619
FXAK67 PAJK 031823 AAA
AFDAJK
SOUTHEAST ALASKA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JUNEAU AK
1023 AM AKDT WED SEP 3 2025
UPDATE
AVIATION DISCUSSION FOR 18Z TAF ISSUANCE.
ALSO UPDATE TO CANCEL THE HEAT ADVISORY FOR THE SOUTHERN
PANHANDLE. LOW CLOUDS INTO CLARENCE STRAIT AND TO THE SOUTHERN
INNER CHANNELS AND EASTERN PRINCE OF WALES ISLAND, AS A RESULT THE
TEMPERATURES WILL BE REDUCED AND SHOULD STAY BELOW 70 DEGREES.
SHORT TERM
NO MAJOR CHANGES TO ONGOING FORECAST, SAVE FOR THE
ADDITION OF ADDING LOCALIZED OCEAN EFFECT WINDS TO SOME MARITIME
AREAS THROUGH THE DAY ON WEDNESDAY. OVERLAND AND INNER CHANNEL
WINDS REMAIN LARGELY 10KTS OR LESS, ALTHOUGH OCEAN EFFECT WINDS
WILL REACH UP TO 15 TO 20 KT FOR SOME LOCATIONS THROUGH THE
DAYTIME HOURS. CONTINUED RIDGING ALOFT HAS ENABLED A RESURGENT
MARINE LAYER TO PUSH INTO THE SOUTHERN PANHANDLE, AS WELL AS PARTS
OF THE OUTER COAST LIKE YAKUTAT. ALTHOUGH THE MARINE LAYER WILL
FALL BACK DURING THE DAYTIME HOURS, EXPECT IT TO RETURN WEDNESDAY
NIGHT INTO THURSDAY, REACHING UP FROM THE SOUTH INTO THE CENTRAL
PANHANDLE AND THE CENTRAL INNER CHANNELS.
LONG TERM
KEY MESSAGES:
- HIGH PRESSURE OVER THE GULF CONTINUES WARM, DRY WEATHER
- TEMPERATURES REMAIN ABOVE NORMAL THROUGH MIDWEEK
- SLIGHT COOLING OVER THE WEEKEND WITH INCREASING CLOUDS AND RAIN
CHANCES, PARTICULARLY FOR NORTHERN GULF COAST
A BLOCKING RIDGE AND ACCOMPANYING SURFACE HIGH PRESSURE IN THE
CENTRAL GULF WILL WEAKEN SLIGHTLY LATER THIS WEEK, BUT STILL
DOMINATE THE OVERALL PATTERN FOR SOUTHEAST ALASKA. WARM AND DRY
SUMMER WEATHER WILL CONTINUE, WITH THE SOUTHERN PANHANDLE STILL ON
THE RECEIVING END OF THE WARMEST TEMPERATURES, REACHING THE UPPER
70S WITH ISOLATED AREAS FURTHER INLAND REACHING 80 THURSDAY. LACK
OF CLOUD COVER COMBINED WITH DAYTIME HEATING WILL CONTINUE TO LEAD
TO BRISK SEA BREEZES FOR COMMUNITIES ALONG THE INNER CHANNELS,
WITH THE STRONGEST WINDS EXPECTED IN NORTHERN LYNN CANAL AND TAIYA
INLET WITH THERMAL TROUGHING DEVELOPING OVER THE INTERIOR. EXPECT
THESE TO PICK UP IN THE AFTERNOON HOURS TO MODERATE TO FRESH
BREEZE CONSISTENTLY THROUGH MIDWEEK BUT TO A LESSER EXTENT
HEADING INTO THE WEEKEND. THIS IS DUE TO THE SURFACE HIGH PRESSURE
WEAKENING SLIGHTLY IN THE GULF DUE TO A LOW MOVING INTO THE
ALASKA PENINSULA. THIS WILL LEAD TO A FURTHER SLACKENING OF THE
GRADIENT OVER THE CENTRAL AND EASTERN GULF AND THUS FURTHER
DIMINISHING OF WINDS IN THAT AREA, AS WELL AS SEAS OF 5 FT OR
LESS, MAINLY DRIVEN BY A WESTERLY SWELL PUSHING INTO THE CENTRAL
AND EASTERN GULF ON FRIDAY.
