899
FXAK67 PAJK 040534
AFDAJK
SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
934 PM AKDT SAT OCT 3 2026
SYNOPSIS
KEY MESSAGES:
- STRONG WINDS AND HIGHEST RAIN ACCUMULATIONS ANTICIPATED TO PEAK
OVERNIGHT SATURDAY. HEAVY RAINFALL AT HIGHER ELEVATIONS CAN
CAUSE SMALLER CREEKS AND STREAMS TO RISE RAPIDLY THROUGH SUNDAY
MORNING.
- UNSTABLE AIR BEHIND THE MAIN FRONT BRINGS A RISK OF ISOLATED
THUNDERSTORMS ON SUNDAY ALONG THE NORTHEAST GULF COAST.
- UNSETTLED CONDITIONS ARE EXPECTED TO PERSIST INTO EARLY NEXT
WEEK AS MULTIPLE FRONTS BRING OCCASIONAL BREEZY WINDS AND
HEAVIER SHOWERS.
SHORT TERM.../THROUGH SUNDAY NIGHT/
SMALL CHANGES TO THE
ONGOING FORECAST, WITH LITTLE CHANGE IN MESSAGE. LOOKING TO
SATELLITE, A STRONG WARM CONVEYER BELT IS SURGING OVER THE
PANHANDLE. WHILE THIS HAS NOT TRANSLATED TO SIGNIFICANT RAINFALL,
IT IS SETTING THE STAGE FOR MODERATE TO HEAVY RAINFALL FOR
TONIGHT. THE FRONT, CURRENTLY OFFSHORE, IS EXPECTED TO MOVE OVER
THE CENTRAL AND SOUTHERN PANHANDLE IN THE FOLLOWING HOURS. FOR
MORE INFORMATION REGARDING HYDROLOGY AND FLOODING POTENTIAL, SEE
THE HYDROLOGY SECTION.
AS THE FRONT MOVES INTO CANADA, THE UPPER LEVEL LOW IS ABSORBED
SOMEWHAT INTO THE FLOW FROM THE STRONGER UPPER LEVEL LOW NEAR THE
ALEUTIAN CHAIN. IN ITS WAKE, ANOTHER, COLDER SHORTWAVE TROUGH
SWINGS ACROSS THE NORTHERN GULF, INCREASING LAPSE RATES AND
BRINGING SOME CAPE INTO THE EQUATION. SIMILAR TO YESTERDAY, THIS
CAPE DOES NOT LOOK TOO IMPRESSIVE, MAXIMIZING AROUND 200-400 J/KG,
COULD SEE SOME SLIGHTLY LONGER LASTING STORMS ALONG THE NE GULF
COAST WITH BULK SHEAR VALUES AROUND 30 KNOTS FROM THE SOUTHWEST
AND LIS OF AROUND -2. THEREFORE, THREW IN SOME ISOLATED
THUNDERSTORMS FOR THE NE GULF COAST ON SUNDAY AS THE HIGHEST
CHANCE, WITH SHOWERS EXTENDING DOWN TO SITKA. MODERATE TO HEAVY
RAIN COULD BE ASSOCIATED WITH THESE SHOWERS. HIGHEST CHANCE FOR
THESE MORE WIDESPREAD SHOWERS ARE SUNDAY AFTERNOON.
LONG TERM.../TUESDAY THROUGH THURSDAY/
UNSETTLED WEATHER WILL
CONTINUE INTO AT LEAST THE BEGINNING OF THIS PERIOD AS LOW
PRESSURE MEANDERS WHILE SLOWLY WEAKENING OVER SOUTH-CENTRAL
ALASKA. THE HEAVIEST RAINFALL TUESDAY INTO EARLY WEDNESDAY WILL
LIKELY BE CENTERED OVER THE NORTHEAST GULF COAST AND NORTHERN
PANHANDLE WITH LIGHTER AMOUNTS FARTHER SOUTH. A FEW THUNDERSTORMS
STILL ALSO APPEAR POSSIBLE, ESPECIALLY OVER THE COASTAL WATERS,
BUT WE DID NOT INCLUDE THUNDER IN THE FORECAST AT THIS TIME GIVEN
THE UNCERTAINTY AND ANTICIPATED LOW COVERAGE. AS THE
AFOREMENTIONED LOW FINALLY DISINTEGRATES ON THURSDAY, WE SHOULD
SEE AN OVERALL IMPROVEMENT IN CONDITIONS. A SEPARATE, MORE INTENSE
LOW PRESSURE SYSTEM MAY APPROACH THE SOUTHERN PANHANDLE LATE
THURSDAY AND BEYOND, BUT MODEL AGREEMENT ON THE TRACK AND TIMING
OF THE SYSTEM IS QUITE LOW. THIS WILL BE MONITORED CLOSELY IN
FUTURE FORECASTS. AFTER THIS POTENTIAL SYSTEM, HIGH PRESSURE WILL
ATTEMPT TO AT LEAST BRIEFLY BUILD INTO THE GULF.
