160
FXAK68 PAFC 261334
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
534 AM AKDT WED AUG 26 2026
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
KEY MESSAGES:
- ANOTHER ROUND OF RAINFALL THURSDAY NIGHT THROUGH FRIDAY OVER THE
SUSITNA VALLEY WILL ALLOW FOR RISES ON MANY SMALL STREAMS AND
RIVERS, AND LOCALIZED PONDING IN LOW-LYING OR POOR DRAINAGE AREAS.
DISCUSSION:
THE SYSTEM THAT BROUGHT WIDESPREAD RAINFALL ACROSS SOUTHCENTRAL
YESTERDAY HAS MOSTLY DEPARTED THE AREA AS OF THIS MORNING. THE LOW
HAS LIFTED INTO THE NE CORNER OF ALASKA WITH FRONT NOW PUSHING
ACROSS THE CANADIAN YUKON. THERE ARE SOME LINGERING SHOWERS STILL
ONGOING THIS MORNING OVER THE SE CORNER OF THE COPPER BASIN, BUT
THESE WILL CONTINUE TO WEAKEN AND DISSIPATE THROUGH THE MORNING.
WHILE A DRIER AIRMASS HAS MOVED IN BEHIND THE AFOREMENTIONED SYSTEM,
SOME AREAS HAVE HUNG ON TO A MID-LEVEL CLOUD DECK OVERNIGHT.
TEMPERATURES HAVE ALSO FALLEN AS THE DRIER AIRMASS PUSHES IN WITH
MORNING TEMPERATURES DROPPING INTO THE 40S FOR MOST AREAS. FOG HAS
TRIED TO FORM IN SOME OF THESE AREAS THAT HAVE CLEARED OUT, BUT HAVE
HAD TO COMPETE WITH FALLING DEWPOINTS. THE MOST WIDESPREAD AREA OF
FOG HAS DEVELOPED ALONG PORTIONS OF THE GLENN HIGHWAY NORTH OF
ANCHORAGE AND INTO PALMER-WASILLA AND ON UP TOWARDS WILLOW. MOST OF
THE FOG HAS BEEN RELATIVELY LIGHT WITH VISIBILITIES OF 1 TO 3 MILES,
BUT THERE HAVE BEEN SOME POCKETS OF DENSE FOG WHERE VISIBILITY HAS
DROPPED BELOW 1 MILE AT TIMES. AS SUCH, HAVE ISSUED AN SPS FOR FOG
IN THIS AREA UNTIL 9 AM THIS MORNING. COULD SEE A FEW MORE AREAS OF
FOG POP UP NEAR SUNRISE BEFORE DIURNAL HEATING STARTS TO MIX OUT THE
BOUNDARY LAYER.
MORE SEASONABLE TEMPERATURES TODAY WITH DRIER CONDITIONS AS WE
REMAIN UNDER WESTERLY TO NORTHWESTERLY FLOW ALOFT. A WEAK SHORTWAVE
MOVING THROUGH THE FLOW LATER TODAY COULD SPARK SOME SHOWERS ALONG
THE ALASKA RANGE AND TALKEETNA MOUNTAINS. AN UPPER RIDGE WILL BUILD
INTO WESTERN ALASKA TONIGHT THEN TRANSLATE EAST WITH TIME. THURSDAY
WILL BE THE DRIEST DAY FOR SOUTHCENTRAL WITH HIGH PRESSURE OVER THE
REGION; HOWEVER, ANOTHER STRONG SYSTEM WILL BRING ANOTHER ROUND OF
WIDESPREAD RAINFALL BEGINNING LATE THURSDAY AND FRIDAY.
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).
- PP/PA
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(DAYS 1 THROUGH 3: TONIGHT THROUGH SATURDAY MORNING)...
KEY MESSAGE: 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.
