310
FXAK67 PAJK 211333
AFDAJK
SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
433 AM AKST SUN DEC 21 2025
SYNOPSIS
- WIDESPREAD COLD TEMPERATURES AND COLD WIND CHILLS LAST THROUGH
THE WEEKEND AND INTO NEXT WEEK.
- A TAKU WIND EVENT WILL BRING POTENTIALLY DAMAGING WIND GUSTS
65-75 MPH THIS SUNDAY FOR DOWNTOWN JUNEAU AND SOUTHERN DOUGLAS
ISLAND.
SHORT TERM
COLD WEATHER CONTINUES, WITH LITTLE CHANGE IN SIGHT
THROUGH THE NEXT FEW DAYS. THE UPPER LEVEL TROUGH ANCHORED OVER
THE AREA IS CONTINUING TO REDIRECT STORM SYSTEMS INTO THE WEST
COAST. AT GROUND LEVEL, DOWNSLOPING OVERNIGHT IN SOME AREAS HAS
RESULTED IN SOMEWHAT WARMER (ALBEIT STILL FRIGID) TEMPERATURES
THAN EXPECTED, BUT MANY MORE SHELTERED AREAS ARE STILL SEEING
TEMPERATURES REACH INTO THE SINGLE DIGITS OR BELOW ZERO. THIS
TREND WILL CONTINUE THROUGH SUNDAY AND MONDAY, AS A COLD AIR MASS
REMAINS ANCHORED OVER THE PANHANDLE. NORTHERLY OUTFLOW WINDS
ACROSS SE AK WILL BE JOINED BY A MORE LOCALIZED TAKU WIND EVENT
FOR DOWNTOWN JUNEAU ON SUNDAY AND LASTING THROUGH MONDAY MORNING
AS A MOUNTAIN WAVE DESCENDS TO THE SURFACE, BRINGING WIND GUSTS OF
UP TO 75 MPH.
IN THE GULF, COLD OUTFLOW WINDS INTERACTING WITH COMPARATIVELY
WARMER OCEAN WATERS ARE RESULTING IN MESOSCALE LEVEL CYCLOGENESIS
AND OCEAN EFFECT SNOW, BUT THESE SHOULD REMAIN OFFSHORE AND SLOWLY
MEANDER SOUTHWARD OVER THE NEXT FEW DAYS AS THE TROUGH AXIS MOVES
SE.
LONG TERM...TUESDAY THROUGH FRIDAY
FOR NEXT WEEK, WE'LL BE WATCHING THE POTENTIAL FOR A SLIGHT SHIFT
IN THE WEATHER PATTERN THAT COULD BRING THE NEXT ROUND OF SNOW TO
SOUTHEAST ALASKA ALONG WITH SOME MARGINALLY WARMER TEMPS.
THE LONG RANGE COMPUTER MODELS, BOTH DETERMINISTIC AND ENSEMBLES,
ARE TRYING TO PUT A LOW PRESSURE CENTER IN THE NORTHERN GULF OF
ALASKA IN THE SECOND HALF OF NEXT WEEK. THIS WOULD ALLOW FOR THE
FLOW TO SWITCH TO A MORE ONSHORE PATTERN, OR AT THE VERY LEAST A
WEAKER OUTFLOW. THIS WOULD WEAKEN THE PRESSURE GRADIENT OVER AREA,
ALLOWING FOR WIND SPEEDS TO WEAKEN A BIT BEGINNING AROUND THE
TUESDAY/WEDNESDAY TIME FRAME. IF/WHEN THE LOW CONTINUES ITS JOURNEY
EASTWARD, THE PRESSURE GRADIENT WOULD TIGHTEN UP AGAIN, ALLOWING FOR
WIND SPEEDS TO PICK BACK UP FOR THE LATER DAYS OF THE WEEK.
AS FAR AS SNOW POTENTIAL, THE EURO AND CANADIAN DEVELOP A LOW IN THE
NORTHERN GULF AS EARLY AS WEDNESDAY. THEIR RESPECTIVE ENSEMBLES
MIRROR THIS STORY. THE OUTLIER IS THE GFS. THE LATEST DETERMINISTIC
RUN KEEPS THE PANHANDLE DRY UNTIL LATE THURSDAY INTO FRIDAY. THE GFS
ENSEMBLE AVERAGE, HOWEVER, DEVELOPS A LOW THURSDAY WITH AN AVERAGED
LOW PRESSURE CENTER REMAINING IN THE GULF THROUGH THE WEEKEND.
FOR NOW, MOISTURE AMOUNTS ARE HINTING AT IF THE PANHANDLE SEES ANY
SNOW LATER NEXT WEEK, IT WOULDN'T BE TOO MUCH FOR WHAT IS NORMAL IN
SE AK UNTIL FRIDAY AND THE WEEKEND.
