586
FXAK68 PAFC 300213
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
513 PM AKST SAT NOV 29 2025
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3:
TONIGHT THROUGH TUESDAY)...
THE MUCH-ADVERTISED ACTIVE PATTERN IS TAKING SHAPE THIS EVENING
AS A STRONG WARM FRONT ASSOCIATED WITH A VERY LARGE NORTH PACIFIC
LOW BEGINS TO MOVE UP INTO THE GULF. A PLUME OF MOISTURE AND LIFT
HAS ALREADY OVERSPREAD MUCH OF SOUTHCENTRAL OUT AHEAD OF THIS
FRONT, WITH STEADY PRECIPITATION ALONG THE COAST NOW STARTING TO
FILL IN QUICKLY ACROSS THE WESTERN KENAI PENINSULA AND COOK INLET
REGION AS RADAR RETURNS CLOSE IN ON THE RADAR SITE, INDICATING A
SHIFT FROM MOSTLY VIRGA TO PRECIPITATION REACHING THE GROUND.
TEMPERATURES ALOFT HAVE STAYED SLIGHTLY COOLER THAN MODEL
PROJECTIONS HAVE INDICATED FOR THIS AFTERNOON, AS NOTED IN THE 00Z
ANCHORAGE SOUNDING, CAPTURING ONLY A SMALL LAYER ABOVE FREEZING
BETWEEN ABOUT 950 AND 900 MB. THIS HAS HELPED KEEP PRECIPITATION
TYPE MOSTLY SNOW WITH THE INITIAL ARRIVAL OF PRECIPITATION MAKING
IT TO GROUND LEVEL. MEANWHILE, MUCH OF THE INTERIOR KENAI
PENINSULA HAS SEEN A MIX OF RAIN, SNOW AND FREEZING RAIN ALREADY
TODAY, WHERE TEMPERATURES ALOFT ARE WARMER AND WHERE SURFACE
TEMPERATURES HAVE BEEN SLOW TO RISE ABOVE FREEZING. THIS HAS
CONTRIBUTED TO RATHER TREACHEROUS CONDITIONS ALONG PARTS OF THE
STERLING AND SEWARD HIGHWAY CORRIDOR FROM TURNAGAIN PASS SOUTH TO
COOPER LANDING AND MOOSE PASS, WHERE THE WINTER WEATHER ADVISORY
HAS BEEN EXPANDED TO COVER THE ONGOING RAIN AND FREEZING RAIN
EVENT THROUGH THIS EVENING.
MUCH OF THE FORECAST FROM TONIGHT ONWARDS CONTINUES TO BE MARRED
WITH QUITE A LOT OF UNCERTAINTY REGARDING KEY DETAILS IN THE TRACK
AND PROGRESSION OF A COUPLE IMPORTANT FEATURES, AS WELL AS THE
BEHAVIOR OF LOW-LEVEL TEMPERATURES OVER THE COURSE OF THE NEXT
COUPLE DAYS. EVEN IN THE VERY NEAR TERM FOR THE OVERNIGHT TONIGHT,
THERE IS A LARGE DEGREE OF SPREAD IN TERMS OF HOW MUCH
PRECIPITATION IS ABLE TO SPILL OVER THE MOUNTAINS INTO THE MAT-SU,
ANCHORAGE AND KENAI PENINSULA. THIS SEEMS TO STEM PRIMARILY FROM
DIFFERENCES IN THE ORIENTATION OF MID-LEVEL FLOW, WITH SOME
SOLUTIONS SHOWING WINDS ALOFT STAY A BIT MORE SOUTHERLY WITH LESS
DOWNSLOPE DRYING OFF OF THE KENAI AND CHUGACH MOUNTAINS. OTHER
MODEL SOLUTIONS ARE KEEPING MUCH OF THE CORRIDOR FROM KENAI TO
WASILLA/PALMER MOSTLY DRY THROUGH SUNDAY MORNING, WITH MORE TRUE
DOWNSLOPE/SOUTHEAST FLOW DOMINATING. THERE IS ALSO THE QUESTION OF
WHEN A TRANSITION OVER FROM SNOW/FLURRIES TO FREEZING RAIN MIGHT
OCCUR, WHICH WILL ENTIRELY DEPEND ON HOW MUCH WARM ADVECTION CAN
CONTINUE TO PUSH TEMPERATURES IN THE EXISTING WARM NOSE ALOFT
HIGHER THROUGH TONIGHT INTO TOMORROW. BOTTOM LINE, EXPECT
CONSIDERABLE VARIATION IN CONDITIONS ACROSS THE REGION COVERED
WITHIN THE WINTER WEATHER ADVISORY AREA. CONDITIONS COULD VARY
FROM MOSTLY RAIN WITH TEMPERATURES HOVERING AT OR JUST ABOVE
FREEZING, TO PERIODS OF FREEZING RAIN OR LIGHT SNOW THROUGH SUNDAY
MORNING.
