901
FXAK67 PAJK 190457
AFDAJK
SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
857 PM AKDT SUN OCT 18 2026
UPDATE...UPDATE FOR THE LONG TERM AND 06Z TAF ISSUANCE
WEAK ONSHORE FLOW ALONG WITH SUBTLE WAVE WILL KEEP MAINLY CLOUDY
SKIES AND LIGHT SHOWERS FROM SITKA ON UP THROUGH THE NORTHERN
PANHANDLE TONIGHT. SOUTH OF THERE, CLEARING THIS EVENING HAS
ALLOWED FOR FOG AND LOW STRATUS TO DEVELOP AT ANGOON, KLAWOCK AND
PETERSBURG. EXPECT THE FOG/LOW STRATUS TO EXPAND OVERNIGHT AND
HAVE INCREASED FOG COVERAGE OVERNIGHT FROM FREDERICK SOUND ON
SOUTH.
SYNOPSIS
KEY MESSAGES:
- A BRIEF BREAK IN THE RAIN IS POSSIBLE SUNDAY NIGHT INTO MONDAY,
HOWEVER ANOTHER FRONT AND ROUND OF HEAVY RAIN AND STRONG WINDS
PUSH ACROSS THE GULF OF ALASKA INTO THE ALASKA PANHANDLE BY
MONDAY NIGHT AND CONTINUES THROUGH TUESDAY.
- FLOOD WATCH ISSUED FOR YAKUTAT, GUSTAVUS, PELICAN, AND ELFIN
COVE, AND JUNEAU. ISOLATED LANDSLIDES POSSIBLE ALONG THE NE
GULF COAST, AND GLACIER BAY, NEAR STEEP TERRAIN.
- MARITIME INTERESTS NEED TO PAY ATTENTION TO THE STRONG FRONT
PROJECTED TO MOVE ACROSS THE GULF OF ALASKA BY MONDAY AFTERNOON,
BRINGING GALE FORCE TO POTENTIALLY STORM FORCE WINDS TO THE
CENTRAL AND EASTERN GULF TUESDAY INTO WEDNESDAY.
SHORT TERM.../THROUGH TUESDAY NIGHT/
A STRONG SYSTEM IS EXPECTED TO MOVE INTO THE NORTHERN CENTRAL
GULF, REINFORCING THE EXISTING LOW PRESSURE SYSTEM, AND DRAWING A
DEEPER FETCH OF MOISTURE FROM NORTHERN PACIFIC. BY TUESDAY
MORNING, THIS PLUME OF MOISTURE IS EXPECTED TO SHIFT FROM
SOUTHWEST TO SOUTHERLY, AND IS LIKELY TO EXCEED 600 KG/MS IVT FOR
AROUND A 12-18 HOUR PERIOD FOR ANY GIVEN LOCATION IN THE ICY
STRAIT CORRIDOR AND NE GULF COAST. EXPECTING YAKUTAT TO BE THE BIG
WINNER IN TERMS OF RAIN AMOUNTS, WITH NEAR PERFECT PERPENDICULAR
FLOW, STRONG WAA IN THE LOW LEVELS INCREASING LIFT POTENTIAL, AND
DECENT DIVERGENCE ALOFT. WITH THIS, YAKUTAT COULD SEE UPWARDS OF 6
INCHES DURING A 36 HOUR PERIOD, WHICH IS A LITTLE HIGHER THAN A 2
YEAR ARI EVENT. THERE ARE LOWER PROBABILITIES OF AROUND 30% TO
SEE A 5 YEAR EVENT FOR 36 HOURS FOR THE NE GULF COAST, AND EVEN
HIGHER ARIS ARE POSSIBLE FURTHER INTO YAKUTAT BAY. THESE HIGHER
ARIS LOOK TO EXTEND DOWN THE COAST AND INTO THE GLACIER BAY AREA,
WITH MAY AREAS ALONG SOUTH FACING SLOPES EXCEEDING 5 YEAR RETURN
INTERVALS AND APPROACHING ON 10 YEAR OVER A 36 HOUR PERIOD.
