379
FXAK68 PAFC 280035
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
435 PM AKDT TUE OCT 27 2026
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3/TONIGHT
THROUGH FRIDAY)...
A HIGH AMPLITUDE UPPER LEVEL RIDGE IS SITTING OVERHEAD OF
SOUTHCENTRAL. THIS LED TO AN IDEAL FOG SET-UP THIS MORNING, WITH
AREAS OF DENSE FOG FROM ANCHORAGE TO THE NW KENAI PENINSULA AND
DOWN TURNAGAIN ARM TO PORTAGE. SECONDARILY, THERE WAS ALSO SOME
FOG IN THE COPPER VALLEY. THE FOG HAS BEEN SLOWLY ERODING THROUGH
THE AFTERNOON HOURS, WITH ABUNDANT SUNSHINE ACROSS SOUTHCENTRAL
AND MUCH OF THE GULF AND KODIAK ISLAND. THERE WILL BE LITTLE
CHANGE IN CONDITIONS TONIGHT, SO THE MOST LIKELY SCENARIO IS A
REPEAT OF THIS MORNING, WITH AREAS OF DENSE FOG REDEVELOPING -
MOST LIKELY IN THE SAME GENERAL AREAS.
THE UPPER RIDGE WILL BE PUSHED SLOWLY EASTWARD TOWARD CANADA ON
WEDNESDAY THROUGH WEDNESDAY NIGHT AS A SHORT-WAVE TROUGH AND
SURFACE FRONTAL SYSTEM APPROACH FROM THE BERING SEA. THE MODELS
CONTINUE TO TREND SLOWER AND WEAKER WITH THESE FEATURES, WITH THE
UPPER LEVEL SHORT-WAVE LIFTING UP THE RIDGE TOWARD THE INTERIOR.
AS A RESULT, THE BULK OF PRECIPITATION WEDNESDAY NIGHT/THURSDAY
WILL BE FROM KODIAK TO THE WESTERN KENAI AND SUSITNA VALLEY, WITH
LIGHTER AND SHORTER DURATION OF PRECIPITATION FOR THE EASTERN
KENAI, ANCHORAGE, AND MAT VALLEY.
WHILE THE UPPER SHORT-WAVE EXITS NORTHWARD ON THURSDAY AND THE
SURFACE FRONT DISSIPATES, SOUTHERLY UPSLOPE FLOW WILL STRENGTHEN
OUT AHEAD OF THE NEXT BERING SEA STORM. THIS WILL LEAD TO
INCREASING PRECIPITATION RATES ALONG THE SOUTHEASTERN KODIAK
ISLAND, SOUTHERN KENAI PENINSULA, AND WESTERN TO NORTHERN SUSITNA
VALLEY. WHILE PRECIPITATION TYPE WILL MAINLY BE IN THE FORM OF
RAIN, WILL NEED TO KEEP AN EYE ON THE NORTHERN TO WESTERN SUSITNA
VALLEY, WHERE CONDITIONS WILL INITIALLY BE COLD ENOUGH FOR SNOW.
A STRONG FRONT (AND ACCOMPANYING ATMOSPHERIC RIVER ALOFT) WILL
THEN ARRIVE FROM THE BERING THURSDAY NIGHT AND SLOWLY MARCH
EASTWARD THROUGH FRIDAY. WHILE THERE IS SOME UNCERTAINTY IN TIMING
OF THE FRONT, CONFIDENCE IS HIGH (80%) IN HEAVY RAIN FOR COASTAL
AREAS AND THE COOK INLET TO SUSITNA VALLEY CORRIDOR, WITH SNOW
LEVEL RISING TO 2000 (SUSITNA VALLEY) TO 3500 FEET (KENAI
PENINSULA AND PRINCE WILLIAM SOUND) BY FRIDAY AFTERNOON. AS IS
TYPICAL WITH A STRONG FRONT, SOUTHEASTERLY GAP WINDS WILL DEVELOP
AHEAD OF THE FRONT, INCLUDING TURNAGAIN ARM AND THE COPPER RIVER
VALLEY. WHILE THERE WILL BE SOME LOW LEVEL DOWNSLOPE FLOW, ANY
DRYING WILL BE OVERCOME BY VERY MOIST SOUTHERLY FLOW AND STRONG
UPWARD VERTICAL MOTION ALOFT.