FOR SUNDAY MORNING ONWARDS, DISCREPANCIES IN MODEL DATA CONTINUE
TO HAMPER FORECAST CONFIDENCE. STILL, THE LARGE SCALE PATTERN
EXPECTATIONS STILL ARE ABOUT THE SAME OVERALL COMPARED TO WHAT WE
WERE THINKING YESTERDAY TO START OFF THE WEEK. THE STRONG FRONT
WILL PUSH A STORM FORCE BARRIER JET INTO THE GULF COAST AS IT
CONTINUES TO LIFT NORTH ON SUNDAY, THEN RAPIDLY WEAKEN AS IT HEADS
INLAND SUNDAY EVENING. MEANWHILE, A COMPACT LOW IS EXPECTED TO
SPIN UP AHEAD OF A SHORTWAVE TROUGH LIFTING NEARLY DUE NORTH FROM
THE WESTERN GULF AS THE FRONT IS MOVING ONSHORE. BY SUNDAY NIGHT,
THE UPPER LEVEL WAVE IS EXPECTED TO OUTRUN THE SURFACE LOW
NEAR/OVER THE SOUTHERN KENAI PENINSULA AND CONTINUE TO LIFT NORTH
INTO THE WESTERN HALF OF SOUTHCENTRAL.
WHAT ALL THIS WILL MEAN, IN SHORT, IS QUITE A LOT OF CONTINUED
PRECIPITATION FOR A GOOD PORTION OF BOTH THE COASTLINE AND THE
INTERIOR VALLEYS FROM SUNDAY INTO SUNDAY NIGHT. PRECIPITATION TYPE
DURING THIS WINDOW IS WHERE FORECAST CONFIDENCE IS THE LOWEST.
MODELS DIVERGE QUITE A BIT IN TERMS OF HOW MUCH THE CONTINUED
ONSLAUGHT OF SOUTH TO SOUTHEASTERLY FLOW WILL HELP PUSH LOW-LEVEL
TEMPERATURES ABOVE FREEZING, ESPECIALLY NEAR ANCHORAGE, THE MAT-
SU, AND COPPER BASIN. AS THE UPPER LEVEL LOW LIFTS NORTH, HEAVIER
PRECIPITATION WILL LIKELY FILL IN BETWEEN THE WESTERN KENAI
PENINSULA AND MAT-SU BY SUNDAY AFTERNOON. CURRENTLY, THE FORECAST
FAVORS A SCENARIO WHERE MOST OF THIS CORRIDOR ENDS UP TURNING OVER
TO COLD RAIN THROUGH MONDAY MORNING. HOWEVER, A FEW INCHES OF VERY
SLUSHY, WET SNOW IS NOT OUT OF THE QUESTION FOR PARTS OF
ANCHORAGE AND THE MAT VALLEY BETWEEN SUNDAY AND MONDAY IF THE
COLDER MODEL SOLUTIONS FOR LOW-LEVEL TEMPERATURES COME TO
FRUITION. PRECIPITATION TYPE TROUBLES COULD ALSO AFFECT PARTS OF
THE COPPER BASIN ON SUNDAY, WHERE A MIX OF SNOW, SLEET AND
FREEZING RAIN COULD MATERIALIZE IF WARMER AIR STREAMING IN FROM
THE SOUTH IS NOT ABLE TO SCOUR OUT COLD AIR IN PLACE QUICKLY
ENOUGH.