THEREFORE, ADDED ELFIN COVE, SPECIFICALLY FOR THE MOUNTAINS TO THE
NORTH, THE NE GULF COAST, AND GLACIER BAY TO THE FLOOD WATCH.
THIS IS MAINLY FOR AREAL FLOODING OF LOW LYING AREAS AND PONDING
OF WATER. THAT BEING SAID, THE WIND COMPONENT OF THIS SYSTEM HAS
WIND GUSTS GREATER THAN 40 MPH AT ELEVATIONS GREATER THAN 500 FT,
AND GREATER THAN 60 MPH AT ELEVATIONS AROUND 2000 FT. CURRENT
THINKING IS THE HIGH RAIN RATES COMBINED WITH HIGHER RETURN
INTERVALS IN THE UPPER RAINFALL RANGES (HIGHER PERCENTILES, LOWER
PROBABILITY) LEADS TO AN INCREASED RISK OF ISOLATED LANDSLIDES IN
STEEP TERRAIN BASED ON HISTORICAL ATMOSPHERIC CONDITIONS.
LONG TERM.../WEDNESDAY THROUGH SATURDAY/
THE FRONT THAT BROUGHT HEAVY RAIN AND STRONG WINDS ON TUESDAY WILL
HAVE ALL BUT CLEARED THE SOUTHERN PANHANDLE BY DAYBREAK
WEDNESDAY. IN ITS WAKE, PERSISTENT ONSHORE FLOW WILL CONTINUE
THROUGH WEDNESDAY AND INTO THURSDAY AS THE LOW LINGERS AND SLOWLY
WEAKENS IN THE NORTHERN GULF OF ALASKA. SUBTLE SHORTWAVES AND
UPPER TROUGHS SWINGING AROUND THIS LOW WILL KEEP HIGHER
PRECIPITATION CHANCES WITH MODERATE TO HEAVY SHOWERS AND GUSTY
WINDS ACROSS SEAK THROUGH THURSDAY. BEHIND THE FRONT, SNOW LEVELS
FALL TO 1,000–2,000 FT ON WEDNESDAY OVER THE NORTHERN PANHANDLE.
SNOW SHOWERS WILL BE POSSIBLE ALONG THE KLONDIKE HIGHWAY AND UPPER
REACHES OF THE HAINES HIGHWAY THROUGH THURSDAY, THOUGH ANY
ACCUMULATION WILL REMAIN LIGHT. AS THE LOW WEAKENS AND GRADIENT
RELAXES BEHIND THE FRONTAL PASSAGE, GUSTY SOUTHERLY WINDS WILL
SLOWLY DIMINISH THROUGH THURSDAY. THE NORTHERN INNER CHANNELS AND
INTO HAINES AND SKAGWAY COULD STILL BE QUITE GUSTY ON WEDNESDAY
AS THE NORTH TO SOUTH GRADIENT REMAINS A BIT TIGHTER, AND THE HIGH
WIND WATCH REMAINS IN EFFECT OF SKAGWAY. AS THE GULF LOW WEAKENS
FURTHER AND SHIFTS SOUTHEAST TOWARD THE END OF THE WEEK, SHOWERS
WILL LIGHTEN AND END FROM NORTH TO SOUTH THURSDAY NIGHT INTO
FRIDAY ACROSS SEAK. UPPER-LEVEL RIDGING MAKES BUILDS EAST ACROSS
MAINLAND ALASKA BY LATE WEEK, WITH SEAK ON THE EASTERN EDGE OF THE
RIDGE. ENSEMBLE AND DETERMINISTIC GUIDANCE GENERALLY SHOWING HIGH
PRESSURE BUILDING IN THE WAKE OF THE DEPARTING LOW, WITH CLEARING
SKIES AND DRIER OFFSHORE FLOW DEVELOPING FRIDAY AND CONTINUING
INTO THE EARLY WEEKEND. DAYTIME HIGHS WILL REMAIN IN THE 40S
THROUGHOUT THE PERIOD, WITH OVERNIGHT LOWS IN THE MID 30S TO LOW
40S.
