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FXAK68 PAFC 111319
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
519 AM AKDT THU SEP 11 2025
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
RAIN...THAT ABOUT SUMS IT UP FOR SOUTHCENTRAL THE NEXT FEW DAYS.
AS FOR THE DETAILS: THE LOW, WHICH IS THE REMNANTS OF FORMER
TYPHOON PEIPAH, IS NOW JUST SOUTH OF THE KENAI PENINSULA WHERE IT
WILL GENERALLY SIT UNTIL FINALLY DISSIPATING ON SATURDAY. THE
FEATURE THAT HAS A LITTLE MORE UNCERTAINTY IS THE UPPER LEVEL
ARCTIC TROUGH THAT IS DIGGING INTO SOUTHWEST ALASKA AND EDGING
SLOWLY EASTWARD. THIS FEATURE CAN BE SEEN QUITE WELL ON GOES-18
SATELLITE IMAGERY AS THE NEARLY STRAIGHT NORTH-TO-SOUTH EDGE TO
THE CLOUDS THAT STRETCHES FROM THE ARCTIC COAST TO NEAR KING
SALMON. WITH COLD AIR FILTERING INTO SOUTHCENTRAL AND BEING
ENTRAINED INTO THE LOW, WINDS ARE INCREASING THROUGH THE KAMISHAK
GAP AND BRINGING GALE FORCE WINDS INTO THE BARREN ISLANDS AREA.
AS THE COLD AIR ALOFT MOVES IN, IT IS DESTABILIZING THE ATMOSPHERE
WHICH IS BRINGING A CHANCE FOR THUNDERSTORMS ALONG THE NORTH GULF
COAST AND INTO THE NORTHERN GULF FOR TODAY AND TONIGHT. THE OTHER
AREAS WITH A CHANCE FOR THUNDERSTORMS WILL BE IN THE NORTHEASTERN
COPPER BASIN THE NEXT FEW DAYS AS THERE WILL BE COLD AIR ALOFT
AND WITH A FEW BREAKS IN THE CLOUDS THERE, IT COULD KICK OF AN
ISOLATED THUNDERSTORM OR TWO. ONE OTHER QUESTION WITH THIS SYSTEM
IS EXACTLY HOW LOW FREEZING LEVELS WILL BE AS THEY LOWER OVER THE
NEXT FEW DAYS. THERE IS A SIGNIFICANT AMOUNT OF RANGE
(DISAGREEMENT) IN MODEL SOLUTIONS. THE GFS AND NBM ARE BOTH
KEEPING HIGHER FREEZING LEVELS AS COMPARED WITH THE NAM, GEM, AND
A NUMBER OF THE HI-RESOLUTION MODELS. PART OF THIS IS WITH THE GFS
BEING SLOWER TO MOVE THE COLD FRONT AND THE REST OF THE SYSTEM
THROUGH THE REGION, BUT IT IS A GENERALLY WARMER SOLUTION. AT THIS
TIME, IT LOOKS LIKE THERE IS STILL A CHANCE FOR SNOW TO REACH THE
MOUNTAINS DOWN TO ABOUT 4000 FT IN ANCHORAGE AND THE MATANUSKA
VALLEY REGIONS FRIDAY OR SATURDAY. AS ONE GOES NORTH IN THE
SUSITNA VALLEY, THERE IS A CHANCE OF SNOW MAKING IT DOWN TO CLOSER
TO ROAD LEVEL WITH BROAD PASS HAVING THE POTENTIAL FOR SNOWFALL
LATE TONIGHT AND FRIDAY NIGHT.
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(DAYS 1 THROUGH 3: TODAY THROUGH SATURDAY)...
MUCH OF THE OUTLOOK AREA NOW RESIDES WITHIN THE WESTERN ENVELOPE
OF A LONGWAVE TROUGH STRETCHING ACROSS ALASKA AND OUT OVER THE
BERING SEA. SEVERAL EMBEDDED SHORTWAVE TROUGHS ARE LEADING TO A
FEW LOCALIZED AREAS OF RAIN AND STRONGER WINDS. HOWEVER,
CONDITIONS BY AND LARGE ARE BECOMING CALMER COMPARED TO THE PAST
COUPLE DAYS, AS THE INFLUENCE FROM A WEAKENING LOW NOW DRIFTING
OVER THE GULF CONTINUES TO SLACKEN. WINDS REMAIN STRONG AND GUSTY
NEAR THE AKPEN, WHERE ENHANCED NORTHERLY FLOW BETWEEN THE LOW AND
A WEAK RIDGE IN THE CENTRAL BERING CONTINUES TO DRIVE THROUGH
FAVORED GAPS AND PASSES. A SMALL CORRIDOR OF GALE FORCE WINDS
CONTINUES TO STREAM OUT OF WIDE BAY TO THE EAST OF KODIAK ISLAND,
BUT SUSTAINED WINDS ALONG AND SOUTH OF THE REST OF THE AKPEN ARE
NOW BEGINNING TO DROP INTO SMALL CRAFT RANGE. TO THE NORTH ACROSS
SOUTHWEST, COLD AIR IS STREAMING IN FROM AN ARCTIC TROUGH SITUATED
OVER THE WESTERN MAINLAND, WITH TEMPERATURES NOW COMING DOWN INTO
THE 30S FOR A COUPLE SPOTS WHERE WINDS HAVE TEMPORARILY MANAGED
TO DROP OUT AT THE SURFACE. ACROSS THE CENTRAL ALEUTIANS, A WEAK
LOW SKIRTING TO THE SOUTH OF THE CHAIN IS SENDING A QUICK-HITTING
ROUND OF MODERATE RAIN ALONG THE CHAIN.