THE 75TH PERCENTILES FOR THE EURO AND GFS ENSEMBLES GIVE THE
PANHANDLE LESS THAN A TENTH OF AN INCH OF QPF FOR WEDNESDAY THROUGH
WEDNESDAY NIGHT, WHICH WOULD GIVE AROUND 1 TO 2 INCHES OF SNOW AT
MOST. FOR THURSDAY INTO THURSDAY NIGHT, THE 75TH PERCENTILES ARE
GIVING THE AREA AROUND A QUARTER TO JUST OVER A HALF INCH OF QPF,
WITH THE GREATER AMOUNTS IN THE GEFS, WHICH WOULD GIVE AROUND 3 TO 7
INCHES OF SNOW OVER 24 HOURS. FOR FRIDAY INTO FRIDAY NIGHT, THE 75TH
PERCENTILES ARE GIVING THE AREA AROUND ONE TO TWO INCHES OF QPF,
WHICH WOULD GIVE UPWARDS OF 12+ INCHES OF SNOW OVER 24 HOURS. THE
50TH PERCENTILES ARE GIVING THE AREA AROUND A HALF INCH TO ONE INCH,
WHICH WOULD GIVE AROUND 6 TO 12 INCHES OF SNOW.
SO WHAT ARE THE MAIN TAKEAWAYS OFF ALL THIS DATA? FOR STARTERS, THE
75TH PERCENTILE IS AN UPPER BOUND. SO THE AMOUNTS MENTIONED ABOVE
ARE ON THE HIGH-END FOR CURRENT ESTIMATES. SECONDLY, SNOW IS
POSSIBLE AS EARLY AS WEDNESDAY BUT MAJORITY OF THE DATA IS POINTING
TO IT NOT BEING MUCH MUCH IF IT DOES HAPPEN. THURSDAY COULD BE A
WILDCARD DAY THAT IS WORTH WATCHING CLOSELY. FRIDAY AND NEXT WEEKEND
COULD BE A SNOWY FEW DAYS SO THAT WILL BE WORTH WATCHING CLOSELY,
ESPECIALLY WITH THE JUMP IN 75TH PERCENTILES FROM YESTERDAY TO
TODAY.
AS FAR AS THE SLIGHTLY WARMER TEMPS ARE CONCERNED, THERE IS A
WARMING TREND BUT MOST OF SOUTHEAST IS STILL LIKELY TO BE BELOW
FREEZING. TUESDAY'S HIGHS WILL BE GENERALLY IN THE SINGLE DIGITS TO
TEENS BUT BY FRIDAY, HIGHS COULD BE IN THE TEENS IN THE FAR NORTH,
20S AND 30S ELSEWHERE. FOR OVERNIGHT LOWS, MONDAY NIGHTS FORECASTED
LOWS ARE IN THE SINGLE DIGITS ABOVE AND BELOW ZERO WITH WARMER TEENS
TO 20S FOR FRIDAY NIGHT. SO WARMER BUT STILL COLDER-THAN-NORMAL.
AVIATION
WIDESPREAD OUTFLOW WINDS AND THE ASSOCIATED EFFECTS
ARE THE MAIN AVIATION CONCERNS FOR THE NEXT 24 HOURS. OVERNIGHT
THERE HAS BEEN AN OBSERVED INCREASE IN OUTFLOW WINDS ACROSS THE
NORTH WITH SOME OUTFLOW AREAS REACHING 45 KT FOR GROUND LEVEL
WINDS. IT IS THE SAME STORY NEAR THE MOUNTAIN TOPS ACROSS THE
CENTRAL AND NORTHERN PANHANDLE WITH WINDS AROUND 1000 TO 3000 FT
ASL REACHING 20 TO 40 KT FROM THE NE. THIS IS LEADING TO AREAS OF
TURBULENCE AS WELL AS AREAS OF LOW LEVEL WIND SHEAR, ESPECIALLY IN
AREAS WHERE SEA LEVEL WINDS ARE BLOCKED FROM THE OUTFLOW AND ARE
MOSTLY LIGHT. THESE WINDS ARE EXPECTED TO STAY RELATIVELY HIGH
THROUGH TONIGHT BEFORE DIMINISHING MONDAY MORNING SO THE
TURBULENCE AND LOW LEVEL WIND SHEAR CONCERNS REMAIN RELEVANT INTO
TONIGHT. OTHERWISE MOST OF THE PANHANDLE HAS VFR CONDITIONS WITH
THE SOUTHERN AND CENTRAL PANHANDLE UNDER A MID TO HIGH LEVEL CLOUD
DECK (4500 FT TO 11000 FT CEILINGS). THERE ARE SOME OCCASIONAL
MVFR CEILINGS SHOWING UP FROM FREDERICK SOUND SOUTHWARD THIS
MORNING, BUT THEY ARE SHORT LIVED AND THE OVERALL CLOUD COVER IS
EXPECTED TO CLEAR OUT MORE AS THE DAY GOES ON.
MARINE
INSIDE WATERS: OUTFLOW CONDITIONS REMAIN THROUGH THE WEEKEND,
WITH GALE FORCE WINDS FROM THE NORTH DOWN LYNN CANAL, GLACIER BAY,
STEPHENS PASSAGE, THROUGH ICY STRAIT, AND THEN OUT OF CROSS SOUND
ALONGSIDE FREEZING SPRAY. THIS STRONG EAST TO WEST GRADIENT WILL
ALSO ALLOW STRONG BREEZES TO NEAR GALES COMING OUT OF THE STIKINE
RIVER INTO SUMNER STRAIT.
