557
FXAK67 PAJK 092321
AFDAJK
SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
321 PM AKDT WED SEP 9 2026
SYNOPSIS
KEY MESSAGES:
- SHOWER POTENTIAL SHIFTS SOUTHEASTWARD AND DIMINISHES THROUGH
WEDNESDAY AFTERNOON, WITH SKIES CLEARING BEHIND. NORTHERLY WINDS
BUILD ACROSS THE INNER CHANNELS THURSDAY.
- HIGH PRESSURE RETURNS THROUGH THE END OF THE WEEK WITH DRIER
CONDITIONS, MORE SUNSHINE, AND HIGH TEMPERATURES IN THE MID 60S
TO LOW 70S.
SHORT TERM
NOT MUCH TO ALTER THIS AFTERNOON WITH THE FORECAST. GUIDANCE HAS HAD
A PRETTY GOOD HANDLE ON THIS SYSTEM FOR SEVERAL DAYS, AND IT HAS
PLAYED OUT MUCH ALONG THOSE LINES. SATELLITE SHOWS A WELL DEFINED
FRONT TRANSITING THE PANHANDLE FROM NORTH TO SOUTH, WITH CLEARING
BEHIND IT. THAT CLEARING WILL SET UP THE CENTRAL PANHANDLE WELL FOR
RADIATIVE COOLING TONIGHT, AND LIKELY FOG IN THE MORNING FOR THE
INNER CHANNELS THERE. AS FOR THE NORTH AND SOUTH, SEEMS THE MARINE
LAYER WILL HANG A BIT TOO LONG IN THE SOUTH TO ALLOW SUFFICIENT
COOLING FOR FOG FORMATION, AND UP TOP WINDS WILL HAVE BEGUN TO PICK
UP, PREVENTING EFFICIENT COOLING AND STABILIZATION.
AS THE FRONT MAKES ITS WAY SOUTH, RAIN WILL COME TO AN END. WITH HOW
OVERCAST THE SOUTHERN PANHANDLE IS, A THUNDERSTORM OFFSHORE IS LESS
LIKELY. HOWEVER, THE PROOF IS IN THE PUDDING, SO TO SPEAK, AS THERE
IS EVIDENCE FOR A REGION OF INSTABILITY ACCOMPANYING THE VORT MAX OF
THE SYSTEM, AS A FEW LIGHTNING STRIKES WERE DETECTED OFF THE COAST
OF KRUZOF ISLAND EARLIER THIS AFTERNOON, SO A SLIGHT CHANCE OF
THUNDER WILL BE MAINTAINED OFFSHORE IN THE SOUTH THROUGH THIS
EVENING.
A RETURN TO SUMMERY CONDITIONS WILL BE UNDERWAY AFTER THIS FRONT IS
FINISHED REMINDING US WHAT RAIN LOOKS LIKE. CLEARER SKIES AND
SUNNIER, WARMER CONDITIONS WILL PREVAIL AS A RIDGE BECOMES SITUATED
OVER THE GULF.
LONG TERM.../FRIDAY THROUGH MONDAY/
NO MAJOR CHANGES TO BE
SEEN IN THE EXTENDED FORECAST WITH A RIDGE OF HIGH PRESSURE
BUILDING IN OVER THE GULF COME FRIDAY. THIS WILL FINALLY DISLODGE
THE WEAK TROUGHING OVER THE PANHANDLE AND USHER IN MORE CONSISTENT
DRY CONDITIONS THIS WEEKEND AND OVERALL BENIGN WEATHER. AS
MENTIONED IN PREVIOUS DISCUSSIONS, A TIGHTENING GRADIENT EARLY
FRIDAY FAVORING NORTH SOUTH ORIENTED CHANNELS IS EXPECTED TO BRING
ABOUT SOME STOUT NORTHERLY WINDS. HOWEVER THESE SHOULD QUICKLY
DIMINISH THROUGH THE AFTERNOON HOURS FRIDAY WITH WINDS ACROSS THE
INNER CHANNELS AND COASTAL WATERS LARGELY FALLING TO 10 KT OR
LESS. WITH THE DRIER CONDITIONS, LOCALIZED SEA BREEZES ARE
EXPECTED THROUGH THE WEEKEND BUT SHOULD NOT BE PARTICULARLY
IMPACTFUL.
