792
FXAK68 PAFC 251421
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
521 AM AKST THU DEC 25 2025
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3/CHRISTMAS
DAY THROUGH SATURDAY NIGHT)...
KEY POINTS:
* GUSTY GAP WINDS ALONG THE COAST HAVE PEAKED AND WILL GRADUALLY
WEAKEN TODAY THROUGH TONIGHT. THIS INCLUDES SEWARD, WHITTIER,
AND VALDEZ AND BORDERING COASTAL WATERS.
* WIDESPREAD LIGHT SNOW WILL RETURN TO SOUTHCENTRAL FRIDAY THROUGH
FRIDAY NIGHT. WHILE SNOW ACCUMULATION WILL GENERALLY BE LIGHT
(1 TO 3 INCHES FOR MOST AREAS), THERE IS HIGH POTENTIAL FOR
REDUCED VISIBILITIES ALONG AREA ROADWAYS AS LIGHT AND FLUFFY
SNOW IS EASILY LOFTED AND BLOWN AROUND BE THE MOVEMENT OF
VEHICLES.
* KODIAK ISLAND WILL SEE SNOW DEVELOP TONIGHT, TRANSITION TO RAIN
FRIDAY, THEN GO BACK TO SNOW LATE FRIDAY NIGHT OR SATURDAY.
THERE IS POTENTIAL FOR HEAVY SNOW AND BLOWING SNOW SATURDAY
DEPENDING ON THE PROXIMITY OF A LOW TRACKING EAST OF KODIAK
ISLAND.
* THE REGION WILL DRY OUT THIS WEEKEND AS A REINFORCING SHOT OF
COLD AIR AND WINDS ARRIVES. THE MATANUSKA VALLEY WILL LIKELY SEE
ANOTHER ROUND OF STRONG WINDS, THOUGH AT THIS POINT IT DOES NOT
LOOK AS STRONG AS PREVIOUS WIND EVENTS THIS MONTH. STAY TUNED AS
WE CONTINUE TO MONITOR THE STRENGTH OF WINDS.
THE STRONG BLOCKING RIDGE WHICH HAS BEEN FIRMLY ENTRENCHED OVER
THE BERING SEA FOR MUCH OF DECEMBER HAS WEAKENED AND SHIFTED
SOUTH. THIS WILL LEAD TO WHAT LOOKS TO BE A TEMPORARY CHANGE IN
THE PATTERN. FIRST OFF, A STRONG SHORT-WAVE WHICH CROSSED
SOUTHCENTRAL OVERNIGHT IS NOW EXITING TOWARD SOUTHEAST ALASKA.
STRONG AND GUSTY GAP WINDS ALONG THE COAST HAVE PEAKED AND WILL
GRADUALLY DIMINISH TODAY THROUGH TONIGHT AS THE UPPER RIDGE BUILDS
IN FROM THE WEST. WITH LIGHT WINDS INLAND, TEMPERATURES WILL
BOTTOM OUT ONCE AGAIN TONIGHT INTO SATURDAY - FALLING BELOW ZERO
FOR MUCH OF THE REGION.
A SERIES OF SHORT-WAVES AREA TRACKING UP AND OVER THE UPPER RIDGE,
FROM THE NORTH-CENTRAL PACIFIC TO THE ALEUTIANS. THESE WILL CAUSE
THE UPPER RIDGE, WHICH IS CURRENTLY CENTERED OVER THE EASTERN
BERING, TO SHIFT EASTWARD AND FLATTEN. MEANWHILE, AN ARCTIC TROUGH
WILL DIG SOUTHEASTWARD ACROSS THE NORTHERN BERING SEA AND PHASE
WITH A TROUGH IN THE SOUTHERN BERING SEA LATE TONIGHT. THIS
NORTHERN SHORT-WAVE WILL KEEP THE STORM TRACK FAIRLY FAR SOUTH,
WITH MOST OF THE SURFACE LOWS REMAINING SOUTH OF THE ALASKA
PENINSULA AND KODIAK ISLAND. THIS IS SIGNIFICANT BECAUSE IT WILL
LIMIT THE EXTENT OF WARMING FOR SOUTHERN ALASKA. DESPITE A FAIRLY
COMPLEX SET OF FEATURES, MODEL GUIDANCE IS IN GOOD AGREEMENT WITH
MOST FEATURES AND FORECAST CONFIDENCE IS RELATIVELY HIGH.
THE FORECAST FOR KODIAK ISLAND MAY BE THE BIGGEST CHALLENGE.