IN TERMS OF THE OUTLOOK THROUGH THE END OF THE WEEK, ONLY MILDLY
UNSETTLED AND VERY COOL CONDITIONS WILL DOMINATE THE PICTURE AS
WEAK FEATURES CONTINUE TO DRIFT WITHIN THE BROAD, DISORGANIZED
UPPER TROUGH IN PLACE. QUITE CHILLY CONDITIONS WILL RETURN TO
SOUTHWEST TONIGHT INTO FRIDAY MORNING AS NORTHWEST WINDS SHUT OFF,
ALLOWING IDEAL CONDITIONS FOR RADIATIONAL COOLING DOWN TO THE DEW
POINT WHERE SKIES ARE ABLE TO REMAIN MOSTLY CLEAR. A FREEZE/FROST
STILL LOOKS LIKELY TO AFFECT MUCH OF BRISTOL BAY AND THE LOWER
KUSKOKWIM VALLEY EARLY ON FRIDAY, WHILE AREAS CLOSER TO THE COAST
AND TOWARDS THE KUSKOKWIM DELTA MIGHT AVOID THE FREEZE THANKS TO
MORE PREVALENT CLOUD COVER. ACROSS THE ALASKA PENINSULA, WINDS
WILL HOLD ON A BIT LONGER, BUT CONTINUE TO WEAKEN TO 20 KTS OR
LESS BY FRIDAY MORNING.
MUCH OF THE SAME WILL PERSIST FRIDAY INTO SATURDAY. ANOTHER WEAK
LOW/TROUGH DRIFTING OVER THE WESTERN BERING COULD USHER A FEW
SHOWERS INTO THE CENTRAL ALEUTIANS AND PRIBILOFS, BUT CONDITIONS
WILL OTHERWISE REMAIN DRY AS WEAK AND DISORGANIZED FLOW PERSISTS.
MUCH OF SOUTHWEST WILL HAVE ANOTHER CHANCE AT A FREEZE FOR
SATURDAY MORNING, AGAIN DEPENDING MOSTLY ON WHERE SKIES STAY CLEAR
ENOUGH FOR EFFECTIVE RADIATIONAL COOLING BEFORE SUNRISE.
AS
LONG TERM FORECAST (SUNDAY THROUGH WEDNESDAY)
PERSISTENT LONGWAVE TROUGHING BROADLY STRETCHING FROM THE BERING
SEA TO SOUTHEAST ALASKA KEEPS BOTH THE SOUTHCENTRAL AND SOUTHWEST
REGIONS OF ALASKA ACTIVE THROUGH THE LONG TERM PERIOD. MODELS ARE
IN FAIRLY GOOD AGREEMENT TO BEGIN THE LONG TERM WITH A POTENT
SHORTWAVE LIFTING NORTH FROM THE BASE OF THE TROUGH INTO THE GULF
OF ALASKA. A LARGE 980-990 MB SURFACE LOW LOOKS TO PEAK IN
INTENSITY MONDAY MORNING AS IT ENTERS THE SOUTHWESTERN GULF. HEAVY
RAIN IS EXPECTED ALONG THE EASTERN KENAI PENINSULA AND NORTHERN
GULF COAST MONDAY INTO TUESDAY AS THE FRONTAL SYSTEM ARRIVES TO
THE COAST MONDAY MORNING. GUSTY NORTHERLY WINDS ACROSS THE ALASKA
PENINSULA ON THE BACKSIDE OF THE LOW AS WELL AS THE POTENTIAL
DEVELOPMENT OF A GALE-FORCE BARRIER JET OUTSIDE OF PRINCE WILLIAM
SOUND AHEAD OF THE FRONT WILL BE POSSIBLE SUNDAY THROUGH EARLY
NEXT WEEK. LIGHT TO MODERATE RAIN CONTINUES THROUGH THE END OF THE
FORECAST PERIOD ALONG THE GULF COAST WHILE SHOWERS SPREAD ACROSS
INLAND SOUTHCENTRAL FOR WEDNESDAY AS THE LOW PROGRESSES INLAND.
MULTIPLE ROUNDS OF SHORTWAVE ENERGY PROPAGATING FROM THE
KAMCHATKA REGION ACROSS THE BERING SEA WILL IMPACT PORTIONS OF THE
ALEUTIANS AND ALASKA PENINSULA MONDAY THROUGH THE END OF THE
FORECAST PERIOD. SOME UNCERTAINTY IN THE TRACK OF THE STRONGEST OF
THESE SYSTEMS FOR EARLY NEXT WEEK REMAINS AS MODELS SLOWLY COME
INTO AGREEMENT WITH THESE WEAKER FEATURES. ELEVATED WINDS AND
PERIODS OF RAIN MAY BE EXPECTED ACROSS MUCH OF THE ALEUTIANS AS A
LOW SKIRTS ALONG THE SOUTH OF THE ISLAND CHAIN AND ALASKA
PENINSULA THROUGH WEDNESDAY.
AVIATION
PANC...LIGHT AND VARIABLE WINDS WITH RAIN ARE FORECAST THROUGH
THE PERIOD AS AN UPPER TROUGH LINGERS SOUTH OF THE KENAI
PENINSULA. VFR TO MVFR CEILINGS ARE EXPECTED WITH PERIODS OF IFR
POSSIBLE THROUGH FRIDAY MORNING.
ER
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