347
FXAK68 PAFC 010159
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
459 PM AKST SUN NOV 30 2025
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3:
TONIGHT THROUGH WEDNESDAY)...
AN UPPER LEVEL TROUGH/LOW IS CONTINUING TO PROGRESS NORTH FROM THE
GULF INTO THE PRINCE WILLIAM SOUND THIS AFTERNOON, WITH COLDER
CLOUD TOPS ON GOES WEST SATELLITE IMAGERY NOW SHIFTING NORTHWEST
AND INLAND ACROSS SOUTHCENTRAL. A SURFACE LOW IN THE EASTERN GULF
IS MOVING UP TOWARDS THE KENAI PENINSULA SOUTH OF SEWARD. WITH A
GALE FORCE FRONT EXTENDING NORTHEAST NOW JUST WORKING ONSHORE
ALONG THE GULF COAST. A MIX OF SNOW, SLEET AND FREEZING RAIN THAT
CAME IN TO PARTS OF THE MAT-SU VALLEYS AND ANCHORAGE EARLIER
TODAY HAS MOSTLY TAPERED OFF FOR THE TIME BEING. THIS IS MAINLY
DUE TO THE POSITION OF THE INCOMING TROUGH AND SURFACE LOW,
CURRENTLY CAUSING A BIT OF EASTERLY FLOW AND DOWNSLOPE DRYING OFF
OF THE CHUGACH/KENAI MOUNTAINS. THE LATEST ANCHORAGE OBSERVED
SOUNDING CONTINUES TO SHOW A WARM LAYER ABOVE FREEZING FROM ABOUT
1000 TO 3000 FT ABOVE GROUND LEVEL, AND THIS WARM AIR ALOFT ATOP
SUB-FREEZING TEMPERATURES NEAR THE GROUND IS RESPONSIBLE FOR THE
MULTIPLE ROUNDS OF WINTRY MIX WE'VE SEEN ACROSS PARTS OF
ANCHORAGE, THE MAT-SU AND KENAI PENINSULA OVER THE PAST 24 HOURS.
THIS WARM NOSE IS STARTING TO COOL COMPARED TO THIS MORNING,
HOWEVER, AND THIS COOLING TREND IS LIKELY TO CONTINUE THIS
EVENING.
IT REMAINS LIKELY FOR A TRANSITION FROM A WINTRY MIX TO MAINLY
SNOW TO OCCUR SOMETIME THIS EVENING AS TEMPERATURES ALOFT COOL
WHILE THE SURFACE LOW SHIFTS INTO PRINCE WILLIAM SOUND, ALLOWING
EASTERLY FLOW AND DOWNSLOPE DRYING TO ABRUPTLY ABATE. IT'S STILL
NOT OUT OF THE QUESTION FOR SEVERAL INCHES OF SNOWFALL (AND LESS
FREEZING RAIN) TO MOVE INTO PARTS OF ANCHORAGE AND THE MAT VALLEY
OVERNIGHT IF THE TRANSITION OVER TO SNOW CAN HAPPEN ON THE EARLIER
SIDE DURING THE OVERNIGHT TONIGHT.
SHIFTING ATTENTION OVER TO THE EAST, A SOUTHERLY PUSH OF WARM AIR
ALOFT HAS MADE IT INTO PORTIONS OF THE RICHARDSON HIGHWAY
CORRIDOR, SIMILARLY RESULTING IN A MIX OF SNOW, SLEET AND
FREEZING RAIN WHERE LOW LEVEL TEMPERATURES ARE STILL BELOW
FREEZING. THIS HAS MOSTLY BEEN CONCENTRATED ALONG A STRETCH OF THE
RICHARDSON BETWEEN TONSINA AND THOMPSON PASS, WHERE A WINTER
WEATHER ADVISORY HAS BEEN ISSUED THROUGH MIDDAY TOMORROW AS
PERIODS OF FREEZING RAIN AND SNOW ARE SET TO CONTINUE INTO
TOMORROW MORNING. MOST OF THE REST OF THE COPPER BASIN IS
CONTINUING TO STAY COLD ENOUGH FOR SNOW, BUT THERE WILL BE A
CHANCE FOR WARMER AIR TO CONTINUE TO SPREAD NORTH OVERNIGHT
TONIGHT, POSSIBLY RESULTING IN MORE MIXING WITH FREEZING RAIN AND
SLEET AS FAR NORTH AND EAST AS GLENNALLEN AND MCCARTHY FROM THIS
EVENING INTO MONDAY.
