570
FXAK67 PAJK 231431
AFDAJK
SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
531 AM AKST TUE DEC 23 2025
SYNOPSIS
KEY MESSAGES:
- WIDESPREAD COLD TEMPERATURES AND COLD WIND CHILLS LAST THROUGH
THE MIDDLE OF THE WEEK.
- INCREASING POTENTIAL FOR A PATTERN CHANGE FOR THE END OF THE
WEEK INTO THE WEEKEND.
- POTENTIAL FOR SNOW EVENT FOR THE CENTRAL AND NORTHERN PANHANDLE;
SOUTHERN PANHANDLE COULD SEE SNOW TURNING TO RAIN.
SHORT TERM
/THROUGH TUESDAY NIGHT/ THE COLDEST WEATHER OF THE
CURRENT COLD AIR OUTBREAK IS SHOWING ITS COLORS THIS MORNING.
TEMPERATURES HAVE DROPPED TO THE TEENS BELOW ZERO IN THE CHILKAT
VALLEY, MENDENHALL VALLEY, AND THE KLONDIKE HIGHWAY THIS MORNING
WHILE SUB-ZERO TEMPS ENCOMPASS MOST OF THE NORTHERN INNER
CHANNELS, ICY STRAIT CORRIDOR AND YAKUTAT IN WIND SHELTERED AREAS.
FARTHER SOUTH, TEMPS RISE INTO THE TEENS AND EVEN LOW 20S FOR
EXTREME SOUTHERN AREAS. THESE NUMBERS ARE A GOOD 20 TO 30 DEGREES
BELOW NORMAL FOR THIS TIME OF YEAR. THE COLD WEATHER IS EXPECTED
TO CONTINUE THROUGH THE SHORT RANGE PERIOD WITH MORE COLD
TEMPERATURES TONIGHT (NEGATIVE NUMBERS AGAIN IN WIND SHELTERED
PARTS OF THE NORTH). THE COLDEST TEMPERATURES SHOULD BE THIS
MORNING THOUGH AS 850 MB TEMPS SHOW A SLOW WARMING TREND INTO
WEDNESDAY. THE COLD WEATHER HEADLINES CONTINUE ACROSS THE AREA AS
A RESULT.
ALSO CONTINUING IS THE OUTFLOW WINDS. SKAGWAY AND DOWNTOWN JUNEAU
STARTED SHOWING GUSTS TO 60 MPH OVERNIGHT PROMPTING NEW HIGH WIND
WARNINGS FOR THOSE AREAS THIS MORNING. GALES ALSO CONTINUE IN THE
NORTHERN INNER CHANNELS WITH VERY LITTLE SIGN OF THEM LESSENING
UNTIL LATE TUESDAY NIGHT WHEN PRESSURE GRADIENTS ACROSS THE COAST
RANGE FINALLY START TO DIMINISH AS THE YUKON HIGH BEGINS TO
WEAKEN. UNTIL THEN COLD WIND CHILLS AND FREEZING SPRAY IN MARINE
AREAS WILL BE THE RESULTS THAT WILL LAST INTO TUESDAY NIGHT AT
LEAST.
LONG TERM
WE CONTINUE TO WATCH THE POTENTIAL FOR A
SLIGHT SHIFT IN THE WEATHER PATTERN THAT WOULD GIVE THE NEXT ROUND
OF SIGNIFICANT SNOW TO SOUTHEAST ALASKA ALONG.
THE LONG RANGE COMPUTER MODELS, BOTH DETERMINISTIC AND ENSEMBLES,
ARE TRYING TO PUT A A COUPLE LOW PRESSURE CENTERS IN THE NORTHERN
AND EASTERN GULF OF ALASKA LATER THIS WEEK. THE FIRST LOW 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 DECREASE A BIT BEGINNING
AROUND THE WEDNESDAY/THURSDAY TIME FRAME. WHEN THE LOW CONTINUES ITS
JOURNEY SOUTHEASTWARD THURSDAY INTO FRIDAY MORNING, THE PRESSURE
GRADIENT WOULD TIGHTEN UP AGAIN, ALLOWING FOR WIND SPEEDS TO PICK
BACK UP AHEAD OF THE NEXT LOW THAT IS FORECASTED TO MOVE NORTHEAST
INTO THE GULF. IN PARTICULAR, THE N-S GRADIENT WILL INCREASE ACROSS
THE NORTHERN HALF OF THE PANHANDLE AS THE LOW SLIDES TO THE SOUTH OF
THE PANHANDLE, BRINGING NEAR GALES DOWN LYNN CANAL THURSDAY. AS THE
LOW MOVES SOUTHEAST, BEFORE THE LARGER LOW APPROACHES FROM THE WEST
FRIDAY NIGHT, THERE WILL BE ANOTHER BRIEF LULL IN THE WINDS INTO
FRIDAY PARTICULARLY ALONG THE SOUTHERN PANHANDLE. WINDS BEGIN TO
PICK UP ACROSS THE ENTIRE PANHANDLE FRIDAY NIGHT INTO THE WEEKEND AS
THE STRONGER LOW APPROACHES, AND A GALE FORCE FRONT BEGINS TO MOVE
IN FROM THE SOUTHWEST. THESE SOUTHERLY WINDS MOVING INTO THE
PANHANDLE WILL ALLOW FOR SOME WARMING ACROSS THE PANHANDLE ALONGSIDE
BRINGING PRECIPITATION THROUGH FROM W TO E INTO THE START OF THE
WEEKEND.
