916
FXAK68 PAFC 301438
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
538 AM AKST SUN NOV 30 2025
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3: TODAY
THROUGH TUESDAY)...
RELATIVELY WARM WEATHER WITH WINTRY-ISH PRECIPITATION CONTINUES
ACROSS MUCH OF SOUTHCENTRAL ALASKA. AS OF 5AM, RADAR SHOWS
PRECIPITATION BEGINNING TO PICK UP ONCE AGAIN ACROSS THE GULF OF
ALASKA AHEAD OF AN ADVANCING FRONT AND ASSOCIATED SHORTWAVE TROUGH
ALOFT. ADDITIONALLY, PRECIPITATION LINGERS ACROSS PORTIONS OF THE
MAT-SU VALLEY WHERE A MIX OF SLEET, SNOW, FREEZING RAIN, AND RAIN
ALL BEING OBSERVED THUS FAR OVERNIGHT.
GOES WATER VAPOR IMAGERY SHOWS A LARGE UPPER-LEVEL LOW ANCHORED
ACROSS THE NORTH PACIFIC, NEAR AND JUST SOUTH OF THE CENTRAL
ALEUTIANS / ANDREANOF ISLANDS. FARTHER EAST, WATER VAPOR IMAGERY
SHOWS A WELL-DEFINED BAROCLINIC LEAF ACROSS THE GULF OF ALASKA WHERE
A STRONG UPPER-LEVEL JET INTERACTS WITH THE FRONTAL BOUNDARY /
BAROCLINIC ZONE DRAPED ACROSS THE GULF. A SURFACE LOW WILL SOON
DEVELOP BENEATH THIS STRONG UPPER-LEVEL FORCING AND THIS DEEPEN
SLIGHTLY AS IT ADVANCES TOWARDS THE SOUTHERN COAST OF THE KENAI
PENINSULA.
MODEL SOUNDINGS AND OBSERVATIONAL TRENDS CONTINUE TO HIGHLIGHT THE
EXISTING WARM NOSE CENTERED AT APPROXIMATELY 925MB ON THE 12Z PAFC
SOUNDING. SOUTHEAST FLOW AHEAD OF THE ADVANCING LOW WILL HELP
REINFORCE THIS WARM LAYER TODAY ATOP THE EXISTING SHALLOW
SUBFREEZING LAYER NEAR THE SURFACE. AS PRECIPITATION SPREADS NORTH
TODAY, A TRANSITION ZONE OF MIXED PRECIPITATION IS EXPECTED AGAIN...
WITH PERIODS OF SNOW, SLEET, AND FREEZING RAIN ALL INCREASINGLY
LIKELY FROM ANCHORAGE NORTH INTO THE MAT-SU VALLEY. NEAR-SURFACE
TEMPERATURES HOVERING NEAR FREEZING WILL LIKELY MEAN THAT THE
TYPICALLY-COLDER POCKETS ACROSS ANCHORAGE AND THE BIG LAKE - HOUSTON
- WILLOW CORRIDOR ARE MOST LIKELY TO SEE SOME FREEZING RAIN / ICE
ACCRETION, WHILE WARMER AREAS IN THE WARM NOSE (E.G. HILLSIDE) AND
PORTIONS OF THE EVER-SO-WINDY MATANUSKA VALLEY MAY REMAIN ABOVE
FREEZING.
PRECIPITATION WILL BE AT ITS HEAVIEST ACROSS THE AREA THIS
AFTERNOON AND EVENING HOURS. WITH AN EXPECTED TEMPERATURE PROFILE
TO BE VERY CLOSE TO THE 0C ISOTHERM ABOVE THE SURFACE, HEAVY RATES
OF PRECIPITATION MAY RESULT IN JUST ENOUGH COOLER TO LEAD TO A
PERIOD OF SNOW, POTENTIALLY EVEN HEAVY/WET AT TIMES, WHILE TIMES
OF LIGHTER PRECIP MAY BE MORE RAIN OR DRIZZLE AND FREEZING
DRIZZLE. FLOW LATE OVERNIGHT ON THE HEELS OF THE PRECIPITATION AND
IN WAKE OF THE TROUGH PASSAGE WILL BECOME SOUTHERLY/UP-INLET...
WHICH MAY ALLOW FOR A TRANSITION BACK TO ALL RAIN, OR FREEZING
RAIN IN COLDER POCKETS.
