410
FXAK67 PAJK 091753
AFDAJK
SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
953 AM AKDT SUN AUG 9 2026
SYNOPSIS
KEY MESSAGES:
-SUICIDE BASIN GLACIER DAMMED LAKE CONTINUES TO FILL, 1342 FT AS
OF THIS MORNING. AT THIS TIME, IT IS EXPECTED TO BE FULL SOMETIME
AUGUST 10TH OR 11TH. IN THE PAST, IT HAS TAKEN UP TO 6 DAYS FOR
THE MAIN FLOODING EVENT TO START AFTER THE BASIN IS FULL. VISIT
WEATHER.GOV/AJK/SUICIDEBASIN FOR MORE INFORMATION.
-NO MAJOR WEATHER CONCERNS EXPECTED INTO EARLY NEXT WEEK. PERIODS
OF LIGHT RAIN AND OVERCAST SKIES CONTINUE THROUGH SUNDAY. HIGHS
REACH INTO THE MID TO UPPER 60S SUNDAY AND MONDAY.
-MARINE LAYER LOW CLOUDS WILL PERSIST OVER THE EASTERN GULF AND
INNER CHANNELS THROUGH THE WEEKEND.
SHORT TERM
/THROUGH MONDAY NIGHT/ HIGH PRESSURE CONTINUES TO
SIT OVER THE GULF BUT CONDITIONS LOOK TO OVERALL IMPROVE AS WE
START A NEW WEEK. MID LEVEL ATMOSPHERIC WINDS ARE EXPECTED TO
SHIFT TO OFFSHORE FLOW THROUGH THE DAY SUNDAY, CLEARING UP ANY
LINGERING SHOWERS ACROSS THE PANHANDLE BY THE MORNING AND MARKING
THE ONSET OF A DRYING TREND. THIS SHIFT IS EXPECTED TO BRING A
WARMER AIRMASS IN FROM CANADA AS WELL AS CLEARER SKIES TO THE
SOUTHERN PANHANDLE WITH BREAKS IN THE CLOUDS ACROSS THE NORTH.
BOTH OF THESE FACTORS ARE LIKELY TO WARM UP THE PANHANDLE ACROSS
THE BOARD, WITH HIGHS IN THE MID TO HIGH 60S ON MONDAY AND
REACHING INTO THE LOW 70S BY TUESDAY, THOUGH, CLOUD COVER WILL BE
A LARGE DETERMINING FACTOR IN THIS HEATING.
ALTHOUGH MUCH OF THE PANHANDLE IS EXPECTED TO REMAIN DRY THROUGH
THE PERIOD, SOME CONVECTIVE AND TERRAIN INDUCED SHOWERY ACTIVITY
IS EXPECTED AT THE CANADIAN BOARDER AROUND HAINES AND SKAGWAY
DURING THE DAYTIME HOURS. MODELS ARE PICKING UP ON POCKETS OF RAIN
AS FAR SOUTH AS THE ICE FIELD IN THE MOUNTAINS NEAR JUNEAU AS
WELL AS HEIGHTENED CONVECTIVE PARAMETERS SUCH AS SURFACE CAPE.
THUNDERSTORM ACTIVITY IS MORE LIKELY TO OCCUR AROUND DALTON CACHE
AND WHITE PASS AND IS NOT EXPECTED TO REACH ALL THE WAY TO HAINES
AND SKAGWAY. ANY CONVECTIVE ACTIVITY IN HAINES AND SKAGWAY, OR
OUT THEIR RESPECTIVE HIGHWAYS, IS LIKELY TO BE LATER IN THE
AFTERNOON OR EVENING, AROUND OR AFTER THE TIME THAT TEMPERATURES
PEAK ON SUNDAY AND POSSIBLY MONDAY. DUE TO THE EASTERLY FLOW, IT
IS NOT ENTIRELY OUT OF THE QUESTION THAT JUNEAU COULD SEE SOME
LIGHT SHOWERS IN THE OVERNIGHT HOURS AS THEY MOVE OFF THE ICE
FIELD.
LONG TERM
/TUESDAY THROUGH FRIDAY/ THE CURRENT EXPECTATION
REMAINS FOR MAIN FRONTAL PRECIPITATION TO PUSH THROUGH ON TUESDAY
WITH A MEAN 24 HOUR RAINFALL ACCUMULATION OF 0.20” MAINLY AT
HIGHER ELEVATIONS, WITH 0.10” MORE LIKELY OVER LOCATIONS AT SEA
LEVEL. INTERMITTENT EASTERLY WAVES MAY PROVIDE ADDITIONAL LIGHT
RAIN PERIODICALLY THROUGH THE WEEK FOR THE CENTRAL TO NORTHERN
REGIONS, THOUGH PROBABILITIES DECREASE AS THE SURFACE HIGH
PRESSURE OVER THE PANHANDLE STRENGTHENS FROM WEDNESDAY ONWARD. AS
THE MIDWEEK SYSTEM DEPARTS, CLEARING SKIES ACROSS THE CENTRAL AND
SOUTHERN PANHANDLE WILL DRIVE A WARMING TREND, SUPPORTED BY 850MB
TEMPERATURE ANOMALIES REACHING APPROXIMATELY 4 TO 5 DEG C ABOVE
SEASONAL NORMS. THE EXTREME FORECAST INDEX (EFI) HIGHLIGHTS THIS
TREND BEGINNING WEDNESDAY AND CONTINUING THROUGH FRIDAY,
PARTICULARLY AT HIGHER ELEVATIONS AND BROADLY ACROSS THE PANHANDLE
AS THE UPPER LEVEL RIDGE SETTLES IN. HIGH TEMPERATURES ARE LIKELY
TO REACH THE LOW TO MID 70S, WITH SOME INLAND AND SOUTHERN AREAS
POTENTIALLY NEARING HEAT ADVISORY THRESHOLDS (80 DEG F) AS SKIES
CLEAR TOWARD THE WEEKEND. FINALLY, WINDS ARE EXPECTED TO REMAIN
LIGHT THROUGHOUT THE PERIOD, THOUGH DIURNAL SEA BREEZES WILL
LIKELY INCREASE IN RESPONSE TO WARMER SURFACE TEMPERATURES AND A
SHIFT TO WEAK WNW ONSHORE FLOW BY FRIDAY.