DISCUSSION:
AS OF THIS MORNING, WESTERLY WINDS IN THE WAKE OF YESTERDAY'S LOW
PRESSURE SYSTEM HAS ADVECTED IN THE MARINE LAYER FOR THE
SOUTHWEST ALASKA COASTLINE, YIELDING AREAS OF LOW STRATUS AND
PATCHY FOG FOR THE KUSKOKWIM DELTA AND BRISTOL BAY AREAS. ASIDE
FROM THAT, EXPECT RELATIVELY QUIET WEATHER FOR A ~24 HOUR PERIOD
AS TRANSIENT RIDGING SITUATES ITSELF ACROSS THE EASTERN ALEUTIANS,
ALASKA PENINSULA, AND EASTERN BERING. MEANWHILE, AN OCCLUDED LOW
PRESSURE SYSTEM IS MOVING NEAR THE WESTERN ALEUTIANS, GIVING
SHEMYA A ROUND OF HEAVY RAINFALL AND SOUTHERLY SMALL CRAFT WINDS
WITH GUSTS APPROACHING GALE FORCE. WHILE THE PARENT LOW MOVES
ALMOST DUE NORTH OF THE WESTERN ALEUTIANS, ITS FRONT IS PROGGED TO
TRAVERSE THE BERING AND ALEUTIANS THROUGH THE SHORT TERM FORECAST
PERIOD. NOT ONLY DOES THE FRONT STRENGTHEN INTO A GALE FORCE
FRONT THURSDAY MORNING, THERE WILL BE A PLETHORA OF MOISTURE
TRANSPORT FROM THE PACIFIC ASSOCIATED AS WELL RIDING UP AND ALONG
THE BOUNDARY, WHICH WILL MAKE THIS QUITE A WET SYSTEM AS IT
PROGRESSES EASTWARD. ONE THING MODELS ARE PICKING UP ON IS THE
LIKELIHOOD OF A SECONDARY AREA OF LOW PRESSURE FORMING IN RESPONSE
TO LOWERING PRESSURE AHEAD OF THE DIGGING UPPER LEVEL
TROUGH/CLOSED LOW TIED TO THE AFOREMENTIONED OCCLUDED SURFACE LOW,
WHICH COULD HELP TO ENHANCE RAINFALL AMOUNTS WITH THIS SYSTEM.
CONDITIONS DETERIORATE QUICKLY FOR THE PRIBILOF ISLANDS MID
THURSDAY MORNING AS SOUTHERLY SUSTAINED GALES APPROACH FROM THE
WEST, WITH WINDS GUSTING AS HIGH AS 55 MPH. THE GOOD NEWS FOR THE
PRIBILOF ISLANDS IS THAT THE AXIS OF STRONGEST WINDS WILL QUICKLY
MOVE IN AND OUT OF THE AREA AND WILL BEGIN DECREASING THURSDAY
AFTERNOON. FOR RAINFALL, THE PRIBILOFS ARE ON TRACK TO RECEIVE 1
TO 1.5 INCHES OF RAINFALL FROM THIS SYSTEM. BY LATE THURSDAY
MORNING TO THURSDAY AFTERNOON, RAIN AND WIND PUSHES EASTWARD, WITH
THE STRONGEST WINDS AGAIN LOOKING TO PUSH FROM KUSKOKWIM BAY
ACROSS THE DELTA BEFORE THIS CORE OF STRONG WINDS SHIFTS SOUTH AND
OVER BRISTOL BAY. ONE CHANGE IS THAT THE TRAILING WAVE LOOKS
STRONGER WITH A PERSISTENTLY STRONG SOUTHWESTERLY WIND FLOW
PUSHING BACK ACROSS KUSKOKWIM BAY AND DELTA INTO FRIDAY. THIS
CONTINUED PUSH OF WINDS WILL LIKELY RESULT IN HIGHER WAVES AND
ROUGH SEAS ALONG THE KUSKOKWIM BAY COAST, ESPECIALLY DURING HIGH
TIDE FRIDAY AFTERNOON. CURRENT PROBABILISTIC EXTRA-TROPICAL STORM
SURGE GUIDANCE SUGGESTS THAT WATER LEVELS WILL BE PUSHED 1.5 TO 2
FEET ABOVE THE NORMAL HIGH TIDE LINE FOR THE KUSKOKWIM BAY. ON THE
RAINY SIDE OF THINGS, SOUTHWEST ALASKA IS ON TRACK TO RECEIVE 1
TO 2 INCHES OF RAINFALL FROM THIS SYSTEM THROUGH FRIDAY AFTERNOON.
EXPECT CONTINUED SOUTHWESTERLY SMALL CRAFT WINDS FOR THE SOUTHERN
BERING AND BRISTOL BAY REGION INTO SATURDAY MORNING AS THE
HEAVIEST OF RAINFALL COMES TO AN END FOR SOUTHWEST ALASKA AND
CONDITIONS BECOME MORE SHOWERY IN NATURE. BY SATURDAY MORNING,
HIGH PRESSURE RETURNS TO THE BERING WITH GAP WINDS FOR THE ALASKA
PENINSULA RETURNING IN THE WAKE OF THIS SYSTEM.
-AM/TM
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...LIGHT WINDS AND VFR CONDITIONS ARE ANTICIPATED THROUGH THE
PREVAILING PERIOD. HOWEVER, LIGHT WINDS AND HIGH PRESSURE BUILDING
OVER THE REGION MAY ALLOW FOR POCKETS OF FOG TO DEVELOP NEAR THE
TERMINAL AROUND SUNRISE BOTH THIS MORNING AND THURSDAY MORNING.
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