-SEB
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3)...
A BERING FRONT IS GENERATING A SWATH OF LOW STRATUS AND FOG TO
THE PRIBILOF ISLANDS AND MUCH OF THE ALEUTIAN ISLANDS THIS
AFTERNOON. A PERIOD OF RAIN AND GALE FORCE WINDS ASSOCIATED WITH
THE FRONT ARE EXPECTED TO PUSH EAST OVERNIGHT AND INTO THE COAST
OF SOUTHWEST ALASKA. A STRONG RIDGE OVER MAINLAND ALASKA WILL
STALL THE FRONT OVER COASTAL SOUTHWEST AND THE ALASKA PENINSULA
WEDNESDAY MORNING. AN EXCEPTION IS THE KUSKOKWIM DELTA, WHICH WILL
SEE CONTINUED GUSTY SOUTH TO SOUTHWESTERLY WINDS AS HIGH AS 55
MPH TONIGHT INTO TOMORROW MORNING. THE STRONGER WINDS WILL BE
DRIVEN BY A SHORTWAVE TROUGH LIFTING ALONG AND REINFORCING THE
FRONT OVER THE REGION. DUE TO THE PERSISTENT SOUTHERLY FLOW AND
HIGHER TIDES, ELEVATED WATER LEVELS (1 TO 2 FEET ABOVE THE NORMAL
HIGHEST TIDE LINE) ARE EXPECTED ALONG THE KUSKOKWIM COAST. A HIGH
SURF ADVISORY REMAINS IN EFFECT THROUGH 10 AM ON WEDNESDAY MORNING
WHILE A WIND ADVISORY IS IN EFFECT FOR THE KUSKOKWIM DELTA FROM
10 PM TONIGHT THROUGH 10 AM TOMORROW.
BY THE END OF THE WEEK, A LARGE LOW ASSOCIATED WITH THE REMNANTS
OF EX-TYPHOON CHAMPI MOVES INTO THE BERING. THIS LOW HAS A HIGH
LIKELIHOOD OF BRINGING STORM FORCE AND GALE FORCE WINDS TO THE
ALEUTIANS, AS WELL AS CONTINUED SOUTH TO SOUTHWEST FLOW TO THE
KUSKOKWIM DELTA BOTH THURSDAY AND FRIDAY. THE TIDE CYCLE WILL PEAK
THROUGH THE END OF THE WEEK RESULTING IN HIGHER WATER LEVELS FOR
THE KUSKOKWIM DELTA COAST, ESPECIALLY ON FRIDAY. WHILE EXACT WATER
LEVELS ARE STILL BEING DETERMINED, CURRENT THINKING IS FOR
POTENTIAL WATER LEVELS BETWEEN 1 AND 3 FT ABOVE THE NORMAL HIGHEST
TIDE LINE FOR KIPNUK AND KWIGILLINGOK. STAY TUNED FOR ANY UPDATES
AS THE TRACK OF THE LOW COULD CHANGE.
-SS
.LONG TERM FORECAST (DAYS 4 THROUGH 7: SATURDAY THROUGH
TUESDAY)...