AVIATION.../THROUGH 06Z TUESDAY/
VFR CONDITIONS PREVAIL ACROSS
MOST OF THE PANHANDLE. A WIDESPREAD CLOUD SHIELD HAS MOSTLY
CLEARED THE SOUTHERN REGION, IMPROVING CLOUD DECKS FROM OVC/BKN TO
SCT/FEW. HOWEVER, THIS CLEARING HAS BROUGHT ALMOST IMMEDIATE FOG
FORMATION, AIDED BY SATURATED LOWER LEVELS AND CALMING WINDS. THIS
IS EXPECTED TO SIGNIFICANTLY REDUCE VSBY TO 1-2 SM THROUGH THE
EARLY MORNING, IMPACTING SITES FROM FREDERICK SOUND SOUTHWARD,
THOUGH ALSO INCLUDING SOUTHERN PARTS OF ADMIRALTY ISLAND.
MEANWHILE, THE NORTHERN PANHANDLE WILL REMAIN IN A LIGHTER, SHOWERY
REGIME TONIGHT, AHEAD OF THE SYSTEM TOMORROW. SEVERAL SITES, MOST
NOTABLY PAJN, PAGS, AND PAHN, SEEING FLIGHT CATEGORIES SHIFT TO MVFR
THIS EVENING. CIGS EXPECTED TO SIT BETWEEN 2000-3000FT, THEN
SHIFTING DOWN TO 1500-2500FT BY THE AFTERNOON.
FINALLY, LLWS IS LIKELY NEAR PAYA STARTING MONDAY AFTERNOON INTO
EVENING AS THE NEXT SYSTEM MOVES FURTHER EAST INTO THE GULF. THIS IS
DRIVEN BY A STOUT LOWER LEVEL JET OF 45-50 KT WINDS THAT WILL PUSH
THE SYSTEM TOWARD THE NORTHERN GULF COAST AND BRING HEAVY RAIN AND
STRONG WINDS ACROSS THE ENTIRE PANHANDLE BY TUESDAY MORNING, FURTHER
DETERIORATING CONDITIONS.
MARINE
OUTSIDE (GULF AND COASTAL WATERS): LINGERING WESTERLY MODERATE TO
FRESH BREEZES WILL CONTINUE TO PUSH EASTWARD AND DIMINISH SUNDAY
NIGHT AS A BRIEF AREA OF RIDGING MOVES ACROSS THE GULF. CONDITIONS
WILL QUICKLY DETERIORATE FROM WEST TO EAST ACROSS THE GULF MONDAY
MORNING AS A STRONG SYSTEM SENDS A STRONG GALE FORCE FRONT
TOWARDS THE PANHANDLE INTO TUESDAY. WITH THE INITIAL SYSTEM ON
MONDAY, SOUTHERLY WINDS IN THE CENTRAL GULF WILL INCREASE TO GALE
FORCE WITH MUCH OF THE COAST SEEING STRONG BREEZES TO NEAR GALE
FORCE WINDS. A BARRIER JET ALSO LOOKS TO FORM ALONG THE NORTHERN
GULF COAST FROM KAYAK ISLAND EASTWARD TO ICY BAY WITH THIS FIRST
SYSTEM, BRINGING EAST TO SOUTHEASTERLY STRONG GALE FORCE WINDS
INTO TUESDAY. SOME GUIDANCE IS INDICATING POTENTIAL FOR THIS TO
REACH STORM FORCE LATE MONDAY NIGHT, BUT CURRENT THINKING IS
CAPPED AT 46 KTS. ANOTHER SYSTEM LOOKS TO RACE UP THE WESTERN GULF
COAST OVERNIGHT INTO TUESDAY, STRENGTHENING THE INITIAL SYSTEM
AND SENDING ANOTHER STRONG FRONT INTO THE PANHANDLE TUESDAY INTO
WEDNESDAY. WIDESPREAD SOUTHERLY 35 TO 45 KT WINDS ARE EXPECTED TO
TAKE OVER THROUGH THE REMAINDER OF THE GULF AND ALONG MUCH OF THE
COAST TUESDAY, WHICH SHOULD STEADILY DECREASE THROUGH WEDNESDAY.
