914
FXAK68 PAFC 250226
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
626 PM AKDT MON AUG 24 2026
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3/ TODAY
THROUGH THURSDAY)...
KEY MESSAGE:
- SPECIAL WEATHER STATEMENT HAS BEEN ISSUED FOR STRONG WINDS
TOMORROW, TUESDAY FOR ANCHORAGE, ANCHORAGE HILLSIDE, PALMER AND
BUTTE.
DISCUSSION:
A BRIEF PERIOD OF RELATIVELY QUIET WEATHER CONTINUES ACROSS MUCH
OF SOUTHCENTRAL TODAY AS AN UPPER-LEVEL RIDGE SHIFTS EASTWARD
ACROSS THE REGION. HOWEVER, THIS BREAK WILL BE SHORT-LIVED AS A
POTENT SHORTWAVE TROUGH APPROACHES FROM THE SOUTHWEST TONIGHT INTO
TUESDAY. INCREASING SOUTHWESTERLY FLOW ALOFT AHEAD OF THE TROUGH
WILL TRANSPORT A PLUME OF MOISTURE INTO SOUTHCENTRAL, WITH RAIN
INITIALLY DEVELOPING ACROSS THE SUSITNA VALLEY BEFORE BECOMING
MORE WIDESPREAD TUESDAY EVENING.
THE SHORTWAVE TAKES ON A NEGATIVELY TILTED ORIENTATION AS IT LIFTS
NORTHEAST ACROSS SOUTHCENTRAL ON TUESDAY, PROVIDING STRONGER
UPPER-LEVEL FORCING AS THE ASSOCIATED FRONT PUSHES INLAND.
WIDESPREAD RAIN IS EXPECTED ACROSS MUCH OF THE REGION, WITH THE
GREATEST RAINFALL AMOUNT FAVORED ACROSS THE NORTHERN AND EASTERN
SUSITNA VALLEY WHERE PERSISTENT SOUTHERLY FLOW WILL ENHANCE
UPSLOPE PRECIPITATION ALONG THE TALKEETNA MOUNTAINS AND ALASKA
RANGE. MEANWHILE, DOWNSLOPE FLOW WILL LIKELY RESULT IN LOWER
RAINFALL AMOUNTS FOR PORTIONS OF THE WESTERN KENAI PENINSULA AND
ANCHORAGE.
WINDS WILL ALSO BECOME A SIGNIFICANT COMPONENT OF TUESDAY'S
SYSTEM AS THE PRESSURE GRADIENT TIGHTENS CONSIDERABLY ACROSS
SOUTHCENTRAL. STRONG SOUTHEASTERLY GAP WINDS ARE EXPECTED THROUGH
TURNAGAIN ARM AND THE HIGHER TERRAIN SURROUNDING ANCHORAGE, WITH
WINDS SPILLING INTO THE ANCHORAGE HILLSIDE. GUSTS AROUND 40 KT ARE
POSSIBLE ACROSS PORTIONS OF ANCHORAGE, INCLUDING THE AIRPORT,
PARTICULARLY TUESDAY AFTERNOON AND EARLY EVENING. STRONG WINDS
ARE ALSO EXPECTED THROUGH THE KNIK VALLEY AND COPPER RIVER BASIN
GAPS AS THE FRONT MOVES THROUGH.
THE SHORTWAVE AND ASSOCIATED SURFACE FRONT LIFT NORTH AND EAST
TUESDAY NIGHT INTO WEDNESDAY, ALLOWING WIDESPREAD PRECIPITATION TO
GRADUALLY DIMINISH FROM WEST TO EAST. LINGERING SHOWERS REMAIN
POSSIBLE WEDNESDAY, PARTICULARLY ALONG THE MOUNTAINS, AS A
TRAILING UPPER-LEVEL DISTURBANCE CROSSES THE REGION. OTHERWISE,
CONDITIONS TREND QUIETER THROUGH THE DAY AS WEAK RIDGING BEGINS
TO BUILD BACK ACROSS SOUTHCENTRAL. THIS RESPITE LOOKS RELATIVELY
BRIEF, HOWEVER, AS THE UPPER-LEVEL PATTERN REMAINS PROGRESSIVE AND
ANOTHER TROUGH APPROACHES ALASKA FROM THE WEST HEADING TOWARD THE
LATTER HALF OF THE WEEK.
LM
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(DAYS 1 THROUGH 3: THIS AFTERNOON THROUGH THURSDAY EVENING)...
