333
FXAK67 PAJK 180455
AFDAJK
SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
855 PM AKDT SAT OCT 17 2026
UPDATE
UPDATE FOR THE LONG TERM DISCUSSION AND THE 06Z TAF
ISSUANCE.
SYNOPSIS
KEY MESSAGES:
- NUMEROUS LIGHT TO MODERATE SHOWERS MOVING THROUGH TONIGHT AS A
WEAK LOW PRESSURE SYSTEM MOVES INLAND ACROSS THE FAIRWEATHER
RANGE.
- A BRIEF BREAK IN THE PERSISTENT RAIN IS POSSIBLE SUNDAY NIGHT
INTO MONDAY, HOWEVER ANOTHER FRONT AND ROUND OF HEAVIER RAIN AND
WIND PUSH ACROSS THE GULF OF ALASKA INTO THE ALASKA PANHANDLE BY
TUESDAY.
- MARITIME INTERESTS NEED TO PAY ATTENTION TO A STRONG FRONT
PROJECTED TO MOVE ACROSS THE GULF OF ALASKA BY TUESDAY, BRINGING
GALE FORCE TO POTENTIALLY STORM FORCE WINDS TO THE CENTRAL AND
EASTERN GULF TUESDAY INTO WEDNESDAY.
SHORT TERM
ONGOING CONVECTIVE SHOWERS FOR MOST OF THE
PANHANDLE DESCRIBES THE NEXT 24 HOURS WELL. A DEEPER BUT FILLING
UPPER LEVEL LOW IN THE NORTHERN GULF CONTINUES TO BRING ONSHORE
FLOW FROM THE SOUTHWEST FOR THE PANHANDLE, BRINGING PREDOMINANTLY
RAIN SHOWERS FOR WEST FACING MOUNTAINS. ONE CHANGE TO THE EVENING
TIMEFRAME FORECAST IS THE REMOVAL OF THUNDERSTORMS FROM THE NE
GULF COAST. BASED ON NUCAPS SOUNDINGS, A BULK OF THE EXPECTED
200-300 CAPE WAS LOCATED AROUND THE 0 TO -5 CELSIUS RANGE, WHICH
IS NOT EXPECTED TO BE DEEP ENOUGH TO YIELD ANY SUBSTANTIAL
LIGHTNING STRIKES. AT THIS POINT, THE CHANCE FOR LIGHTNING IS LESS
THAN 5% IN ANY GIVEN AREA.
THE LOW PRESSURE SUCCESSFULLY FILLS BY SUNDAY NIGHT, REPLACED BY
BUILDING HIGH PRESSURE, PARTICULARLY IN THE SOUTHERN PANHANDLE.
WITH CURRENT AND UPCOMING RAINFALL FOR THE SOUTHERN PANHANDLE,
EXPECTING TO SEE DEWPOINTS STAY RELATIVELY HIGH OVERNIGHT. WITH
CLEARING SKIES AND LIGHTER WINDS, COULD SEE SOME AREAS OF FOG FOR
THE MARINE WATERS AND LAND AREA FOR POW, REV ISLAND, AND UP TO
SUMNER STRAIT AREA. THIS AREA OF FOG MAY BE EXPANDED AS WE GET
CLOSER IN TIME.
MONDAY SEES THE PRELUDE TO THE STRONGER SYSTEM MOVING IN TUESDAY.
A WARM OCCLUDED FRONT IS SCHEDULED TO MOVE NORTHEAST OVER THE NE
GULF COAST AND NORTHERN HALF OF THE PANHANDLE LATE MONDAY MORNING
AND INTO MONDAY NIGHT. LIGHT TO MODERATE RAIN AHEAD OF THE FRONT
WITH A SLIGHT INCREASE IN WINDS. THE SECONDARY ROUND OF ENERGY
RACING UP INTO KODIAK ISLAND WILL REINFORCE THIS LOW PRESSURE NEAR
PRINCE WILLIAM SOUND, DEEPENING TO 970 OR LOWER BY TUESDAY
MORNING. THE ASSOCIATED WARM FRONT WILL BRING MODERATE TO HEAVY
RAIN FOR THE ICY STRAIT CORRIDOR, NORTHERN INNER CHANNELS, AND NE
GULF COAST, ALONG WITH VERY GUSTY WINDS. FOR MORE INFORMATION, SEE
THE HYDROLOGY AND LONG TERM SECTION.