IN TERMS OF RAINFALL, THERE IS NOT MUCH TO BE HAD DUE TO THE
BLOCKING RIDGE DEFLECTING ALMOST ANY DEVELOPING SYSTEMS AWAY FROM
OUR SIDE OF THE GULF. AN UPPER LEVEL TROUGH NEAR IN THE LATTER
HALF OF THE WEEK WILL BRING LIGHT RAIN CHANCES (UP TO 30 %) TO
THE NORTHERN GULF COAST ALONG WITH LIGHT SHOWER CHANCES TO THE
OUTER COAST, BUT THE NEXT ORGANIZED SYSTEM THAT HAS A CHANCE TO
PROPERLY BREAK US OUT OF THE DRY AND WARM PATTERN CONTINUES TO BE
ELUSIVE. FOR THE RAIN CHANCES THIS WEEKEND, MODEL ENSEMBLES ARE
TRENDING TOWARDS TRYING TO BREAK DOWN THIS RIDGE AND PUSH A MORE
PERSISTENT TROUGH AND SURFACE LOW INTO THE GULF EARLY NEXT WEEK,
BUT TIME WILL TELL.
AVIATION
FOR WEDNESDAY MORNING, THE FORECASTED MARINE LAYER
HAS FILLED THE VAST MAJORITY OF CLARENCE STRAIT AND ADJACENT
FJORDS AS IT PUSHED NORTHWARD FROM DIXON ENTRANCE, WITH PAKT, PAHY
AND PAMM STILL REPORTING CIGS AOB 500 FT AS OF 18Z. STILL EXPECT
THIS LAYER TO SLOWLY BURN OFF NEAR 20Z WEDNESDAY FROM NORTH TO
SOUTH, WITH VFR PREVAILING INTO THE LATE AFTERNOON. THESE IFR
CIGS FROM THIS STOUT MARINE LAYER WILL RETURN WEDNESDAY NIGHT IN
SIMILAR AREAS ALONG THE SOUTHERN PANHANDLE. THERE IS SOME
INDICATION THAT THIS LAYER WILL SPREAD EVEN FURTHER NORTH
THURSDAY, IMPACTING MORE OF THE CENTRAL PANHANDLE AS FAR NORTH AS
SUMNER STRAIT, AS WELL AS SITKA ALONG THE OUTER COAST.
STRONGEST WINDS THROUGH WEDNESDAY UP TO AND AROUND 15KTS AND
GUSTS UP TO POSSIBLE 25KTS UNDER ANY SEA BREEZE INTERACTIONS IN
THE AFTERNOON IN SOME LOCATIONS. NO LLWS CONCERNS THROUGH THE TAF
PERIOD.
MARINE
OUTSIDE: LITTLE CHANGE FROM YESTERDAY. HIGH PRESSURE
CONTINUES TO CONTROL OUR SKIES HERE IN SE AK. SWELL REMAINS OUT OF
THE SOUTH AT 2FT 14-18 SECONDS, WITH WIND WAVES OF 6 TO 10 FT LESS
THAN 10 SECONDS ALONG THE PRINCE OF WALES (POW) COAST AND DIXON
ENTRANCE. THESE WIND WAVES ARE BEING DRIVEN BY FRESH TO STRONG
BREEZES (17 TO 27 KNOTS) OUT OF THE NW, HIGHEST WINDS OFF THE COAST
OF POW AND CAPE FAIRWEATHER. WIND SPEEDS LOOK TO DECREASE FOR THE
SECOND HALF OF THE WEEK AS THE HIGH PRESSURE WEAKENS.
INSIDE: SEA BREEZES CONTINUE TO BE THE PRIMARY CONCERN FOR THE INNER
CHANNELS OVER THE NEXT 48 HOURS. REPORTED WINDS SPEEDS HAVE BEEN
GETTING UP TO AROUND 10 TO 20 KTS IN THE USUAL TROUBLE SPOTS, NEAR
POINT COUVERDEN, THE TIGHTER SPOTS IN STEPHEN'S PASSAGE, AND IN
SOUTHERN CHATHAM STRAIT. WINDS SHOULD CALM DOWN DURING THE OVERNIGHT
AND STAY LIGHTER INTO WEDNESDAY MORNING BEFORE PICKING BACK UP
AGAIN FOR WEDNESDAY AFTERNOON. WIND SPEEDS LOOK TO DECREASE FOR
THE SECOND HALF OF THE WEEK AS THE HIGH PRESSURE WEAKENS.
AJK WATCHES/WARNINGS/ADVISORIES
PUBLIC...HEAT ADVISORY UNTIL 7 PM AKDT THIS EVENING FOR AKZ319-325.
MARINE...NONE.
SHORT TERM...GFS
LONG TERM...STJ
AVIATION...STJ
MARINE...GFS
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