AFTERNOON SATELLITE IMAGERY REVEALS A TROUGH STRETCHING ACROSS
SIBERIA AND INTO THE BERING SEA. A SURFACE LOW CONTINUES TO MOVE
THROUGH THE CHUKCHI SEA AS ITS FRONT IS CURRENTLY OVER INTERIOR
ALASKA AND INTERIOR SOUTHWEST ALASKA. RAIN WILL CONTINUE ACROSS
SOUTHWEST THROUGH TUESDAY AS THE BASE OF THE TROUGH CONTINUES TO
MOVE ACROSS THE NORTHERN AND CENTRAL BERING. MOST RAIN ON TUESDAY
WILL FALL ALONG THE TERRAIN WHICH WILL BE AIDED BY WESTERLY
UPSLOPE FLOW. STEADY RAIN TUESDAY MORNING TAPERS OFF TO SHOWERS
TUESDAY AFTERNOON AND EVENING AS THE MAIN TROUGH AXIS AND STEADY
RAIN MOVES EAST TO SOUTHCENTRAL. WEDNESDAY WILL SEE DRIER AND
QUIETER WEATHER BEFORE THE NEXT BERING SYSTEM MOVES IN FOR
THURSDAY.
SPEAKING OF THE NEXT BERING SYSTEM, IT WILL BEGIN TO GATHER
TUESDAY AFTERNOON AS UPPER-LEVEL NORTH PACIFIC ENERGY INTERACTS
WITH AN UPPER-LEVEL OVER KAMCHATKA. THIS INTERACTION WILL HELP
DEEPEN A SURFACE LOW BETWEEN KAMCHATKA AND THE WESTERN ALEUTIANS.
WARM, MOIST, TROPICAL AIR WILL RIDE NORTHWARD FROM THE PACIFIC
AND INTO THE BERING SEA BEGINNING WEDNESDAY. AT 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.
MODERATE TO HEAVY RAIN THEN MOVES INTO SOUTHWEST STARTING WITH
THE KUSKOKWIM DELTA COAST BY THURSDAY MORNING AND ADVANCES INLAND
ACROSS THE REST OF SOUTHWEST THROUGH THURSDAY AFTERNOON AND
EVENING. GALE-FORCE SOUTHERLY TO SOUTHWESTERLY WINDS ARE LIKELY
(60 TO 70% CHANCE) ACROSS THE WESTERN BERING WEDNESDAY AND
ADVANCING ACROSS THE BERING TO THE EASTERN BERING AND KUSKOKWIM
BAY BY THURSDAY AFTERNOON AND EVENING. THERE IS LITTLE THREAT WITH
COASTAL FLOODING (10% OR LESS) ALONG THE KUSKOKWIM DELTA COAST
WITH THIS SYSTEM DUE TO THE LOWER TIDE CYCLE THE AREA IS CURRENTLY
IN. THERE WILL STILL BE ROUGH SEAS JUST OFF THE COAST WITH WAVE
HEIGHTS APPROACHING 8 FEET BY THURSDAY EVENING. GUSTY WINDS WILL
MAKE IT INLAND OF THE KUSKOKWIM DELTA COAST WHERE LOCATIONS SUCH
AS BETHEL WILL CONTEND WITH GUSTY CONDITIONS WITH ONGOING MODERATE
TO HEAVY RAIN. STAY TUNED FOR FORECAST UPDATES REGARDING THE
EVOLUTION OF THIS NEXT BERING SYSTEM.
LONG TERM FORECAST (DAYS 4 THROUGH 7: FRIDAY THROUGH MONDAY)
AN ACTIVE, PROGRESSIVE PATTERN CONTINUES THROUGH THE END OF THE
WEEK AND INTO EARLY NEXT WEEK AS MULTIPLE SYSTEMS QUICKLY TRACK
FROM WEST TO EAST. THIS WILL GENERALLY BRING PERIODS OF ACTIVE
WEATHER, WITH BRIEF LULLS IN BETWEEN FOR MOST LOCATIONS.
BY FRIDAY MORNING, A 990 MB LOW WILL HAVE TRACKED JUST EAST OF ST.