WITH SOMEWHAT MORE CLARITY IS THE FORECAST FOR THE CENTRAL/EASTERN
CHUGACH INTO THE COPPER RIVER BASIN TODAY. THE SAME SYSTEM BRINGING
MIXED PRECIP WEST OF THE KENAI/CHUGACH MTNS WILL BRING SEVERAL
INCHES OF SNOW TO MUCH OF THE BASIN. 4 TO 8 INCHES OF SNOWFALL IS
LIKELY FOR MUCH OF THE RICHARDSON HIGHWAY, WITH HIGHER AMOUNTS IN
THOMPSON PASS AND OTHER HIGH-ELEVATION AREAS. THE BIGGEST CHALLENGE
WITH REGARDS TO THE COPPER RIVER BASIN FORECAST IS IN THE EDGERTON
HIGHWAY / MCCARTHY ROAD CORRIDOR WHERE SOME LOW-LEVEL WARM AIR
INTRUSION ABOVE NEAR-SURFACE COLD AIR MAY LEAD TO A PERIOD OF
FREEZING RAIN OR SLEET. CONFIDENCE IS ADMITTEDLY LOW IN THIS AREA
AND WE SELDOM RECEIVE GROUND-TRUTH REPORTS FROM THIS AREA, SO IF
YOU'RE IN CHITINA AND READING THIS... FEEL FREE TO GIVE US A
HOLLER AND TELL US WHAT'S HAPPENING THERE.
PRECIPITATION DIMINISHED OVERNIGHT TONIGHT. 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.
-BROWN/AS
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3)...
**KEY MESSAGE: A WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR THE
KUSKOKWIM DELTA AND KUSKOKWIM VALLEY FROM 1AM SUNDAY TO 5AM
MONDAY LESS THAN 1" OF SNOWFALL AND UP TO 0.2" OF ICE
ACCUMULATION.**
THE FIRST WAVE 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 RAIN AND SNOW MOVING
INTO THE Y-K DELTA. 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 850 MB,
VEERING WINDS ARE APPARENT IN THE SOUNDING PROFILE, WITH
NORTHEASTERLY WINDS AT THE SURFACE AND A SOUTHEASTERLY WIND
BRINGING WARMER AIR ALOFT. A WARM NOSE BELOW 2000 FEET APPEARS IN
THE SOUNDING ABOVE A COLD AIRMASS AT THE SURFACE, CIRCUMSTANCES
FAVORING SLEET AND FREEZING RAIN. AREAS UNDER THE WINTER WEATHER
ADVISORY WILL SEE A WINTRY MIX OF PRECIPITATION CONTINUE THROUGH
THE DAY.
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, WARMER AIR WILL BE USHERED IN THAN
IN THE FIRST WAVE, SO PLACES ALONG BRISTOL BAY COULD VERY WELL
WARM INTO THE 40S, WITH JUST BELOW FREEZING TEMPERATURES HOLDING
ON ACROSS THE Y-K DELTA AND IN VALLEY LOCATIONS. ONE NOTE OF
CAUTION IS THAT DENSER COLD AIR CAN BE STUBBORN TO MIX OUT FROM
VALLEYS AS IT TENDS TO POOL IN LOW TERRAIN, 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 0.3" IS EXPECTED FOR THE Y-K DELTA COAST, AND UPWARDS
OF 0.20-0.30" INLAND ACROSS THE VALLEYS IS EXPECTED INTO THE
SLEETMUTE AREA.
-AM/ER
.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 WILL GENERALLY PREVAIL THROUGH THE MORNING
BEFORE DETERIORATING LATER TODAY. LLWS WILL BE A CONCERN THROUGH
MUCH OF THE DAY AS STRONG SOUTHEAST WINDS IN THE 2-3KFT LAYER SIT
ABOVE NORTHEAST WINDS AT THE SURFACE. PRECIPITATION IS EXPECTED TO
OVERSPREAD THE ANCHORAGE AREA ONCE AGAIN THIS AFTERNOON AND
CONTINUE INTO THE EVENING BEFORE DIMINISHING OVERNIGHT. WITH
TEMPERATURES IN THE LOWER ATMOSPHERE EXPECTED TO HOVER RIGHT NEAR
FREEZING THROUGH THE DURATION OF THIS PRECIP, ALL PRECIPITATION
TYPES ARE ON THE TABLE. FZRA TO SN IS MOST LIKELY IN THE
AFTERNOON, WITH SN BECOMING MORE LIKELY IF PRECIPITATION INTENSITY
INCREASES. THEN UP-INLET FLOW AND WARMER NEAR-SFC TEMPS LATE
OVERNIGHT MAY TRANSITION ANY LINGERING PRECIP BACK TO RAIN. CIG
AND VIS DEGRADATION IS EXPECTED LATER TODAY AS THIS PRECIP MOVES
IN, WITH IFR POSSIBLE IN THE EVENING.
-BROWN
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