STRONG SOUTHWESTERLY SWELL IS ALSO EXPECTED TO INCREASE, WITH THE
FIRST SYSTEM BRINGING 10 TO 13 FT AT A PERIOD OF 10 TO 12 SECONDS
MONDAY AND THE SECOND SYSTEM QUICKLY INCREASING TO 20 TO 25 FT AT
A PERIOD OF 13 TO 15 SECONDS. THIS WILL BRING ACCENTUATED WAVE
HEIGHTS OF 16 TO 19 FT BY MONDAY NIGHT AND 25 TO 28 FT THROUGH
TUESDAY. THIS WILL MAINLY BE AN ISSUE FOR THE NORTHERN AND CENTRAL
PARTS OF THE GULF, WITH AREAS NEAR DIXON ENTRANCE STAYING CLOSER
TO 12 TO 18 FT AT MOST.
INSIDE (INNER CHANNELS): DIMINISHING WIND SPEEDS WILL BE THE
TREND FROM NOW THROUGH SUNDAY NIGHT BEFORE ANOTHER STRONG SYSTEM
MOVES INTO THE GULF MONDAY. NORTHERN LYNN CANAL AND NORTHERN
STEPHENS PASSAGE ARE THE ONLY PARTS OF THE CHANNELS STILL SEEING
10 TO 15 KTS OF SOUTHERLY WINDS, WHILE THE REST OF THE PANHANDLE
IS MOSTLY LIGHT. FOG DEVELOPMENT WILL BE POSSIBLE THROUGH EARLY
MONDAY MORNING, MAINLY FOR THE SOUTHERN PANHANDLE. THE NORTHERN
INNER CHANNELS ARE EXPECTED TO BEGIN TO INCREASE AGAIN TO 15 TO 25
KTS OVERNIGHT INTO MONDAY MORNING AS THE FRONT APPROACHES, WITH
LYNN CANAL REACHING CLOSER TO 30 TO 35 KTS BY MONDAY AFTERNOON.
THE STRONG SOUTHERLY WINDS WILL SPREAD THROUGH THE REST OF THE
CENTRAL INNER CHANNELS THROUGH MONDAY AND INTO THE SOUTHERN INNER
CHANNELS BY TUESDAY MORNING. ANTICIPATING PERIODS OF GALE FORCE
WINDS TO SPREAD THROUGHOUT THE INNER CHANNELS THROUGH TUESDAY,
BRINGING 6 TO 8 FT WAVE HEIGHTS THROUGH MUCH OF THE PANHANDLE.
WINDS IN THE SOUTHERN AND CENTRAL PANHANDLE SHOULD BEGIN TO
DECREASE TUESDAY NIGHT, WHILE PARTS OF THE NORTHERN PANHANDLE LOOK
TO STAY ELEVATED THROUGH WEDNESDAY.