LONG TERM.../TUESDAY THROUGH FRIDAY/
TUESDAY WILL BEGIN WITH MODERATE TO HEAVY RAINFALL AND GUSTY
SOUTHERLY WINDS ACROSS NORTHERN PANHANDLE WITH AN OCCLUDED FRONT
PUSHING ASHORE WITH A DEEPER FEED OF MOISTURE. THROUGHOUT THE
DAY, A RAPIDLY DEEPENING SURFACE LOW WILL LIFT NORTHEAST INTO THE
NORTHERN GULF, WITH A QUICK MOVING COLD FRONT TRAVERSING THE GULF
AND THROUGH THE PANHANDLE, CLEARING THE SOUTHERN PANHANDLE ON
WEDNESDAY MORNING. ALONG AND AHEAD OF THE FRONT, AN ATMOSPHERIC
RIVER WILL TAP INTO A DEEPER FEED OF SUBTROPICAL MOISTURE, WITH
HEAVY RAINFALL AND STRONG WINDS FEEDING INTO THE PANHANDLE, WITH
HIGHEST RAIN AMOUNTS AND STRONGEST WINDS ACROSS THE NORTHEAST GULF
COAST AND NORTHERN PANHANDLE. SOUTH TO SOUTHEASTERLY WINDS WILL
INTENSIFY, PRODUCING GALE-FORCE CONDITIONS IN INNER CHANNELS SUCH
AS NORTHERN LYNN CANAL AND CLARENCE STRAIT, WITH WIDESPREAD GALES
(34-47 KT) TO STORM-FORCE WINDS (48–63 KTS) AND COMBINED SEAS
EXCEEDING 20 FEET ALONG OUTER COASTAL WATERS, MAINLY FROM CAPE
EDGECOMBE NORTHWARD.
AS THE PRIMARY LOW STALLS AND WEAKENS IN THE NORTHERN GULF
THROUGH THE END OF THE WEEK, ONSHORE FLOW AND SUBTLE TROUGHS
SWINGING AROUND THE LOW WILL KEEP HIGHER PRECIPITATION CHANCES
WITH MODERATE TO HEAVY SHOWERS AND GUSTY WINDS ACROSS SEAK
THROUGH THURSDAY. QUITE A BIT OF MODEL DISCREPANCY BY THE END OF
THE WEEK, BUT GENERAL TREND IS FOR THE LOW TO WEAKEN FURTHER AS IT
SHIFTS SOUTHEAST, WITH A RIDGE OF HIGH PRESSURE BUILDING IN ITS
WAKE, BRINGING CLEARING SKIES AND DRIER OFFSHORE FLOW.
PERSISTENT ONSHORE FLOW WITH MAINLY CLOUDY SKIES AND RAIN WILL
KEEP TEMPERATURES COOL AND CONSISTENT THROUGH THE PERIOD, WITH
DAYTIME HIGHS IN THE 40S (LOW 50S POSSIBLE ON TUESDAY) AND
OVERNIGHT LOWS IN THE MID 30S TO LOW 40S.
SNOW LEVELS MAY INITIALLY BE LOW ENOUGH FOR SNOW OR RAIN/SNOW MIX
NEAR WHITE PASS EARLY TUESDAY MORNING, BUT WILL QUICKLY RISE
THROUGHOUT THE DAY AS SOUTHERLY WINDS PICK UP AHEAD OF THE FRONT.
SNOW LEVELS WILL FALL DOWN TO 1-2KFT BEHIND THE FRONT TUESDAY
NIGHT/WEDNESDAY AND SNOW SHOWERS WILL BE POSSIBLE ALONG THE
KLONDIKE HIGHWAY AND THE UPPER REACHES OF THE HAINES HIGHWAY
THROUGH THURSDAY, ALTHOUGH ANY ACCUMULATIONS LOOK TO BE LIGHT FOR
NOW.
AVIATION.../THROUGH SUNDAY EVENING/
A LOW PRESSURE CENTER,
LOCATED JUST OFF THE COAST NEAR YAKUTAT HAS BROUGHT MODERATE TO
HEAVY RAIN SHOWERS ACROSS THE REGION ALONGSIDE BREEZY WINDS IN THE
LOWER LEVELS WITH GUSTS REACHING AROUND 30 KTS, BEFORE
DIMINISHING LATE TONIGHT AND TOWARD MORNING. AS THE LOW WEAKENS,
WINDS ALOFT BEGIN TO DWINDLE AND THE THREAT OF LLWS SUBSIDES INTO
THE EVENING HOURS, THOUGH STRONGER WINDS GUSTS COULD GENERATE
TURBULENCE BELOW MOUNTAIN TOP LEVELS.