LOOKING A BIT FARTHER OUT TOWARDS MIDWEEK, THE WARM PATTERN LOOKS
TO PERSIST IN THE NEAR TERM. IT LOOKS LIKE A BIT MORE OF A BREAK
IN PRECIPITATION IS NOW POSSIBLE FROM MONDAY AFTERNOON INTO
TUESDAY MORNING AS THE UPPER TROUGH CURVES EAST TOWARDS THE YUKON
AND AS AN UPPER LEVEL RIDGE MOVES IN FROM SOUTHWEST. AREAS OF SNOW
WILL LINGER FOR THE LONGEST ACROSS THE COPPER BASIN, ESPECIALLY
FROM GLENNALLEN NORTH TO PAXON AND MENTASTA LAKE. A STRONG BERING
LOW WILL SEND ANOTHER FRONT ACROSS THE REGION FROM THE SOUTHWEST
BY EARLY TUESDAY, SENDING ANOTHER BATCH OF WARM SOUTHERLY FLOW AND
PRECIPITATION BACK INTO SOUTHCENTRAL. WITH THE EXCEPTION OF THE
COPPER BASIN AND NORTHERN SUSITNA VALLEY, IT LOOKS LIKELY
TEMPERATURES WILL BE WARM ENOUGH THIS TIME FOR MOSTLY RAIN TO MOVE
IN WITH THIS FRONT AT LOWER ELEVATIONS. STILL, SOME MIXING WITH
FREEZING RAIN CANNOT BE ENTIRELY RULED OUT FOR SPOTS THAT HOLD ON
TO COLDER TEMPERATURES, SUCH AS THE SOUTHERN SUSITNA VALLEY AND
WESTERN MATANUSKA VALLEY. RAIN AND HIGHER ELEVATION SNOW WILL COME
TO AN END FOR THE MOST PART BY WEDNESDAY AS THE SURFACE FRONT
WEAKENS AND HANGS UP ALONG THE GULF COAST AND AS TEMPERATURES TURN
THE CORNER TOWARDS WHAT COULD BE A RATHER DRAMATIC COOLING TREND
LATER THIS WEEK.
-AS
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3)...
...ICE STORM WARNING NOW IN EFFECT FROM 3AM TUESDAY TO 9AM
WEDNESDAY FOR SIGNIFICANT ICING FOR THE KUSKOKWIM DELTA, KUSKOKWIM
VALLEY, INCLUDING BETHEL, ANIAK, AND CROOKED CREEK...
...ICE ACCUMULATIONS OF ONE HALF TO THREE QUARTERS OF AN INCH
EXPECTED ALONG THE COAST BY WEDNESDAY MORNING. ICE ACCUMULATIONS
OF ONE QUARTER OF AN INCH EXPECTED ACROSS THE KUSKOKWIM VALLEY.
TOTAL SNOWFALL ACCUMULATIONS UP TO 4 INCHES. WINDS GUSTING AS HIGH
AS 35 MPH ALONG THE COAST AND 15 MPH FOR INLAND LOCATIONS...