EXPECT A ROUND OF SNOW TONIGHT, A TRANSITION TO RAIN FRIDAY AS
EAST TO NORTHEAST WINDS INCREASE AHEAD OF A SURFACE LOW TRACKING
SOUTH OF THE ISLAND. THERE IS SOME SPREAD IN LOW TRACK AND
KODIAK'S WINDS AND SURFACE TEMPERATURES ARE VERY SENSITIVE TO
SLIGHT CHANGES IN THE TRACK. THE BIG QUESTION IS HOW WARM DO THEY
GET FRIDAY AFTERNOON AND EVENING AND WHEN DOES THE AIRMASS COOL
ENOUGH BEHIND THE LOW TO CAUSE A CHANGE BACK TO SNOW. THE
AFOREMENTIONED ARCTIC TROUGH LAGS WAY BEHIND. HOWEVER, THERE WILL
BE SOME COOLING BY EARLY SATURDAY AS THE WIND BACKS TOWARD THE
NORTH. THERE IS POTENTIAL FOR HEAVY SNOW AND BLOWING SNOW, BUT
RIGHT NOW GUIDANCE WOULD SUGGEST TEMPERATURES MAY BE TOO WARM ON
SATURDAY TO CAUSE SIGNIFICANT ACCUMULATION OR VISIBILITY
REDUCTIONS. OF COURSE, PERSISTENT HEAVIER SNOWFALL CAN CAUSE
SURFACE TEMPERATURES TO QUICKLY DROP TO FREEZING. NO MATTER WHAT,
EXPECT TRAVEL IMPACTS ON KODIAK ISLAND.
FORECAST CONFIDENCE IS HIGHER FOR WIDESPREAD LIGHT SNOWFALL ACROSS
SOUTHCENTRAL, DEVELOPING DURING THE DAY FRIDAY AND CONTINUING
FRIDAY NIGHT INTO SATURDAY. THE OVERALL FORCING MECHANISMS FOR
SNOW ARE WEAK, LARGELY DRIVEN BY WARM AIR OVERRIDING COLD AIR.
HOWEVER, LOOKING AT FORECAST SOUNDINGS ACROSS SOUTHCENTRAL, IT
LOOKS FAVORABLE FOR A DEEP LAYER OF DENDRITIC SNOW CRYSTAL
GROWTH, WHICH FAVORS MORE SNOW ACCUMULATION. BASED ON THIS, HAVE
TRENDED UPWARD WITH SNOW ACCUMULATION ACROSS THE BOARD. STILL,
AS FAR AS SNOW EVENTS GOES, THIS WILL STILL BE FAIRLY MINOR WITH
1 TO 3 INCHES FOR MOST AREAS. SNOW INTENSITY DOES LOOK HEAVIER FOR
MUCH OF THE KENAI PENINSULA, POSSIBLY MORE ON THE ORDER OF 2 TO 6
INCHES. THE BIGGEST CONCERN HOWEVER, IS LOW DENSITY SNOW WILL BE
EASILY LOFTED AND BLOWN AROUND. THUS, THERE COULD BE WIDESPREAD
IMPACTS TO TRAVEL ALONG AREA ROADWAYS. STRENGTHENING NORTHERLY
WINDS OUT AHEAD OF THE APPROACHING SURFACE LOW COULD LEAD TO
WHITE-OUT CONDITIONS IN SOME AREAS. AT THIS POINT, THE MOST
SIGNIFICANT WINDS LOOK TO BE ALONG COOK INLET FROM NIKISKI TO
ANCHOR POINT. STAY TUNED AS WE CONTINUE TO REFINE THE FORECASTS
AND WEATHER IMPACTS.
THE ORIGINAL ARCTIC TROUGH STALLS TO THE WEST ON FRIDAY. HOWEVER,
ANOTHER ARCTIC SHORT-WAVE DIGS SOUTHWARD ACROSS MAINLAND ALASKA
FRIDAY AND INTO SOUTHCENTRAL SATURDAY. THIS WILL HELP BRING AN END
TO PRECIPITATION FOR MOST OF THE REGION, WHILE ALSO BRINGING YET
ANOTHER ROUND OF COLD AIR ADVECTION WINDS. MODELS VARY IN THE
POSITION OF THE TROUGH OVER SOUTHCENTRAL THIS WEEKEND, THOUGH THEY
ALL STALL OR RETROGRADE THE TROUGH AS ENERGY MOVES OUT OF THE
NORTHEAST PACIFIC AND INTO THE GULF. AT THIS POINT, THE PATTERN
DOES NOT LOOK IDEAL FOR ANOTHER HIGH WIND EVENT IN THE MATANUSKA
VALLEY, BUT IT WILL BE WINDY NONETHELESS. WE WILL CONTINUE TO
CLOSELY MONITOR THIS, AS ANY SHIFT IN THE UPPER TROUGH WILL AFFECT
THE STRENGTH AND DISTRIBUTION OF WINDS.