AS FAR AS SNOW POTENTIAL, THE EURO AND GFS HAVE COME INTO GREATER
AGREEMENT OVER LOW TRACKS AND 500MB FLOW. THE CANADIAN HAS BECOME
THE OUTLIER. THE CURRENT FORECAST LEANS TOWARDS THE STORY THAT THE
EURO AND GFS TELL. THE BIGGEST DIFFERENCE IN THE CANADIAN IS THE
OVERALL POSITIONS OF THE UPPER LEVEL FLOW AND SURFACE LEVEL
PRESSURES WOULD KEEP THE COLD AIR IN PLACE LONGER, GIVING SOUTHEAST
ALASKA MUCH GREATER AMOUNTS OF SNOW. BUT THERE IS MORE CONFIDENCE ON
THE STORY IN THE EURO AND GFS, SO FOR NOW, THE FORECAST THINKING
LEANS HEAVILY ON THE EURO AND GFS.
MOISTURE AMOUNTS ARE HINTING AT LIGHT SNOW ON THURSDAY, WITH A BREAK
ON FRIDAY. FRIDAY NIGHT INTO THE WEEKEND IS LOOKING LIKE ANOTHER
SIGNIFICANT WEATHER EVENT THAT COULD PRODUCE SIGNIFICANT AMOUNTS OF
SNOW FOR PARTS OF SOUTHEAST ALASKA.
FOR THURSDAY INTO THURSDAY NIGHT, THE 75TH PERCENTILES ARE GIVING
THE AREA AROUND A TENTH TO ABOUT A THIRD OF AN INCH OF QPF, WITH THE
GREATER AMOUNTS IN THE EURO, WHICH WOULD GIVE AROUND 1 TO 4 INCHES
OF SNOW OVER 24 HOURS. GREATEST AMOUNTS ALONG THE COAST.
FOR FRIDAY INTO FRIDAY NIGHT, THE 75TH PERCENTILES ARE LESS THAN
PREVIOUS RUNS, GIVING THE AREA AROUND HALF INCH TO 1 INCH OF QPF,
WITH THE GREATEST AMOUNT ALONG THE COAST, WHICH WOULD GIVE UPWARDS
OF 10 INCHES OF SNOW OVER 24 HOURS IF IT ALL FALLS AS SNOW. THE 50TH
PERCENTILES ARE GIVING THE AREA AROUND A QUARTER INCH TO HALF INCH,
WHICH WOULD GIVE AROUND 4 TO 7 INCHES OF SNOW.
SATURDAY'S QPF IS EVEN GREATER WITH THE 50TH PERCENTILE AROUND ONE
TO TWO INCHES, WHICH WOULD GIVE OVER 12 INCHES OF SNOW AND THE 75TH
PERCENTILE IS WELL OVER 2 INCHES, WHICH WOULD BE WELL OVER 15 INCHES
OF SNOW IF IT ALL FALLS AS SNOW. THE ISSUE WITH SATURDAY'S SNOWFALL
FORECAST IS WARMER AIR ALOFT MAY SLIDE IN, WHICH WOULD LOWER TOTAL
SNOWFALL AMOUNTS AND SOME AREAS IN THE FAR SOUTH MAY EVEN SEE A
TOTAL SWITCH TO RAIN.
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. THE 50TH PERCENTILE IS A
MIDDLE-GROUND ESTIMATE. THURSDAY'S SNOW IS LOOKING LIKE A QUICK-HIT
OF LIGHT SNOW WITH A BREAK IN THE SNOW FOR FRIDAY. FRIDAY NIGHT INTO
THE WEEKEND WILL BE A CHALLENGING FORECAST WITH THE SURGE OF
MOISTURE AND WARMER AIR COMING UP FROM THE SOUTH. THE FARTHER SOUTH
YOU ARE, THE GREATER CHANCE OF SEEING A FULL TRANSITION TO RAIN. THE
FARTHER NORTH YOU ARE, THE GREATER CHANCE OF SEEING ANOTHER LONG
DURATION SNOW EVENT.
EITHER WAY, STAY TUNED INTO THE FORECAST BUT BE PREPARED FOR A SNOWY
WEEKEND.
AVIATION
WIDESPREAD VFR CONDITIONS REMAIN. ACROSS THE NORTHERN
PANHANDLE, CLEAR SKIES PERSIST, BARRING SOME UPPER LEVEL OCEAN
EFFECT CLOUDS WITH CIGS GREATER THAN 5K FEET. THE MOST NOTABLE
WEATHER ELEMENT IS THE OUTFLOW PATTERN FOR THE NORTHERN HALF THE
PANHANDLE, SO THE ONLY HAZARD WILL BE TURBULENCE OR LLWS. THE
MOUNTAIN WAVE OVER JUNEAU HAS RESTRENGTHENED, AND WILL AT POINTS
CAUSE PERIODS OF LLWS AND TURBULENCE IN THE VICINITY OF JUNEAU
AIRPORT IN PARTICULAR. THE SOUTHERN HALF OF THE PANHANDLE HAS A FEW
MORE CLOUDS FROM A SYSTEM RACING UP THROUGH BRITISH COLUMBIA. A FEW
FLURRIES MAY OCCUR AS A RESULT, BUT DON'T EXPECT SIGNIFICANT VIS
REDUCTIONS FROM THESE.