FROM MONDAY TO TUESDAY, THE UPPER TROUGH WILL SHIFT EAST TOWARDS
THE YUKON AS ANOTHER VERY TRANSIENT UPPER RIDGE MOVES ACROSS
SOUTHCENTRAL IN BETWEEN STRONGER STORM SYSTEMS. THE NEXT FRONTAL
SYSTEM WILL QUICKLY MOVE IN FROM THE WEST DURING THE DAY ON
TUESDAY AS ANOTHER STRONG LOW MOVES UP INTO THE BERING SEA OUT
WEST. AT THIS TIME, IT APPEARS LIKELY MOST LOCATIONS NEAR SEA
LEVEL WILL REMAIN WARM ENOUGH FOR MOSTLY RAIN TO FALL WITH THE
ARRIVAL OF THIS NEXT FRONT, WITH SNOW CONFINED TO MAINLY HIGHER
TERRAIN AS VERY WARM AIR CONTINUES TO SPREAD NORTH. STAY TUNED FOR
UPDATES AS WE CONTINUE TO FOLLOW THIS WARM AND ACTIVE PATTERN INTO
EARLY NEXT WEEK.
-AS
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3)...
**KEY MESSAGE: THE WINTER STORM WATCH HAS BEEN UPGRADED TO A
WINTER WEATHER ADVISORY FOR THE KUSKOKWIM DELTA AND KUSKOKWIM
VALLEY FROM 1 AM SUNDAY TO 5 AM MONDAY FOR UP TO 2" OF SNOWFALL
AND 0.2" OF ICE ACCUMULATION.**
SATELLITE IMAGERY IS RATHER MESSY THIS AFTERNOON AS THE FIRST
PHASE OF OUR ADVERTISED WINTER STORM IS UNDERWAY ACROSS SOUTHWEST
ALASKA. A COMPLEX LOW PRESSURE SYSTEM STILL SPINS SOUTH OF THE
ALEUTIAN CHAIN AS A FRONT CONTINUES TO DRIVE PRECIPITATION AND
WARM AIR ADVECTION NORTHWARD ACROSS THE REGION. SURFACE
OBSERVATIONS AND RADAR IMAGERY ALREADY SHOWS THE FIRST WAVE OF
RAIN/SNOW MOVING IN A COUPLE OF HOURS AHEAD OF SCHEDULE FROM
BRISTOL BAY ACROSS THE DILLINGHAM AREA, WITH RAIN FALLING FOR KING
SALMON. ALOFT, THE FLOW ACROSS THE ALASKA PENINSULA AND SOUTHWEST
ALASKA IS DIFLUENT DOWNSTREAM OF A TROUGH THAT HAS DUG WELL
SOUTHWARD OVER THE NORTH PACIFIC, WHICH IS AIDING THE FRONT IN
PROVIDING SYNOPTIC FORCING. FROM THE SURFACE TO 925 MB, AND THEN
TO 850 MB, GUIDANCE CONTINUES TO INDICATE A STRONG VEERING WIND
PROFILE, WITH EASTERLY WINDS BRINGING IN WARMER AIR AT THE SURFACE
AND A SOUTHEASTERLY WIND DOING THE SAME ALOFT, PARTLY DUE TO A
DOWNSLOPING COMPONENT IN LEE OF THE WESTERN ALASKA RANGE AND
NORTHERN ALEUTIAN RANGE. THE WARM NOSE EFFECT AND A JUST ABOVE
FREEZING AIRMASS AT THE SURFACE FOR THE BRISTOL BAY AREA HAS
ARRIVED, WHICH HAS TRANSITIONED AREAS SUCH AS DILLINGHAM FROM SNOW
TO RAIN. AREAS UNDER THE WINTER WEATHER ADVISORY WILL SEE
PRECIPITATION MOVE IN THIS EVENING AND OVERNIGHT. THIS IS WHERE
THE COLD AIR AT THE SURFACE WILL BE MOST ESTABLISHED WITH A
NORTHERLY REINFORCING WIND, SO THE IDEA IS THE LEADING EDGE OF
PRECIPITATION WILL BE SNOW, AND AS THE WARM NOSE MOVES IN, A
TRANSITION TO FREEZING RAIN WILL OCCUR. AS STATED IN THE ADVISORY,
UP TO 2 INCHES OF SNOW AND 0.2" OF ICE ACCUMULATION IS EXPECTED
FOR THESE AREAS THROUGH MONDAY MORNING.