-SEB
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3: TODAY THROUGH SATURDAY)...
THE FORECAST REMAINS FAIRLY ON TRACK, THOUGH THERE HAVE BEEN
MAJOR CHANGES TO THE PRODUCTS IN EFFECT. HERE ARE THE WATCHES,
WARNINGS, AND ADVISORIES NOW IN EFFECT:
* NEW: BLIZZARD WARNING FOR NORTHERN BRISTOL BAY COAST
* NEW: BLIZZARD WARNING FOR EASTERN ALEUTIANS
* UPDATED TIME: START TIME FOR PRIBILOF ISLANDS' BLIZZARD WARNING
HAS BEEN PUSHED BACK TO 11 PM TONIGHT
* NEW: WINTER WEATHER ADVISORY FOR SOUTHERN ALASKA PENINSULA,
NORTHERN ALASKA PENINSULA, KUSKOKWIM DELTA, AND WESTERN CAPES
* WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR GREATER BRISTOL
BAY
SINCE THE PREVIOUS FORECAST PACKAGE, THE LOW RESPONSIBLE FOR ALL
THIS HAZARDOUS WINTER WEATHER HAS TAKEN A FURTHER NORTH TRACK.
THIS MEANS THAT WARM AIR AND PRECIPITATION WILL LIKELY MOVE
FURTHER NORTH THAN INITIALLY FORECAST, WHICH HAS BEEN THE IMPETUS
FOR THE UPDATED START TIME FOR THE PRIBILOF ISLANDS BLIZZARD
WARNING AND THE ISSUANCE OF NEW WINTER WEATHER ADVISORIES FOR
KUSKOKWIM DELTA. WITH THE LOW CONTINUING TO TREND FURTHER NORTH
WITH THE LATEST MODEL RUNS, IT'S POSSIBLE THAT MORE CHANGES ARE
FORTHCOMING. IN ADDITION, WE CONTINUE TO MONITOR THE POTENTIAL FOR
CENTRAL ALASKA PENINSULA (PORT HEIDEN AREA) TO SEE SIGNIFICANT
VISIBILITY REDUCTIONS IN BLOWING SNOW. CURRENTLY, PORT HEIDEN IS
NOT UNDER A WINTER WEATHER ADVISORY BECAUSE THE STRONGEST WINDS
WILL BE TO ITS SOUTH AND WEST, WHILE THE HEAVIEST SNOW WILL BE TO
ITS NORTH AND EAST. STILL, CONDITIONS ARE BORDERLINE. STAY TUNED
TO THE FORECAST.
THE PREVIOUS FORECAST DISCUSSION STILL STANDS AND HAS BEEN COPIED
BELOW WITH LIGHT EDITS:
HIGH PRESSURE EXTENDING FROM THE NORTHERN BERING SEA ACROSS
SOUTHWEST ALASKA INTO THE NORTH PACIFIC WILL MOVE OUT OF THE
REGION TO THE EAST AS LOW PRESSURE CENTERED SOUTH OF THE ALEUTIANS
THIS EVENING TRACKS INTO THE BERING SEA FOR TODAY (CHRISTMAS
DAY). THE LOW TRACK HAS SHIFTED SOMEWHAT NORTHWARD, WHICH BRINGS
WARMER AIR TO THE PRIBILOF ISLANDS, WHERE PRECIPITATION IS NOW
FORECAST TO BE PRIMARILY RAIN THROUGH THIS AFTERNOON. A STRONG
COLD FRONT WILL CAUSE TEMPERATURES TO DROP TONIGHT, CAUSING A
DEFINITE SHIFT TO SNOW FOR THE PRIBILOFS AS NORTH TO NORTHEASTERLY
WINDS STRENGTHEN, GUSTING AS HIGH AS 60-70 MPH. BLIZZARD
CONDITIONS ARE THEREFORE FORECAST UNTIL SNOWFALL COMES TO A
RELATIVELY QUICK END FROM NORTH TO SOUTH ON FRIDAY.