AVIATION.../THROUGH 06Z MONDAY/
A FRONT BEING PUSHED IN TO THE PANHANDLE
THIS EVENING, AND IS BRINGING MVFR CEILINGS AND VISIBILITIES.
WITH HEAVIER SHOWERS, IFR CONDITIONS APPEAR TO BE POSSIBLE TONIGHT.
SO FAR, THE HIGHEST RAINFALL RATES HAVE BEEN ALONG THE GULF COAST
AND NORTHERN PANHANDLE. WITH 35-45 KT WINDS 2000 FEET AGL, THIS
WILL LEAD TO LOW-LEVEL WIND SHEAR CONCERNS. HOWEVER, AS THE FRONT
DIMINISHES, SO WILL THE THREAT FOR LOW-LEVEL WIND SHEAR. THE WINDS
ARE EXPECTED TO DIMINISH ACROSS THE AREA FROM NORTH TO SOUTH.
BEFORE ANOTHER ROUND OF RAIN AFTER 21Z SUNDAY, A BRIEF TIME OF
HIGH-END MVFR/VFR APPEARS POSSIBLE, BUT NOT A GUARANTEE.
BEHIND THE FRONT IMPACTING THE AREA AT THE TIME OF WRITING, A LOW
IN THE BERING SEA WILL PUSH ANOTHER ROUND OF RAIN TOWARD THE
NORTHERN PANHANDLE SUNDAY EVENING. THIS WILL LIKELY BRING MVFR
CEILINGS/VISIBILITIES TO SOUTHEAST ALASKA. WITH COLD AIR ALOFT,
THIS MAY LEAD TO SOME THUNDERSTORM DEVELOPMENT, BUT CONFIDENCE IN
THIS OCCURRING WAS TOO LOW TO INCLUDE IN THIS AVIATION UPDATE.
OVERALL, THE SYSTEM IN THE BERING SEA IS EXPECTED TO WEAKEN AS IT
MOVES EAST INTO THE GULF OF ALASKA. SOME OF THE STRONGER WINDS
ALOFT ASSOCIATED WITH THE SYSTEM ALOFT MAY TRY TO IMPACT KLAWOCK
AND KETCHIKAN TOWARD THE END OF THE TAF PERIOD. HOWEVER, THE
STRONGEST WINDS LOOK TO REMAIN SOUTH OF THE PANHANDLE.
MARINE
OUTSIDE:
CONDITIONS WILL CONTINUE TO DETERIORATE SATURDAY AFTERNOON AS A
GALE FORCE LOW AND ASSORTMENT OF FRONTS MOVES INTO THE COAST. AS
OF THIS WRITING AT 1400 AKDT SATURDAY, CAPE ST. ELIAS IS REPORTING
GALES FROM A BARRIER JET, WITH 18 FT FRESH SEAS. ASCAT WINDS
(SATELLITE DERIVED WINDS) FROM SATURDAY MORNING CONTINUE TO MATCH
HIGH RESOLUTION GUIDANCE WELL. AS A FRONT APPROACHES THE COAST
THIS EVENING EXPECT SOUTHERLY 35 TO 45 KNOT SUSTAINED WINDS AND
SEAS BUILDING TO 15 TO 20 FT FOR MUCH OF OUR COAST. THE HEAVIEST
CONDITIONS WILL BE FROM CAPE EDGECUMBE TO CAPE ST. ELIAS; HOWEVER,
THE COAST OF PRINCE OF WALES WILL CERTAINLY SEE NEAR-GALE TO GALE
FORCE CONDITIONS.
