501
FXAK67 PAJK 180128 AAC
AFDAJK
SOUTHEAST ALASKA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JUNEAU AK
528 PM AKDT SAT OCT 17 2026
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 THURSDAY/
AN ACTIVE FALL-TIME WEATHER PATTERN WILL CONTINUE ACROSS SEAK
NEXT WEEK. MONDAY WILL START OFF WITH A RIDGE OF HIGH PRESSURE
OVER MOST OF THE PANHANDLE, WHICH COULD LEAD TO FOG DEVELOPMENT,
WITH WEAKER ONSHORE FLOW AND LIGHT SHOWERS AHEAD OF THE NEXT
SYSTEM. A PROGRESSIVE LOW AND COLD FRONT WILL TREK ACROSS THE GULF
AND REACH YAKUTAT MONDAY AFTERNOON BEFORE SWEEPING SOUTHEAST
ACROSS THE PANHANDLE MONDAY NIGHT INTO EARLY TUESDAY BEFORE
WEAKENING AND STALLING ACROSS SOUTHERN PANHANDLE, WITH ONSHORE
FLOW BEHIND BRINGING STEADY RAIN INTO THE PANHANDLE. TOTAL
PRECIPITATION WITH THIS INITIAL SYSTEM WILL REMAIN RELATIVELY
LIMITED, THOUGH A BRIEF PERIOD OF MODERATE TO HEAVY RAIN AND
INCREASING SOUTHERLY WINDS WILL DEVELOP AHEAD OF THE FRONTAL
BOUNDARY. BEHIND THIS INITIAL SYSTEM, A STRONGER LOW IS FORECAST
TO DEEPEN RAPIDLY (~960 MB) AS IT LIFTS NORTHEAST INTO THE
NORTHERN GULF OF ALASKA ON TUESDAY, STALLING THROUGH MIDWEEK
BEFORE GRADUALLY WEAKENING AND DISSIPATING ON THURSDAY. THIS
STRONG LOW WILL QUICKLY SEND ANOTHER FRONT AND DEEPER MOISTURE
FEED TOWARD AND THROUGH SEAK TUESDAY INTO WEDNESDAY, BRINGING
MODERATE TO HEAVY RAIN AND STRONG GUSTY WINDS, ALONG WITH SEVERE
MARINE HAZARDS. SOUTH TO SOUTHEASTERLY WINDS WILL INTENSIFY
SIGNIFICANTLY ON TUESDAY, PRODUCING GALE- FORCE CONDITIONS IN
INNER CHANNELS SUCH AS NORTHERN LYNN CANAL AND CLARENCE STRAIT,
WITH GALES (34-47 KT) AND POSSIBLY STORM-FORCE WINDS (48–55 KTS)
AND COMBINED SEAS EXCEEDING 20 FEET ALONG OUTER COASTAL WATERS,
MAINLY FROM CAPE SPENCER NORTHWARD. BY THURSDAY, CONDITIONS WILL
IMPROVE BEHIND THE FRONTAL PASSAGE AND AS THE LOW IN THE NORTHERN
GULF WEAKENS, THOUGH LINGERING ONSHORE FLOW WILL SUSTAIN RAIN
SHOWERS, WHILE WINDS AND SEAS SLOWLY SUBSIDE.
PERSISTENT ONSHORE FLOW WITH MAINLY CLOUDY SKIES AND RAIN WILL
KEEP TEMPERATURES COOL AND CONSISTENT THROUGH THE PERIOD, WITH
DAYTIME HIGHS IN THE MID TO UPPER 40S (LOW 50S POSSIBLE ON
TUESDAY) AND OVERNIGHT LOWS IN THE UPPER 30S TO LOW 40S.
AVIATION
WE WILL CONTINUE TO MVFR PREVAILING IN PATCHY LIGHT
RAINS ACROSS THE ALASKA PANHANDLE THROUGH TONIGHT, WITH LOCALIZED
IFR IN SCATTERED TO NUMEROUS PERIODIC SHOWERS MOVING ACROSS ON
THE EAST AND SOUTHEAST SIDE OF A LOW PRESSURE AREA MOVING SOUTH OF
YAKUTAT. THIS PATTERN WILL CONTINUE INTO SUNDAY AS A WEAK REMNANT TROUGH
PERSISTS ACROSS THE PANHANDLE. WE DO SEE SOME BREEZY BOUNDARY
LAYER WINDS (FOR THE LOWEST 5 THOUSAND FEET OR SO) WITH GUSTS TO
AROUND 30 KTS THROUGH THIS EVENING, THEN WINDS DIMINISH LATE
TONIGHT AND TOWARD MORNING. 05/GARMON
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...GARMON
MARINE...JONES
HYDROLOGY...COMPTON
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