HYDROLOGY
A STRONG SYSTEM IS EXPECTED TO MOVE INTO THE
NORTHERN CENTRAL GULF, REINFORCING THE EXISTING LOW PRESSURE
SYSTEM, AND DRAWING A DEEPER FETCH OF MOISTURE FROM NORTHERN
PACIFIC. BY TUESDAY MORNING, THIS PLUME OF MOISTURE IS EXPECTED TO
SHIFT FROM SOUTHWEST TO SOUTHERLY, AND IS LIKELY TO EXCEED 600
KG/MS IVT FOR AROUND A 12-18 HOUR PERIOD FOR ANY GIVEN LOCATION IN
THE ICY STRAIT CORRIDOR AND NE GULF COAST. EXPECTING YAKUTAT TO
BE THE BIG WINNER IN TERMS OF RAIN AMOUNTS, WITH NEAR PERFECT
PERPENDICULAR FLOW, STRONG WAA IN THE LOW LEVELS INCREASING LIFT
POTENTIAL, AND DECENT DIVERGENCE ALOFT. WITH THIS, YAKUTAT COULD
SEE UPWARDS OF 6 INCHES DURING A 36 HOUR PERIOD, WHICH IS A LITTLE
HIGHER THAN A 2 YEAR ARI EVENT. THERE ARE LOWER PROBABILITIES OF
AROUND 30% TO SEE A 5 YEAR EVENT FOR 36 HOURS FOR THE NE GULF
COAST, AND EVEN HIGHER ARIS ARE POSSIBLE FURTHER INTO YAKUTAT BAY.
THESE HIGHER ARIS LOOK TO EXTEND DOWN THE COAST AND INTO THE
GLACIER BAY AREA, WITH MAY AREAS ALONG SOUTH FACING SLOPES
EXCEEDING 5 YEAR RETURN INTERVALS AND APPROACHING ON 10 YEAR OVER
A 36 HOUR PERIOD. THEREFORE, ADDED ELFIN COVE, SPECIFICALLY FOR
THE MOUNTAINS TO THE NORTH, THE NE GULF COAST, AND GLACIER BAY TO
THE FLOOD WATCH. THIS IS MAINLY FOR AREAL FLOODING OF LOW LYING
AREAS AND PONDING OF WATER. THAT BEING SAID, THE WIND COMPONENT OF
THIS SYSTEM HAS WIND GUSTS GREATER THAN 40 MPH AT ELEVATIONS
GREATER THAN 500 FT, AND GREATER THAN 60 MPH AT ELEVATIONS AROUND
2000 FT. CURRENT THINKING IS THE HIGH RAIN RATES COMBINED WITH
HIGHER RETURN INTERVALS IN THE UPPER RAINFALL RANGES (HIGHER
PERCENTILES, LOWER PROBABILITY) LEADS TO AN INCREASED RISK OF
ISOLATED LANDSLIDES IN STEEP TERRAIN BASED ON HISTORICAL
ATMOSPHERIC CONDITIONS.
AJK WATCHES/WARNINGS/ADVISORIES
PUBLIC...WIND ADVISORY FROM 4 PM MONDAY TO 10 PM AKDT TUESDAY FOR AKZ317.
FLOOD WATCH FROM MONDAY EVENING THROUGH LATE TUESDAY NIGHT FOR
AKZ317-320-322-325.
HIGH WIND WATCH FROM MONDAY EVENING THROUGH WEDNESDAY AFTERNOON
FOR AKZ318.
WIND ADVISORY FROM 4 PM MONDAY TO 4 AM AKDT WEDNESDAY FOR AKZ319.
WIND ADVISORY FROM 9 PM MONDAY TO 4 AM AKDT WEDNESDAY FOR
AKZ320>322-325.
WIND ADVISORY FROM 1 AM TUESDAY TO 4 AM AKDT WEDNESDAY FOR
AKZ323-324-327.
WIND ADVISORY FROM 10 AM TUESDAY TO 4 AM AKDT WEDNESDAY FOR
AKZ330-332.
MARINE...GALE WARNING FOR PKZ011>013-021-022-031>036-053-641>644-651-652-
661>664-671-672.
UPDATE...DS
SHORT TERM...NC
LONG TERM...DS
AVIATION...BAS
MARINE...ZTK
HYDROLOGY...NC
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