THE MAIN QUESTION IN THE LONG TERM REMAINS WHETHER A LOW DEVELOPS
IN THE NORTHERN GULF TO TAKE A SWIPE AT THE NORTHERN PANHANDLE
EARLY NEXT WEEK. MODELS ARE STILL NOT SOLD ON THE IDEA, THOUGH
THERE IS A SLIGHT TREND FOR A MAJORITY OF THE ASSOCIATED
PRECIPITATION TO REMAIN OVER THE INTERIOR. OVERALL THOUGH THE MAIN
TAKEAWAY IS STILL FOR ANOTHER ROUND OF MORE SUMMER-LIKE WEATHER
THIS WEEKEND WITH FAIRLY DRY CONDITIONS AND DAYTIME HIGHS TO
REBOUND TO THE MID 60S TO AROUND 70 FOR MOST OF THE PANHANDLE.
AVIATION.../THROUGH 00Z FRIDAY/
A LOW PRESSURE SYSTEM MOVING
SE ALONG THE GULF COAST HAS BROUGHT SOME SHOWERS ACROSS THE ALASKA
PANHANDLE. HEAVIER SHOWERS HAVE BROUGHT BRIEF PERIODS OF MVFR
CEILINGS, AND IFR VISIBILITIES. THIS ACTIVITY HAS MOSTLY IMPACTED
THE NORTHERN PANHANDLE, AND MAY IMPACT PETERSBURG AND WRANGELL
THROUGH 05Z THURSDAY. AS A RIDGE BUILDS IN BEHIND THE TROUGH, FOG
IS POSSIBLE ACROSS THE ALASKA PANHANDLE TONIGHT. FOG POTENTIAL
APPEARS HIGHEST FOR PETERSBURG AND WRANGELL.
WITH THE RIDGE DEVELOPING TONIGHT, AND THE LOW CONTINUING
SOUTHEASTWARD, THIS WILL LEAD TO AN INCREASING PRESSURE GRADIENT FOR
THE NORTHERN PANHANDLE. THE STRONGEST WINDS ARE EXPECTED FOR LYNN
CANAL, WHERE NORTHERLY GUSTS UP TO 30 KTS ARE POSSIBLE. AFTER 20Z
THURSDAY, CONDITIONS ARE EXPECTED TO BE GENERALLY VFR. FOR JUNEAU
AND GUSTAVUS, SEA BREEZES ARE EXPECTED TO DEVELOP THURSDAY AFTER
18Z.
MARINE
OUTER WATERS: GENERALLY DOWNWARD TREND THROUGH THE TONIGHT PERIOD,
AS THE FRONT EXISTS INTO SOUTHERN BRITISH COLUMBIA. WAVE HEIGHTS,
DRIVEN BY PROLONGED STRONG WINDS AND A MODEST WESTERLY SWELL LOOK
TO DIMINISH FROM 8-12 FT AT 9 SECONDS TO 4-5 FT BY FRIDAY NIGHT AT
AROUND 15 SECONDS WITH VERY LITTLE SWELL INFLUENCE. EXPECTING TO
SEE HIGHEST WAVE HEIGHTS AND WIND SPEEDS OUT OF CHATHAM STRAIT AND
INTO DIXON ENTRANCE FROM UNSEASONABLY STRONG NORTHERLIES, BEFORE
FALLING OFF FRIDAY MORNING.
INSIDE WATERS: MAIN STORY THROUGH FRIDAY IS A TRANSITION FROM
SOUTHERLY WINDS TO NORTHERLY TONIGHT, STRENGTHENING THROUGH THE
DAY THURSDAY, AND PEAKING OVERNIGHT THURSDAY NIGHT INTO FRIDAY.
HIGH PRESSURE FROM A COLD FRONT IN CANADA, IN COMBINATION WITH A
SHORTWAVE TROUGH MOVING DOWN FROM THE YUKON, LOOK TO INCREASE
NORTHERLIES IN NORTH SOUTH FACING CHANNELS LIKE LYNN CANAL,
CHATHAM STRAIT, AND STEPHENS PASSAGE. EXPANDED OUT THE AREAS OF
STRONG BREEZES TO EXIT CHATHAM STRAIT INTO THE GULF, BUT NOTABLY
DID NOT INCREASE LYNN CANAL UP TO GALE FORCE. PRESSURE GRADIENTS
FOR THIS AREA LOOK TO APPROACH AROUND A 7 MB DIFFERENCE BETWEEN
WHITEHORSE AND JUNEAU, WHICH HAS HISTORICALLY ONLY CAUSED GALE
FORCE WINDS 20% OF THE TIME. THEREFORE, KEPT GALES OUT OF THE
FORECAST, AS THE MORE LIKELY SCENARIO WILL BE LYNN CANAL
MAXIMIZING AROUND 30 KNOTS
AJK WATCHES/WARNINGS/ADVISORIES
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012-013-022-032-033-641>644-651-
661>664-671-672.
SHORT TERM...VFJ
LONG TERM...STJ
AVIATION...MUSALL
MARINE...NC
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