MVFR CONDITIONS WILL CONTINUE TO PREVAIL WITH LIGHTER RAIN SHOWERS
TRIGGERING OVER HIGHER TERRAIN THROUGH TONIGHT, ACCOMPANIED BY
LOCALIZED IFR CONDITIONS DURING THE PASSING OF SCATTERED PERIODIC
SHOWERS. IN BETWEEN THESE SHOWERS, CONDITIONS IMPROVE TO HIGH-END
MVFR OR LOW-END VFR WITH CIGS GENERALLY SETTLING BETWEEN 2500 AND
3500 FT. WHILE EXTENSIVE CLEARING IS NOT EXPECTED OVERNIGHT, BRIEF
BREAKS IN CLOUD COVER AS WINDS CALM MAY ALLOW FOR SHALLOW/PATCHY FOG
FORMATION NEAR WRANGELL AND PETERSBURG, CAUSING DROPS IN VSBY. THIS
SHOWERY PATTERN WILL CONTINUE INTO SUNDAY AS A WEAK TROUGH PERSISTS
ACROSS THE PANHANDLE, WHICH WILL EVENTUALLY GIVE WAY TO HIGH
PRESSURE, PROVIDING ADDITIONAL CLEARING BY SUNDAY NIGHT AND AN
OVERALL IMPROVING TREND.
MARINE
OUTSIDE WATERS: A WEAKENING LOW IN THE NORTHERN GULF WILL CONTINUE
TO MOVE INLAND ALONG THE NORTHEAST GULF COAST SATURDAY NIGHT. THIS
WILL ACCELERATE DROPPING OF WINDS AND SEAS IN THE GULF SUNDAY AS
A WEAK RIDGE OF HIGH PRESSURE BRIEFLY BUILDS INTO THE GULF FOR THE
TAIL END OF THE WEEKEND. SEAS LOOK TO DROP FROM 8 TO 13 FT ACROSS
THE GULF SATURDAY NIGHT, TO 7 FT OR LESS BY LATE SUNDAY
AFTERNOON. THE NEXT WEATHER OF NOTE WILL BE A SYSTEM POTENTIALLY
UP TO STORM FORCE SET TO MOVE INTO THE WESTERN GULF EARLY NEXT
WEEK, WITH WINDS AND SEAS BUILDING THROUGH MONDAY.
INSIDE WATERS: WITH THE LOW IN THE NORTHERN GULF AND ASSOCIATED
FRONT CONTINUING TO LIFT NORTHWARD TO THE INTERIOR, WINDS ALONG
THE INNER CHANNELS NORTH OF FREDERICK SOUND HAVE PICKED UP AND
WILL REMAIN ELEVATED THROUGH THE EVENING HOURS SATURDAY BEFORE
GRADUALLY DIMINISHING LATE AND THROUGH THE DAY SUNDAY. ONLY LYNN
CANAL IS EXPECTED TO MAINTAIN BREEZY CONDITIONS A BIT LONGER
THROUGH FIRST HALF OF SUNDAY AS A BRIEF RIDGE ROTATES THROUGH THE
CENTRAL GULF. WITH DIMINISHING WINDS TO END THE WEEKEND, SOME FOG
POTENTIAL SUNDAY NIGHT PARTICULARLY FOR THE SOUTHERN INNER
CHANNELS. OTHERWISE INCREASING WINDS EARLY WEEK WITH A STRONG
SYSTEM MOVING INTO THE GULF AND THROWING A FRONT TOWARDS THE
PANHANDLE.
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 500 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. FOR THE JUNEAU AND GUSTAVUS AREAS SPECIFICALLY,
RAINFALL AMOUNTS LOOK VERY SIMILAR TO THE PREVIOUS ATMOSPHERIC
RIVER FROM LAST WEEK WHICH PUT SALMON RIVER AND MONTANA CREEK INTO
MINOR FLOOD STAGE. THEREFORE, ISSUED A HYDROLOGIC OUTLOOK FOR
THESE AREAS FOR EXPECTED MINOR FLOODING AT LEAST.
THERE IS A LARGE WIND COMPONENT TO THIS SYSTEM AS WELL, WITH
GUIDANCE CONTINUING TO INDICATE UNSEASONABLY STRONG WIND
ASSOCIATED WITH THIS SYSTEM. THAT BEING SAID, RAIN TOTALS AND
RAIN RATES LOOK TOO WEAK TO MEET HISTORICAL ATMOSPHERIC AND SOIL
CONDITIONS AT WHICH ISOLATED LANDSLIDES HAVE BEEN OBSERVED.
AJK WATCHES/WARNINGS/ADVISORIES
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012-013-022-031-053-641>644-651-652-
661>664-671-672.
SHORT TERM...COMPTON
LONG TERM...SLAGLE
AVIATION...SULLIVAN
MARINE...JONES
HYDROLOGY...COMPTON
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