OUR WELL ADVERTISED TWO FOLD WINTER STORM IS WELL UNDERWAY ACROSS
THE YUKON-KUSKOKWIM (YK) DELTA AND KUSKOKWIM VALLEY. CURRENT
SURFACE TEMPERATURES ARE IN THE LOW 20S FOR BETHEL AND MID 20S FOR
KIPNUK, OWING TO A STOUT NORTHEAST WIND RESUPPLYING COLD AIR TO
THE REGION. THESE TEMPERATURES ARE ABOUT 5 DEGREES COLDER THAN
WHAT THE MODELS THINK THEY SHOULD BE. FARTHER SOUTH FROM THE
KUSKOKWIM MOUNTAINS SOUTHWARD, THERE HAS BEEN A WIND SHIFT TO
EASTERLY TO SOUTHEASTERLY, AND TEMPERATURES HAVE WARMED INTO THE
MID 30S. RADAR RETURNS AND SURFACE OBSERVATIONS SHOW SNOW SHOWERS
HAVE TRANSITIONED TO PERIODS OF LIGHT FREEZING RAIN FOR BETHEL,
WITH THE 12Z BETHEL SOUNDING SHOWING A MODEST WARM NOSE WITH THE
WET BULB BELOW FREEZING. THE FORECAST SEEMS TO BE MOSTLY ON TRACK
AS PRECIPITATION STREAMS NORTHWARD ACROSS THE YK DELTA AND VALLEY,
THOUGH SHOULD REMAIN LIGHT DUE TO SOME DEGREE OF DOWNSLOPING FROM
THE KUSKOKWIM MOUNTAINS. THE GFS HAS BEEN THE OUTLIER IN PREVIOUS
RUNS AT BEING MUCH A COLDER SOLUTION OVERALL, BUT LATEST RUNS
HAVE BEEN MORE IN LINE WITH THE NAM, WHICH HAS BEEN THE FAVORED
MODEL WITH THIS SYSTEM. THEREFORE, FORECASTER CONFIDENCE HAS
INCREASED SINCE THIS TIME YESTERDAY.
ALOFT, WEAK DIFFLUENCE STILL REMAINS ACROSS SOUTHWEST ALASKA
DOWNSTREAM OF A TROUGH THAT HAS DUG ITS WAY OVER THE NORTH
PACIFIC, WELL SOUTH OF THE ALEUTIANS. A COUPLE OF WEAK VORTICITY
LOBES ORIGINATING FROM THE TROUGH SHOULD MOVE ACROSS THE AREA THIS
AFTERNOON/EVENING, GIVING A LITTLE MORE LIFT/FORCING TO WRING OUT
MORE LIGHT SNOW/ OR LIGHT FREEZING RAIN. IN ADVANCE OF A FAST
MOVING NORTH PACIFIC LOW, THE OVERALL 500 MB MEAN FLOW BECOMES
INCREASINGLY DIFLUENT ONCE AGAIN ACROSS SOUTHWEST ALASKA, AND ITS
FRONT WILL BE ACCOMPANIED BY A PLETHORA OF MOISTURE AS THE
LOW/FRONT NEARS THE ALEUTIAN CHAIN. THE ONSET OF HEAVIER
PRECIPITATION ACROSS THE ICE STORM WARNED AREAS LIKELY BEGINS
EARLY TUESDAY MORNING. BY THIS TIME, THE HIGHER RESOLUTION
GUIDANCE AND THE GLOBAL MODELS INDICATE THAT 925 MB TEMPERATURES
WILL BE ABOVE FREEZING AS WINDS ALOFT SHIFT FROM SOUTHEASTERLY TO
EASTERLY. WITH COLDER NORTHEASTERLY WINDS AT THE SURFACE, KIPNUK
EASTWARD TO BETHEL, AND THEN ONWARD TO ANIAK AND CROOKED CREEK,
WILL SEE A HIGH IMPACT ICE STORM. EVERY BIT OF GUIDANCE SAYS THAT
THIS SECOND WAVE WILL BE SIGNIFICANTLY STRONGER AND MORE MOISTURE
RICH THAN THE FIRST, SO QPF AMOUNTS WILL BE SUBSTANTIALLY HIGHER
AS WELL. THIS WILL BE A LONG DURATION ICING EVENT, AND WILL ONLY
WIND DOWN AS THE DIFFLUENCE ALOFT RELAXES AND THE FRONT CLEARS THE
AREA WEDNESDAY MORNING. DEPENDING ON EXACT TIMING, FREEZING
DRIZZLE COULD LINGER PAST WEDNESDAY MORNING, THOUGH THE VAST
MAJORITY OF PRECIPITATION/ICING WILL FALL AND OCCUR TUESDAY
MORNING TO WEDNESDAY MORNING.