AVIATION
/THROUGH 18Z MONDAY/ UPPER LEVEL SYSTEM REMAINS
STATIONARY OVER THE PANHANDLE LATE THIS MORNING KEEPING A VARIETY
OF FLIGHT CONDITIONS ACROSS THE AREA WITH CIGS AOB 3500 FT ACROSS
THE NORTHERN PANHANDLE WITH THE LOWEST CONDITIONS AROUND ICY
STRAIT AND CROSS SOUND, AND AOB 1000FT ALONG THE SOUTHERN COAST
LINE. WITH THE SURFACE HIGH PARKED OVER THE CENTRAL GULF IN
TANDEM WITH THE UPPER LEVEL LOW, OVERCAST SKIES AND UNSETTLED
WEATHER WILL CONTINUE THROUGH THE TAF PERIOD THOUGH PROBABILITY OF
SHOWERS REACHING THE PANHANDLE REMAINS LOW. CONDITIONS IMPROVE
DURING THE AFTERNOON TO VFR/MVFR WITH CIGS AOA 4000FT, HOWEVER
DIMINISH ROUTINELY OVERNIGHT AOB 2000FT AS MARINE LAYER SETTLES IN
AND LIGHT RAIN RETURNS.
SIMILAR TO PREVIOUS DAYS, WINDS ARE EXPECTED TO INCREASE IN THE
COMING HOURS REACHING SUSTAINED 10 TO 15KTS THIS AFTERNOON, CAN'T
RULE OUT A GUST UP TO 20KTS UNDER ANY SEABREEZE INFLUENCES,
PARTICULARLY NEAR TAIYA INLET. NO LLWS CONCERNS THROUGH THE TAF
PERIOD.
MARINE
OUTSIDE: A 1023MB HIGH PRESSURE REMAINS STATIONARY OVER THE
CENTRAL GULF THROUGH SUNDAY AND INTO EARLY NEXT WEEK, KEEPING
OVERCAST SKIES WITH LIGHT AND VARIABLE WINDS ALONG IN THE OUTER
WATERS. WAVE HEIGHTS REMAIN LARGELY BENIGN THROUGH THE EARLY WEEK,
AROUND 4FT OR LESS ALONG THE COAST. ACCOMPANYING THIS HIGH
PRESSURE IS BROAD WESTERLY TO NORTHWESTERLY WINDS IN THE NE GULF
COAST DOWN TO DIXON ENTRANCE AROUND 10 TO 15 KTS OR LESS. MAIN
MARINE CONCERN FOR OUTER AND COASTAL WATERS WILL BE NIGHTLY RETURN
OF MARINE LAYER, DROPPING VISIBILITIES POTENTIALLY AS LOW AS ONE
QUARTER MILE EACH MORNING.
INSIDE: CONDITIONS ACROSS THE INNER WATERS REMAIN CALM THIS
MORNING, WITH CLOUDY SKIES ACROSS THE NORTHERN PANHANDLE WITH SOME
CLEARING GOING ON ACROSS THE SOUTH, WINDS LARGELY 10 KTS OR LESS,
UP TO 15 KTS NEAR ROCKY ISLAND. NO REAL DRIVING FORCE FOR WINDS
THROUGH SUNDAY, OUTSIDE OF THE USUAL DAILY SEA BREEZE, BUT WILL
LIKELY SEE STRONGEST WINDS IN LYNN CANAL NORTHWARD TO TAIYA INLET
WITH SUSTAINED SOUTHERLY WINDS 10 TO 15KTS. WAVE HEIGHTS REMAIN 4
FEET OR LESS THROUGH EARLY WEEK.
HYDROLOGY
SUICIDE BASIN CONTINUES TO FILL THIS MORNING, RISING TO AROUND
1341 FT AS OF 4AM AKDT. THE LASER GAGE IN THE BASIN CONTINUES TO
SHOW A STEADY INCREASING TREND DESPITE A 4 FT DROP IN THE DATA
FROM THE CALVING EVENT ON SATURDAY DUE TO THE SHIFTING ICE AND
WAVES. OVERALL MESSAGE CONTINUES TO BE THE SAME, EXPECTING THE
BASIN TO BE FULL MOST LIKELY AROUND AUGUST 10TH OR 11TH. IN THE
PAST, IT HAS TAKEN UP TO 6 DAYS FOR THE MAIN FLOODING EVENT TO
START AFTER THE BASIN IS FULL.
VISIT WEATHER.GOV/AJK/SUICIDEBASIN FOR MORE INFORMATION.
AJK WATCHES/WARNINGS/ADVISORIES
PUBLIC...NONE.
MARINE...NONE.
SHORT TERM...AGP
LONG TERM...BAS
AVIATION...NM/STJ
MARINE...NM
HYDROLOGY...NM
VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU
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