MARINE
INSIDE WATERS: STRONG OUTFLOW CONDITIONS STILL EXIST WITH GALES TO
45 KT DOWN LYNN CANAL AND TAKU INLET WHILE 25 TO 30 KT WINDS ARE
OBSERVED DOWN TO FIVE FINGERS AND CAPE DECISION. LITTLE CHANGE IN
THESE WINDS ARE EXPECTED THROUGH TUESDAY NIGHT, BUT THAT WILL
START TO CHANGE INTO WEDNESDAY. AT THAT POINT THE STRONG YUKON
HIGH WILL START TO WEAKEN DIMINISHING THE PRESSURE GRADIENT ALONG
THE COAST MOUNTAINS WHICH WILL ALLOW THE OUTFLOW TO DIMINISH AS
WELL. UNTIL THE WINDS DECREASE, WE ARE STILL DEALING WITH
FREEZING SPRAY ACROSS A WIDE AREA OF THE INNER CHANNELS (AREAS OF
HEAVY FREEZING SPRAY IN LYNN CANAL AND TAKU INLET) AND HIGH SEAS
IN THE NORTHERN AND CENTRAL INNER CHANNELS (UP TO 12 FT FROM LONG
DURATION HIGH WINDS ALONG A LONG LINEAR FETCH) THROUGH TUESDAY
NIGHT.
GULF WATERS: NORTHERLY OUTFLOW CONDITIONS CONTINUE BUT WITH
NOTICEABLE DECREASES IN WIND SPEEDS OUT OF THE USUAL OUTFLOW
AREAS (25 TO 30 KT AT MOST CURRENTLY). THE WINDS OUT OF CROSS
SOUND, THE PASSES EAST OF YAKUTAT, AND CHATHAM STRAIT HAVE
DIMINISHED COMPARED TO YESTERDAY AS THE PRESSURE GRADIENT FEEDING
THEM HAS CONCENTRATED MORE INLAND OVER THE LAST 24 HOURS. A SLOW
DECLINE IN SPEEDS IS EXPECTED OVER THE NEXT 24 HOURS AS PRESSURE
GRADIENTS CONTINUE TO CONCENTRATE MORE INLAND. OTHERWISE WINDS
ACROSS THE EASTERN GULF ARE MAINLY NORTHERLY 20 KT OR LESS AND ARE
EXPECTED TO REMAIN THAT WAY INTO WEDNESDAY. HIGHEST SEAS (UP TO 9
FT) AND ANY FREEZING SPRAY ARE FOCUSED ON THE OUTFLOW AREAS
CURRENTLY WHILE AREAS AWAY FROM THE OUTFLOW ARE SEEING LOWER SEAS
(UP TO 5 FT) AND NO FREEZING SPRAY. THIS IS EXPECTED TO IMPROVE
THROUGH THE NEXT 36 HOURS AS OUTFLOW WEAKENS ESPECIALLY WEDNESDAY.
AJK WATCHES/WARNINGS/ADVISORIES
PUBLIC...EXTREME COLD WARNING UNTIL 6 AM AKST WEDNESDAY FOR AKZ318.
HIGH WIND WARNING UNTIL 9 PM AKST THIS EVENING FOR AKZ318-325.
EXTREME COLD WARNING UNTIL 6 PM AKST THIS EVENING FOR AKZ319-323.
COLD WEATHER ADVISORY UNTIL 6 PM AKST THIS EVENING FOR AKZ320-
326>331.
COLD WEATHER ADVISORY UNTIL NOON AKST TODAY FOR AKZ321-332.
COLD WEATHER ADVISORY UNTIL 3 PM AKST THIS AFTERNOON FOR AKZ322.
COLD WEATHER ADVISORY UNTIL 9 AM AKST THIS MORNING FOR AKZ324.
EXTREME COLD WARNING UNTIL NOON AKST TODAY FOR AKZ325.
COLD WEATHER ADVISORY FROM NOON TODAY TO 6 PM AKST THIS EVENING
FOR AKZ325.
MARINE...HEAVY FREEZING SPRAY WARNING FOR PKZ011-012-031.
HEAVY FREEZING SPRAY WARNING FOR PKZ013.
HEAVY FREEZING SPRAY WARNING FOR PKZ021-032-034.
HEAVY FREEZING SPRAY WARNING FOR PKZ053.
GALE WARNING FOR PKZ012-013.
SMALL CRAFT ADVISORY FOR PKZ011-021-022-031>035-053-641>644-651-
661>664-671.
SHORT TERM...EAL
LONG TERM...GJS/CONTINO
AVIATION...GFS
MARINE...EAL
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