THE HIGHER TERRAIN
ALONG THE KUSKOKWIM RIVER VALLEY.
IN THE WAKE OF THE RIDGE, THE KAMCHATKA FRONT WILL BEGIN TO LIFT
NORTHEASTWARD ACROSS THE BERING SEA WEDNESDAY MORNING. WARM,
MOIST, TROPICAL AIR WILL BE TRANSPORTED NORTHWARD FROM THE PACIFIC
AND INTO THE BERING SEA DURING THIS TIME AS AN ATMOSPHERIC RIVER
WILL ALSO ACCOMPANY THIS SYSTEM AS MODERATE TO HEAVY RAIN MOVES
INTO SHEMYA WEDNESDAY MORNING. THE HEAVY RAIN AXIS SHIFTS EAST BY
WEDNESDAY AFTERNOON AND EVENING AS RAIN MOVES INTO THE PRIBILOF
ISLANDS BY THEN.
ON THE WIND SIDE OF THINGS, LOW END SOUTHWESTERLY GALES WITH THIS
SYSTEM ARE EXPECTED TO TRAVERSE THE BERING AND ALEUTIAN CHAIN
BEGINNING AS EARLY AS LATE WEDNESDAY MORNING. THESE WINDS ARE ON
TRACK TO REACH THE PRIBILOF ISLANDS BY THURSDAY MORNING. FROM
HERE, GALES TRANSLATE EASTWARD ACROSS THE EASTERN BERING THURSDAY
AFTERNOON. MODELS HAVE FLIPPED AGAIN FROM THEIR OVERNIGHT
SOLUTIONS, WITH A STRONGER FRONT AND DEVELOPING LOW TRACKING
FARTHER NORTH, SIMILAR TO THE SOLUTIONS 24+ HOURS AGO. AS SUCH,
THE STRONGEST WINDS AGAIN LOOK TO PUSH FROM KUSKOKWIM BAY ACROSS
THE DELTA BEFORE THIS CORE OF STRONG WINDS SHIFTS SOUTH AND OVER
BRISTOL BAY. ONE OTHER CHANGE IS THAT THE TRAILING WAVE ALSO LOOKS
STRONGER WITH A PERSISTENTLY STRONG SOUTHWESTERLY WIND FLOW
PUSHING BACK ACROSS KUSKOKWIM BAY AND DELTA INTO FRIDAY. THIS
CONTINUED PUSH OF WINDS MAY RESULT IN HIGHER WAVES AND ROUGH SEAS
ALONG THE KUSKOKWIM BAY COAST, ESPECIALLY DURING HIGH TIDE FRIDAY
AFTERNOON.
REGARDLESS OF THE EXACT STORM TRACK, A ROUND OF HEAVY RAINFALL IS
ON TRACK TO ARRIVE THURSDAY MORNING TO SOUTHWEST ALASKA AND
CONTINUE ON THROUGH FRIDAY, LIKELY ADDING UP TO 1 TO 2 INCHES OF
RAINFALL FOR SOME AREAS. IT IS BEGINNING TO LOOK A LOT LIKE
AUTUMN!
-TM/AM
LONG TERM FORECAST (DAYS 4 THROUGH 7: SATURDAY THROUGH MONDAY)
THE ACTIVE, PROGRESSIVE PATTERN CONTINUES INTO EARLY NEXT WEEK AS
MULTIPLE SYSTEMS TRACK FROM WEST TO EAST. THIS WILL GENERALLY
BRING PERIODS OF ACTIVE WEATHER, WITH LULLS IN BETWEEN FOR
SOUTHWEST AND SOUTHCENTRAL ALASKA.
BY SATURDAY, A TROUGH WILL BE OVER MUCH OF ALASKA. THIS WILL
LIKELY BRING WIDESPREAD RAINFALL AND ELEVATED WINDS TO COASTAL
AND MAINLAND SOUTHCENTRAL AND SOUTHWEST ALASKA. THIS TROUGH WILL
QUICKLY PUSH EASTWARD AND WEAK RIDGING/ZONAL FLOW WILL SET IN,
ALLOWING FOR WIND SPEEDS AND RAINFALL TO DWINDLE. THE BERING WILL
SEE A TROUGH WITH AN ASSOCIATED FRONT MOVE IN FROM THE WEST.
SUNDAY WILL SEE THIS FRONT PROGRESS EASTWARD, LEADING TO A SWATH
OF RAINFALL AND GUSTY WINDS ACROSS THE ALEUTIANS. HOWEVER, THE
EXACT INTENSITY AND PATH OF THIS WEATHER IS UNCERTAIN AS OF NOW.
FOR SOUTHCENTRAL, RIDGING WILL CONTINUE, WITH LIGHTER WINDS AND
CLEARER SKIES.
UNCERTAINTY INCREASES ON MONDAY AS A LOW MOVES INTO THE BERING.
THE EXACT TRACK OF IT CANNOT BE DETERMINED AT THIS POINT, BUT
GUSTY WINDS AND RAINFALL WILL LIKELY ARISE SOMEWHERE ALONG THE
ALEUTIANS. A PLUME OF MOISTURE RIDING UP AND AROUND A RIDGE IN THE
NORTH PACIFIC WILL LEAD TO HEAVIER RAINFALL WITH THIS LOW. AGAIN,
THE EXACT RAINFALL AMOUNTS WILL DEPEND ON THE TRACK OF THE LOW
MOVING INTO THE BERING. SOUTHCENTRAL WILL HAVE A LOW MOVE INTO
THE GULF OF ALASKA. ONCE AGAIN, THERE IS MUCH UNCERTAINTY WITH
WIND SPEEDS AND RAINFALL INTENSITY WITH THEM BEING HIGHLY
DEPENDENT ON HOW STRONG THE LOW IS.
-JAR
AVIATION
PANC...THE STRONG SOUTHEASTERLY WINDS GUSTING 30 TO 40 KTS WILL
CONTINUE THROUGH THE AFTERNOON AND THEN TAPER OFF THROUGHOUT THE
EVENING. THIS DROP IN WINDS WILL LIKELY HAPPEN RAPIDLY AFTER THE
FRONT PASSES THROUGH THE AREA FROM THE WEST. RAINFALL WILL ALSO
PERSIST UNTIL THE FRONT PASSES. IN SPITE OF THE RAIN, THE STRONG
WINDS ARE LIKELY TO KEEP VISIBILITY IN VFR RANGE AND CEILINGS JUST
DIPPING TO MVFR LEVELS.
BY MIDNIGHT, WINDS SHOULD HAVE TAPERED OFF AND ANY LINGERING
SHOWERS ENDED. THE ONLY REAL QUESTION AFTER THAT IS WHETHER THERE
WILL BE ANY DEVELOPMENT OF LOW CLOUDS OR FOG FOR THE EARLY
MORNING HOURS. THIS IS HEAVILY DEPENDENT ON SKIES CLEARING ENOUGH
BEHIND THE FRONT AS WELL AS WINDS BECOMING NEARLY CALM. NO MODEL
GUIDANCE IS SHOWING FOG OR STRATUS SO AM JUST KEEPING A FEW LOWER
CLOUDS IN THE TAF FOR NOW.
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