AS THE FRONT MOVES OFF INTO THE PANHANDLE SUNDAY, EXPECTING ESE
WINDS TO PERSIST ALONG THE NORTHERN COAST, WITH SOUTHERLY WINDS
BECOMING SOUTHWEST ALONG THE COAST OF THE ALEXANDER ARCHIPELAGO.
WINDS WILL VARY FROM MODERATE TO FRESH BREEZES. ONE COMPONENT IS A
LARGE INFLUX OF SOUTHWEST WAVE ENERGY, DRIVING FRESH SEAS WITH
SIGNIFICANT HEIGHTS NEAR 9 TO 12 FT. CONDITIONS LIKELY IMPROVE
WEDNESDAY BRINGING A SHORT BREAK BEFORE ANOTHER LARGE SYSTEM MOVES
INTO THE GULF.
INSIDE:
NOT A GREAT NIGHT TO BE MOVING AROUND ON A SMALL BOAT IN THE
INNER CHANNELS. MAKE READY FOR A STRONG FRONT SATURDAY NIGHT INTO
SUNDAY. EXPECTING THE FRONT TO REACH CROSS SOUND AND SITKA NEAR
5PM TO 7PM, QUICKLY MOVING NORTHEAST THROUGH THE INNER CHANNELS
OVERNIGHT. BY AND LARGE SUSTAINED WINDS WILL BE ESE STRONG BREEZES
FOR THE AREA, WITH AREAS OF NEAR-GALE TO GALE FORCE. CURRENT
FORECAST FAVORS SUMNER STRAIT, SOUTHERN CHATHAM, AND NORTHERN
CLARENCE STRAIT TO SEE NEAR-GALE TO GALES AS THE FRONT MOVES OVER.
AT FIRST, ESE WINDS WILL FLOW FROM CLARENCE UP THE INSIDE, WITH
EASTERLY WINDS OUT OF TAKU, ICY STRAIT, AND CROSS SOUND, WITH
SOUTHERLY WINDS BUILDING AFTER THE FRONT, MOVING UP LYNN CANAL AND
GLACIER BAY.
HYDROLOGY
A STRONGER SYSTEM IS EXPECTED TO MOVE INTO THE PANHANDLE SATURDAY
INTO SUNDAY, BRINGING PERIODS OF MODERATE TO HEAVY RAIN. MAIN
CHANGES TO THE ONGOING FORECAST IS AN INCREASE TO EXPECTED
ACCUMULATIONS IN THE SOUTHERN PANHANDLE BY UP TO HALF AN INCH.
COMPARED TO THE PREVIOUS FORECAST, THAT STILL PUTS MOST AREAS
BETWEEN THE 1.5 - 3.0 INCH MARK. FURTHERMORE, HIGHER RAINFALLS ARE
MOST LIKELY ON SOUTH TO SOUTHWEST FACING MOUNTAIN FACES. DURING
THE PEAK OF HEAVIER RAINFALL DURING THE OVERNIGHT HOURS, RAIN
RATES COULD EXCEED 0.15 INCHES PER HOUR IN THE CENTRAL PANHANDLE
AND 0.25 INCHES PER HOUR IN THE SOUTHERN PANHANDLE. MODERATE TO
HEAVY RATES ARE EXPECTED TO CONTINUE FOR ANY GIVEN LOCATION FOR A
PERIOD OF AROUND 12-18 HOURS BEFORE DECREASING. UPWARDS OF 4
INCHES WILL BE POSSIBLE FOR HIGHER ELEVATIONS. DUE TO THE SHORT
NATURE OF THE HEAVIER RAINFALL, SMALLER CREEKS AND STREAMS WILL
RISE QUICKLY, MAY POSSIBLY REACH BANKFULL CONDITIONS, BUT ARE NOT
EXPECTED TO FLOOD AT THIS TIME.
AJK WATCHES/WARNINGS/ADVISORIES
PUBLIC...WIND ADVISORY UNTIL 10 AM AKDT SUNDAY FOR AKZ323-327-328-332.
MARINE...GALE WARNING FOR PKZ036-641>644-651-652-661>664-671-672.
SMALL CRAFT ADVISORY FOR PKZ011>013-021-022-031>035-053.
SHORT TERM...NC
LONG TERM...MJB
AVIATION...MUSALL
MARINE...AP
HYDROLOGY...NC
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