LAURENCE ISLAND AND BEGINS TO MOVE INLAND NEAR THE NORTON SOUND,
BRINGING MODERATE TO HEAVY PRECIPITATION ACROSS MUCH OF
SOUTHWESTERN ALASKA. CONCURRENTLY, SOUTHWESTERLY SMALL-CRAFT TO
GALE- FORCE WINDS WILL CONTINUE TO PUSH INTO BRISTOL BAY AND THE
KUSKOKWIM DELTA COAST. WIDESPREAD PRECIPITATION WILL ALSO FILTER
INTO SOUTHCENTRAL, AND WILL BE PARTICULARLY HEAVY FOR THE
NORTHERN GULF COAST AND TALKEETNA MOUNTAINS. TURNAGAIN/KNIK GAPS
WINDS WILL LIKELY RETURN FRIDAY, BRINGING POTENTIAL FOR GUSTY
CONDITIONS AROUND ANCHORAGE AND PALMER. RIVER LEVELS ACROSS THE
SUSITNA VALLEY, SUCH AS THE YENTNA RIVER AT LAKE CREEK WILL HAVE
TO BE MONITORED CLOSELY WITH THIS SYSTEM FOR POTENTIAL FLOODING
CONCERNS.
BY SATURDAY MORNING, THE TROUGH EJECTS A SURFACE LOW INTO THE
GULF, CAUSING RAINFALL TO TAPER OFF FROM WEST TO EAST ACROSS THE
MAINLAND AS THIS LOW CONTINUES TOWARD THE ALASKAN PANHANDLE. SOME
SHOWERS MAY LINGER IN SPOTS, PARTICULARLY FOR PRINCE WILLIAM
SOUND AND THE WESTERN/CENTRAL CHUGACH, THOUGH CONDITIONS WILL
GRADUALLY IMPROVE AS RIDGING REBUILDS OVER THE REGION. A SEPARATE
NORTH PACIFIC LOW MOVES INTO THE WESTERN BERING BY SATURDAY WHICH
WILL LIKELY BRING ANOTHER WAVE OF PRECIPITATION TO THE
WESTERN/CENTRAL ALEUTIANS.
DETERMINISTIC SOLUTIONS BEGIN TO DIFFER SUBSTANTIALLY BY MONDAY.
HOWEVER, ENSEMBLE MEANS SHOW A BROAD RIDGE AMPLIFYING JUST SOUTH
OF THE ALEUTIANS, WHICH COULD SET UP A PERIOD OF MOIST FLOW.
ANOTHER SHORTWAVE APPEARS TO WORK DOWN THE MAINLAND BY MONDAY. IF
THIS FEATURE CAN TAP INTO THIS MOISTURE, ANOTHER ROUND OF
WIDESPREAD PRECIPITATION COULD BE ON TRACK FOR MUCH OF THE
SOUTHERN ALASKA EARLY NEXT WEEK.
-CW
AVIATION
PANC...CLOUDS WILL BE ON THE INCREASE THIS AFTERNOON AND EVENING
AS A FRONTAL SYSTEM ADVANCES TOWARD THE TERMINAL FROM THE WEST.
VFR CONDITIONS WILL PERSIST THROUGH TONIGHT, ALTHOUGH LIGHT RAIN
IS EXPECTED TO DEVELOP BY THIS EVENING. A SOUTHEASTERLY TURNAGAIN
ARM WIND WILL DEVELOP OVERNIGHT WITH THESE WINDS BEGINNING TO MOVE
OVER THE TERMINAL BY EARLY TUESDAY MORNING. SUSTAINED WINDS OF 15
TO 30 MPH ARE LIKELY ALONG WITH GUSTS UP TO 40 MPH. OCCASIONAL
GUSTS OF 45 TO 50 MPH ARE POSSIBLE ( 30-40%) DURING THE PEAK OF
THE WIND EVENT, LIKELY BETWEEN 8 AM AND 6 PM. ANY HEAVIER RAINFALL
SHOULD HOLD OFF THROUGH THE FIRST HALF OF TUESDAY DUE TO THE THESE
WINDS. HOWEVER, STEADIER RAIN IS EXPECTED BY LATE TUESDAY
AFTERNOON AS THE WINDS BEGIN TO DIMINISH AND THE FRONT MOVES INTO
THE AREA. MFVR CIGS AND VIS ARE EXPECTED WITH THIS ROUND OF STEADY
RAINFALL. THERE IS A LOW CHANCE ( 10-20%) THAT CEILINGS MAY FALL
TO IFR IN THE WAKE OF THIS SYSTEM OVERNIGHT TUESDAY INTO EARLY
WEDNESDAY MORNING AS THE WIND FLOW ALOFT WEAKENS.
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