THERE COULD BE SOMEWHAT OF A LULL IN ACTIVITY MONDAY MORNING
THROUGH MONDAY AFTERNOON FOR THE KUSKOKWIM VALLEY, THOUGH THE YK
DELTA COAST COULD STILL CONTINUE TO LIGHTLY PRECIPITATE. AREAS OF
FREEZING DRIZZLE COULD LINGER THROUGH THIS TIME PERIOD AS THE
UPPER FLOW AGAIN BECOMES DIFLUENT IN NATURE AS ANOTHER NORTH
PACIFIC LOW RACES NORTHWARD TOWARDS THE EASTERN HALF OF THE
ALEUTIAN CHAIN WITH A SLUG OF MOISTURE AHEAD OF ITS FRONT. LATE
MONDAY AFTERNOON IS WHERE THE SECOND PHASE OF THE EVENT STARTS,
AND THIS ONE WILL BE FAR MORE IMPACTFUL. THERE WILL BE
SIGNIFICANTLY MORE QPF WITH THIS SYSTEM, AND WIND PROFILES AT THE
SURFACE AND ALOFT WILL CLOSELY RESEMBLE THE FIRST WAVE. WITH A
STRONGER PUSH WITH THIS FRONT, A STRONGER SURGE OF WARMER AIR WILL
BE USHERED IN COMPARED TO THE FIRST WAVE, SO PLACES ALONG BRISTOL
BAY COULD VERY WELL WARM INTO THE 40S, WITH JUST BELOW FREEZING
TEMPERATURES HOLDING ON ACROSS THE YK DELTA AND VALLEY LOCATIONS.
ONE NOTE OF CAUTION IS THAT COLD AIR CAN BE STUBBORN TO ERODE FROM
VALLEYS AS IT IS DENSE AND WANTS TO HUG THE SURFACE, SO FREEZING
RAIN COULD BE PROLONGED FOR THESE AREAS BEFORE A CHANGEOVER TO
RAIN. WITH COLD AIR NOT WELL ESTABLISHED, THE LATENT HEAT RELEASE
FROM THE FREEZING RAIN WILL HELP TO FURTHER WARM SURFACE
TEMPERATURES ELSEWHERE. BY TUESDAY AFTERNOON, SIGNIFICANT ICE
ACCUMULATION OF UPWARDS OF 0.5" IS EXPECTED FOR THE YK DELTA
COAST, AND UPWARDS OF 0.25-0.35" INLAND ACROSS THE VALLEYS IS
EXPECTED INTO THE SLEETMUTE AREA. PLEASE STAY TUNED TO THE
FORECAST FOR FURTHER UPDATES AS THE EVENT CONTINUES TO UNFOLD.
-AM
.LONG TERM FORECAST (DAYS 4 THROUGH 7 - WEDNESDAY THROUGH
SATURDAY)...
THE LONG TERM FORECAST STARTS WITH A LARGE LOW IN THE BERING OVER
THE CENTRAL ALEUTIANS. THIS LOW BRINGS A LARGE SWATH OF
PRECIPITATION TO ALMOST ALL OF THE ALEUTIANS, THE PRIBILOF
ISLANDS, AND MAINLAND SOUTHWEST ALASKA. BY THIS POINT IN TIME,
COOLER AIR WILL FILTER INTO THE SOUTHWEST MAINLAND, ALLOWING FOR
FREEZING RAIN CHANCES TO DIMINISH AND FOR SNOWFALL TO BE THE
PREDOMINANT PRECIPITATION TYPE. HOWEVER, BRISTOL BAY WILL LIKELY
REMAIN AS RAIN OR RAIN/SNOW FOR WEDNESDAY. GALE FORCE WINDS FROM
THE CENTRAL ALEUTIANS TO KUSKOKWIM COAST ARE POSSIBLE.