EXPECT STRONG GALES OF 40 TO 47 KTS INTO LYNN CANAL AND NEAR
POINT COUVERDEN. ELDRED ROCK AND AREAS AROUND POINT COUVERDEN ARE
ALREADY SEEING SUSTAINED WINDS BACK TO 40 KTS WITH GUSTS UP TO 50
KTS. WINDS ACROSS OTHER NORTH TO SOUTH FACING CHANNELS, CHATHAM
STRAIT AND STEPHENS PASSAGE, AND OUT OF CROSS SOUND, WILL INCREASE
AGAIN TO NEAR GALES TO GALE FORCE WINDS, 28 TO 40 KTS. FULLY
DEVELOPED SEAS EXPECTED DOWN LYNN CANAL AND STEPHENS PASSAGE
CONTINUE DURING THIS WHOLE OUTFLOW PERIOD, WITH THE HIGHEST SEAS
OF 14 TO 16 FT. WIDESPREAD FREEZING SPRAY FOR MANY CHANNELS WILL
CONTINUE, WITH HEAVY FREEZING SPRAY FOR GLACIER BAY, LYNN CANAL,
ICY STRAIT, NORTHERN CHATHAM, AND STEPHEN'S PASSAGE IN
PARTICULAR.
SOME MODELS ARE POINTING AT A WEAKENING PRESSURE GRADIENT MID TO
LATE WEEK NEXT WEEK. THIS WOULD ALLOW FOR A BREAK IN OUTFLOW
CONDITIONS WITH DIMINISHING WINDS. BEHIND THAT COUPLE DAY BREAK, THE
GRADIENT WILL LIKELY STRENGTHEN ONCE AGAIN. WE WILL CONTINUE TO
MONITOR THIS POTENTIAL BREAK FROM THESE STRONG OUTFLOW WINDS.
OUTSIDE: OFFSHORE FLOW CONTINUES, BRINGING INCREASED GAP WINDS INTO
THE NE GULF COAST AND STRONGER NE OUTFLOW WINDS COMING OUT OF CROSS
SOUND INTO THE GULF WATERS. OUTFLOW GAP WINDS COMING OFF THE NE GULF
COAST CONTINUE TO INCREASE TO GALE FORCE TO STRONG GALES ALONG THE
OUTER COASTLINE, TO THE EAST OF YAKUTAT DOWN TO CAPE SPENCER. AS
WELL AS INCREASE WIND SPEEDS, WAVE HEIGHTS ONCE AGAIN BUILD TO
BETWEEN 10 AND 16 FT SATURDAY EVENING INTO SUNDAY, WITH THE HIGHEST
SEAS EXPECTED IN THE NORTHERN GULF WATERS. SEA SPRAY HAS ALSO
DEVELOPED OVER THE NE GULF. WITH COLD TEMPERATURES, AND SEA SURFACE
TEMPERATURES BELOW 45 DEGREES F, THIS SEA SPRAY IS LIKELY TO BE
FREEZING SPRAY. SOME PARTS OF THE OUTER COASTAL WATERS WILL LIKELY
EXPERIENCE OCEAN EFFECT SNOW SHOWERS AS THE COLDER OUTFLOW WINDS
INTERACT WITH THE (COMPARATIVELY) WARMER WATERS OF THE GULF.
OUTFLOW WINDS BEGIN TO DIMINISH LATER MONDAY INTO THE START OF THE
WEEK. THEN, MID TO LATE WEEK A MORE ORGANIZED LOW PRESSURE SYSTEM
MOVES INTO THE GULF ONCE AGAIN INCREASING GULF WINDS.
AJK WATCHES/WARNINGS/ADVISORIES
PUBLIC...EXTREME COLD WARNING UNTIL NOON AKST MONDAY FOR AKZ317>322-
325>327.
COLD WEATHER ADVISORY UNTIL NOON AKST MONDAY FOR AKZ323-328>332.
COLD WEATHER ADVISORY UNTIL MIDNIGHT AKST TONIGHT FOR AKZ324.
EXTREME COLD WARNING FROM MIDNIGHT TONIGHT TO NOON AKST MONDAY
FOR AKZ324.
HIGH WIND WARNING UNTIL 9 AM AKST MONDAY FOR AKZ325.
MARINE...HEAVY FREEZING SPRAY WARNING FOR PKZ011>013-021-031>033-053-644-
651.
HEAVY FREEZING SPRAY WARNING FOR PKZ022.
HEAVY FREEZING SPRAY WARNING FOR PKZ022.
HEAVY FREEZING SPRAY WARNING FOR PKZ034.
HEAVY FREEZING SPRAY WARNING FOR PKZ671.
STORM WARNING FOR PKZ643-644-651-663.
GALE WARNING FOR PKZ011>013-022-031-032-053-642-662-664-671-672.
SMALL CRAFT ADVISORY FOR PKZ021-033>036-641-652-661.
SHORT TERM...GFS
LONG TERM...GJS
AVIATION...EAL
MARINE...GFS/EAB
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