VERY LITTLE CHANGE FROM THE PREVIOUS LONG TERM DISCUSSION. THE
LONG TERM LOOKS TO BE REMAIN ACTIVE, PARTICULARLY FOR THE BERING
SEA, ALEUTIAN CHAIN, AND SOUTHWEST ALASKA LOCATIONS. BY SATURDAY,
THE GLOBAL MODELS ARE IN FAIRLY GOOD AGREEMENT AND DEPICT EX-
TYPHOON CHAMPI MERGING WITH ANOTHER STRONG LOW PRESSURE SYSTEM AND
BECOMING A LARGE, DEEP, AND OCCLUDED LOW PRESSURE SYSTEM MOVING
EASTWARD ACROSS THE BERING (AND WEAKENING AS IT DOES SO) WITH ITS
FRONT QUICKLY ENTERING THE GULF OF ALASKA ON SATURDAY. AS THE
FRONT NEARS THE GULF COAST, EXPECT COASTAL RIDGING AND A RETURN OF
GAP WINDS FOR SOUTHCENTRAL FOR THE TURNAGAIN ARM, KNIK RIVER
VALLEY, AND COPPER RIVER BASIN FOR THE WEEKEND, POSSIBLY LINGERING
INTO THE FIRST PART OF NEXT WEEK. AS MENTIONED, THE SURFACE LOW
WILL BE WEAKENING AS IT MOVES INLAND INTO SOUTHWEST ALASKA, WITH
STRONG NORTHWESTERLY GAP WINDS BECOMING A COMMON THEME FOR THE
CENTRAL AND EASTERN ALEUTIANS BY SATURDAY MORNING. PATTERN
RECOGNITION SUGGESTS THAT ONE PLACE TO WATCH WILL BE COLD BAY, AS
NORTHWEST WINDS CAN BE ESPECIALLY ENHANCED THROUGH THE GAP THERE.
EXPECT GAP WINDS ELSEWHERE TO BE ELEVATED, BUT GENERALLY
DECREASING IN INTENSITY THROUGH THE FAVORED BAYS AND PASSES OF THE
ALASKA PENINSULA THROUGH SUNDAY MORNING.
MODELS ARE IN SOMEWHAT BETTER AGREEMENT TODAY REGARDING A
SECONDARY LOW PRESSURE SYSTEM SITUATED OFF THE KAMCHATKA PENINSULA
AND MOVING INTO THE BERING LATE SUNDAY INTO EARLY MONDAY MORNING.
THOUGH THERE IS A BETTER CONSENSUS TODAY THAN YESTERDAY, THERE IS
STILL QUITE A BIT OF SPREAD ON THIS SYSTEM AS THE GFS REMAINS THE
MUCH MORE BULLISH/STRONGER SOLUTION WHILE OTHER MODEL GUIDANCE
CONTINUES TO STRUGGLE RESOLVING THIS SYSTEM IN TERMS OF INTENSITY
AND POSITIONING. 850 MB TEMPERATURE ANOMALIES SUGGEST THAT
TEMPERATURES STAY AT OR ABOVE AVERAGE THROUGH THE END OF THE LONG
TERM FOR THE BOTH THE WEST AND EAST.
-AM
AVIATION
PANC...MOSTLY VFR CONDITIONS AND LIGHT WINDS WILL PERSIST UNTIL
LATE THIS EVENING. FOG IS LIKELY TO REDEVELOP OVERNIGHT, BRINGING
CONDITIONS DOWN TO IFR-LIFR. SIMILAR TO TODAY, FOG IS EXPECTED TO
LIFT BY THE LATE MORNING TO EARLY AFTERNOON HOURS TOMORROW. LATE
IN THE TAF PERIOD, THERE IS A THREAT FOR MARGINAL LLWS AS
SOUTHEAST WINDS BEGIN TO INCREASE ALOFT AHEAD OF AN INCOMING
FRONTAL SYSTEM. HOWEVER, THE CONFIDENCE FOR LLWS TO DEVELOP BY THE
AFTERNOON TOMORROW REMAINS FAIRLY LOW, AS IT APPEARS SOME MODEL
SOLUTIONS COULD BE OVERDOING THE INTENSITY FOR THE INITIAL PUSH OF
LOW LEVEL SOUTHEASTERLY WINDS.
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