SOUTHCENTRAL ALASKA WILL SEE LINGERING PRECIPITATION AS THE
REMNANTS OF A FRONT LINGER OVER THE AREA. THURSDAY HAS A HIGHER
AMOUNT OF UNCERTAINTY. IN SOUTHWEST ALASKA, IT IS LIKELY THAT THE
MAINLAND WILL SEE COLDER AIR MOVE IN AS WINDS BECOME NORTHERLY.
THIS WILL LIKELY BRING IN DRIER AIR, WHICH WOULD DECREASE CHANCES
FOR PRECIPITATION. THE BERING COULD SEE THE LOW WEAKEN AS IT
REMAINS MOSTLY STATIONARY WITH LIGHT PRECIPITATION CONTINUING.
SOME GUIDANCE HAS THE LOW DISSIPATING EARLIER, WHICH WOULD MEAN
LOWER PRECIPITATION CHANCES. NORTHWEST WINDS WILL ALLOW FOR
ELEVATED WIND SPEEDS IN THE KUSKOKWIM DELTA (15 TO 20 MPH).
SOUTHCENTRAL MAY HAVE A BREAK IN ACTIVE WEATHER, WITH DRIER AND
COOLER AIR MOVING IN.
FRIDAY AND SATURDAY ARE HIGHLY UNCERTAIN, BUT WILL LIKELY SEE THE
CONTINUATION OF DECREASING TEMPERATURES DUE TO AN ARCTIC AIR MASS
DROPPING INTO ALASKA. AS FOR OTHER FEATURES, SOME KIND OF A LOW
MAY MOVE INTO THE GULF OF ALASKA, ALLOWING FOR HIGHER
PRECIPITATION CHANCES AND WIND SPEEDS, THOUGH IT IS UNCERTAIN
EXACTLY WHERE THIS WILL SET UP. SOUTHWEST ALASKA MAY SEE A BREAK
IN ACTIVE WEATHER AS A COL SETS UP, ALLOWING FOR LIGHTER WINDS AND
LOWER CHANCES FOR PRECIPITATION.
-JAR
AVIATION
PANC...VFR CONDITIONS WITH CEILINGS ABOVE 5000 FT AND LIGHT
NORTHERLY WINDS WILL PERSIST THROUGH MUCH OF THE TAF PERIOD. A
WINTRY MIX OF PRECIPITATION WILL QUICKLY MOVE OVER THE TERMINAL
THIS AFTERNOON. A MIX OF SNOW, SLEET, AND FREEZING RAIN IS
POSSIBLE INITIALLY, WITH CEILINGS AND VISIBILITY DROPPING TO MVFR,
BEFORE THE PRECIPITATION CHANGES OVER TO FREEZING RAIN.
TEMPERATURES GRADUALLY INCREASE TONIGHT, SO LINGERING
PRECIPITATION EVENTUALLY TURNS OVER TO ALL RAIN. A LIGHT GLAZE TO
A TENTH OF AN INCH OF ICE IS POSSIBLE. LLWS IS ALSO LIKELY TONIGHT
THROUGH MONDAY MORNING AS SOUTHEASTERLY WIND ALOFT INCREASE AHEAD
OF A FRONT LIFTING NORTH TOWARD PRINCE WILLIAM SOUND.
CEILINGS AND VISIBILITY IMPROVE BACK TO VFR AFTER MIDNIGHT WITH
DIMINISHING PRECIPITATION. ANOTHER ROUND OF LIGHT PRECIPITATION IS
POSSIBLE ON SUNDAY, WITH MORE UNCERTAIN TIMING. THIS IS EXPECTED
TO FALL AS A MIX OF RAIN AND SNOW WITH MINIMAL CHANCES FOR
FREEZING RAIN. CEILINGS AND VISIBILITY POTENTIALLY DROP BACK TO
MVFR DURING HEAVIER PRECIPITATION, ESPECIALLY IF SNOW.
-TM/QUESADA
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