FURTHER EAST, SNOW PUSHES INTO SOUTHWEST ALASKA TONIGHT FROM WEST
TO EAST. APPRECIABLE SNOW TOTALS ARE EXPECTED FROM THIS,
ESPECIALLY CLOSE TO THE BRISTOL BAY COAST FROM TONIGHT INTO
SATURDAY. SNOW AMOUNTS WILL RANGE FROM AROUND 4 TO 12 INCHES FOR
BRISTOL BAY AND THE ALASKA PENINSULA, WITH LOWER AMOUNTS POSSIBLE
FOR PORTIONS OF THE KUSKOKWIM DELTA. THERE IS MORE UNCERTAINTY
FURTHER SOUTH ALONG THE ALASKA PENINSULA GIVEN TRACK/TIMING
DIFFERENCES WHICH WILL DETERMINE HOW LONG PRECIPITATION WILL
REMAIN RAIN BEFORE TRANSITIONING OVER TO SNOW FRIDAY
AFTERNOON/EVENING WITH THE ARRIVAL OF THE SURGE OF COLD AIR. WINDS
INCREASE ACROSS SOUTHWEST ALASKA THROUGH THE DAY ON FRIDAY, WHICH
WILL CAUSE BLOWING SNOW TO LIMIT VISIBILITY. VISIBILITY IS LIKELY
TO IMPROVE SATURDAY AS SNOW GRADUALLY TAPERS OFF FROM NORTHWEST
TO SOUTHEAST. THERE IS HIGHER CONFIDENCE IN THE EASTERN ALEUTIANS
FOR THE POTENTIAL OF BLIZZARD CONDITIONS WITH WINDS INCREASING TO
GUST AROUND 60-70 MPH, THOUGH SNOW AMOUNTS ARE LIKELY TO BE LOWER
THERE, WITH THE EXCEPTION OF UNALASKA/DUTCH HARBOR. OVER THE
EASTERN BERING SEA, STORM FORCE WINDS DEVELOP FRIDAY NIGHT. WINDS
LOOK TO PERSIST INTO THE WEEKEND, ONLY GRADUALLY DIMINISHING,
WHICH MAY CONTINUE TO LOFT SNOW AFTER PRECIPITATION ENDS ON
SATURDAY.
IN INTERIOR SOUTHWEST ALASKA, SPECIFICALLY PORTIONS OF THE
KUSKOKWIM DELTA AND LOWER KUSKOKWIM VALLEY, TEMPERATURES WILL BE
COLD, WITH WIND CHILLS/APPARENT TEMPERATURES DROPPING TO NEAR OR
BELOW 40 DEGREES BELOW ZERO BEGINNING FRIDAY NIGHT. ALONG THE
SOUTHWEST COAST, THE COLD AIR AND GALE TO STORM FORCE WINDS WILL
COMBINE TO PRODUCE A HEAVY TO EXTREME FREEZING SPRAY HAZARD THAT
LASTS INTO THE WEEKEND.
QUESADA/CHEN
LONG TERM FORECAST (DAYS 4 THROUGH 7: SUNDAY THROUGH WEDNESDAY)
AN AMPLIFIED UPPER LEVEL PATTERN SETS IN LATE THIS WEEK AS A
STRONG RIDGE BUILDS OVER THE ALEUTIANS AND BERING SEA WHILE A
TROUGH DIGS SOUTH ACROSS THE INTERIOR, SUPPORTING AN UPPER LEVEL
LOW CENTERED OVER THE WESTERN GULF. A SURFACE LOW LIFTING OUT OF
THE NORTH PACIFIC INTO THE GULF WILL TAKE ADVANTAGE OF THIS UPPER
LEVEL SUPPORT, BRINGING A RENEWED THREAT FOR HIGH WINDS AT THE END
OF THE WEEKEND FOR TYPICAL LOCATIONS INCLUDING THE MATANUSKA
VALLEY, VALDEZ AREA/THOMPSON PASS, AND ALONG THE SOUTHERN AKPEN
AND GULF COAST INTO EARLY NEXT WEEK. ALTHOUGH MOST PRECIPITATION
WILL BE PUSHED INTO SOUTHEAST ALASKA, SNOWFALL WILL LINGER IN THE
EASTERN COPPER RIVER VALLEY AND DELTA THROUGH EARLY NEXT WEEK AS
SURFACE LOW PRESSURE ROTATES IN THE EASTERN GULF.
FURTHER WEST, A TIGHTENING PRESSURE GRADIENT BETWEEN THE STRONG
RIDGE CENTERED OVER THE WESTERN BERING AND TROUGH OVER THE
MAINLAND WILL PROMOTE STRONG NORTH-NORTHEAST WINDS ACROSS THE
CENTRAL AND EASTERN ALEUTIANS ON SUNDAY. THE ARCTIC AIRMASS
ASSOCIATED WITH THIS TROUGH WILL KEEP TEMPERATURES BELOW AVERAGE
ACROSS SOUTHERN ALASKA, WITH THE COLDEST AREAS BEING THE COPPER
RIVER BASIN AND INTERIOR SOUTHWEST ALASKA, WHERE AMBIENT
TEMPERATURES WILL HOVER IN THE RANGE OF 20 TO 30 BELOW ZERO.
AVIATION
PANC...VFR CONDITIONS WILL PERSIST THROUGH THE PERIOD. THE LIGHT
WINDS ARE EXPECTED TO BECOME MORE NORTHERLY AND INCREASE UP TO 10
KT TONIGHT INTO THURSDAY.
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