-AM
.LONG TERM FORECAST (DAYS 4 THROUGH 7 - THURSDAY THROUGH
SUNDAY)...
THURSDAY BEGINS WITH THE LOW OVER THE CENTRAL ALEUTIANS
WEAKENING. THIS LEADS TO LOWER PRECIPITATION CHANCES AND WINDS
SPEEDS FOR THE ALEUTIANS AND THE SOUTHWEST MAINLAND. SOUTHCENTRAL
ALASKA WILL ALSO HAVE A DRYING TREND AS HIGHER PRESSURE MOVES INTO
THE REGION. ALL OF THIS LESS ACTIVE WEATHER WILL BE ACCOMPANIED
BY A LARGE COOLDOWN DUE TO COLD AIR ADVECTION FROM THE NORTH.
THINGS GET MORE UNCERTAIN MOVING INTO FRIDAY AS THE COOLDOWN
CONTINUES. SOME GUIDANCE HAS THE COLDER AIR KEEPING MORE TO THE
EAST, WITH WESTERN ALASKA SEEING LESS COLD TEMPERATURES WHEREAS
OTHER GUIDANCE HAS THE ARCTIC AIR TAKING A MORE WESTERN TRACK AND
ENCOMPASSING ALMOST THE WHOLE STATE. THIS ALSO HAS IMPLICATIONS
FOR STORM TRACKS AS WELL. IF THE COLDER AND MORE STABLE AIR TAKES
THE WESTERN TRACK, LESS ACTIVE WEATHER CAN BE EXPECTED FOR WESTERN
ALASKA, BUT IF THE EASTERN TRACK WINS OUT, THERE IS A POTENTIAL
FOR LOWS TO MAKE IT INTO THE BERING AND CAUSE SNOWFALL AND WINDS
IN THE SOUTHWEST MAINLAND. THE STORY IS THE SAME FOR THE WEEKEND
REGARDING UNCERTAINTY. REGARDLESS OF WHAT OCCURS, WHAT IS KNOWN
IS THAT SOUTHCENTRAL AND SOUTHWEST ALASKA WILL EXPERIENCE MUCH
COLDER TEMPERATURES BY THE END OF THE WEEK INTO THE WEEKEND AND
THAT LESS ACTIVE WEATHER WILL ACCOMPANY THIS COOLING TREND.
-JAR
AVIATION
PANC...
TEMPERATURES IN THE LOWER ATMOSPHERE ARE EXPECTED TO HOVER RIGHT
NEAR FREEZING THROUGH THE NIGHT AND INTO MONDAY. WITH
PRECIPITATION MOVING BACK INTO THE AREA THIS AFTERNOON THROUGH
OVERNIGHT HOURS, ALL PRECIPITATION TYPES ARE ON THE TABLE. RAIN IS
THE MOST LIKELY TYPE FOR THIS AFTERNOON, WITH SN BECOMING MORE
LIKELY THIS EVENING. THE LOW CAUSING THIS PRECIPITATION IS EDGING
A LITTLE FARTHER TO THE EAST WHICH WILL LESSEN THE CHANCE FOR
FREEZING RAIN AND KEEP IT MORE OF A QUESTION OF RAIN OR SNOW.
EITHER WAY, MVFR TO IFR CONDITIONS ARE EXPECTED THIS EVENING UNTIL
MONDAY MORNING WHERE AT LEAST THE VISIBILITIES ARE EXPECTED TO
RETURN TO VFR, THOUGH MVFR CEILINGS MAY PERSIST THROUGH MOST OF
MONDAY.
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