572
FXAK68 PAFC 231357
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
457 AM AKST TUE DEC 23 2025
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3: TODAY
THROUGH THURSDAY)...
COLD WEATHER ADVISORIES REMAIN IN EFFECT FOR THE COPPER BASIN AND
THOMPSON PASS WHERE WIND CHILLS IN THE RANGE OF -45 TO -60 WILL
CONTINUE TO BE POSSIBLE. DRAINAGE WINDS CONTINUE TO AFFECT WHITTIER,
SEWARD AND VALDEZ, AND VERTICAL MIXING IS KEEPING TEMPERATURES QUITE
A BIT WARMER WHERE WINDS PERSIST, BUT WIND CHILL VALUES ARE ONLY
SLIGHTLY WARMER COMPARED TO THE FRIGID TEMPERATURES IN PLACE FARTHER
INLAND.
FOR THE OUTLOOK, LITTLE CHANGE IS EXPECTED THROUGH MID-WEEK. AN
UPPER LEVEL JET STREAK ROUNDING THE STRONG UPPER RIDGE OUT WEST WILL
SHIFT EAST INTO SOUTHCENTRAL, RESULTING IN ANOTHER TEMPORARY
INCREASE IN GAP WINDS FOR PARTS OF THE REGION. THIS SETUP DOES NOT
LOOK FAVORABLE FOR GUSTY WINDS ANYWHERE OVER INTERIOR VALLEYS,
INCLUDING THE MAT VALLEY. THE STRONGEST NORTHERLY WINDS WILL BE
ALMOST ENTIRELY FOCUSED ALONG THE COAST, INCLUDING NEAR VALDEZ,
WHITTIER, SEWARD AND MUCH OF KODIAK ISLAND. COASTAL GAP WINDS WILL
WEAKEN LATER TODAY INTO WEDNESDAY AS THE UPPER LEVEL RIDGE TO OUR
WEST MOVES OVERHEAD AND AS PREVAILING FLOW WEAKENS AND BECOMES MORE
WESTERLY WITH TIME. TEMPERATURES WILL MODERATE SLIGHTLY THROUGH
WEDNESDAY.
BY LATE WEDNESDAY INTO THURSDAY, ANOTHER TROUGH DROPPING INTO
SOUTHCENTRAL FROM THE ARCTIC WILL BRING A REINFORCING SHOT OF FRIGID
AIR INTO THE REGION. THE AK RANGE WILL RAKE THE MAJORITY OF THE
MOISTURE OUT OF THE FRONT, BUT SOME LINGERING MOISTURE MAY RESULT IN
LIGHT SNOW ACROSS THE NORTHERN SLOPES OF THE TALKEETNAS. FARTHER
EAST, LIGHT SNOW IS LIKELY FROM THE NORTHERN COPPER RIVER BASIN BY
ISABEL PASS EASTWARD THROUGH MENTASTA PASS, NABESNA, AND CHISANA AS
THIS FRONT MOVES THROUGH. THE REMAINDER OF THE AREA WILL REMAIN COLD
AND DRY. THIS TROUGH WILL REINVIGORATE THE OUTFLOW GAP WINDS IN ALL
THE USUAL PLACES INTO THE PRINCE WILLIAM SOUND AND NORTHERN GULF.
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3: TODAY THROUGH THURSDAY NIGHT)...
RELATIVELY WARMER CONDITIONS CONTINUE THROUGH WEDNESDAY. THEN,
TEMPERATURES GRADUALLY TREND LOWER AS MUCH COLDER AIR MAKES ITS
WAY SOUTH ACROSS WESTERN ALASKA AND THE BERING SEA. THURSDAY
(CHRISTMAS DAY) WILL LIKELY MARK THE RETURN OF HAZARDOUS
COLD/WINTER CONDITIONS, WITH THE POTENTIAL FOR SIGNIFICANT
VISIBILITY REDUCTIONS IN BLOWING SNOW FOR THE PRIBILOF ISLANDS,
AND WIND CHILLS DROPPING TO -30 OR BELOW FOR KUSKOKWIM DELTA AND
KUSKOKWIM VALLEY.
DIVING INTO THE DETAILS... WEAK UPPER-LEVEL SHORTWAVE TROUGHS WILL
BRING LIGHT PRECIPITATION TO KUSKOKWIM DELTA AND KUSKOKWIM VALLEY.
TEMPERATURES IN THE LOW TO MID 30S WILL RESULT IN RAIN MIXING WITH
SNOW IN THE KUSKOKWIM DELTA INTERIOR, WITH UP TO 1 INCH OF SNOW
ACCUMULATION. ALONG THE KUSKOKWIM COAST, SNOW WILL LIKELY CHANGE
OVER TO RAIN BY THIS AFTERNOON, BEFORE CHANGING BACK TO SNOW
AROUND EARLY TOMORROW MORNING AS COLDER AND DRIER AIR BEGINS TO
MOVE IN. TEMPERATURES GRADUALLY DROP ACROSS SOUTHWEST ALASKA
THROUGH THE END OF THE WEEK, WITH OVERNIGHT LOWS RANGING FROM JUST
ABOVE 0 ALONG BRISTOL BAY TO AS LOW AS -10 TO -20 DEGREES F FOR
PARTS OF KUSKOKWIM DELTA AND KUSKOKWIM VALLEY THURSDAY NIGHT. FOR
MARINERS MOVING ALONG THE KUSKOKWIM DELTA COAST, THIS COLDER AIR
WILL INCREASE THE LIKELIHOOD OF HEAVY TO PERHAPS EVEN EXTREME
FREEZING SPRAY.
FOR THE ALEUTIAN ISLANDS AND BERING SEA, A TREND TOWARDS STORMIER
CONDITIONS AS TWO LOW PRESSURE SYSTEMS GRADUALLY DISPLACE THE
RIDGE OF HIGH PRESSURE CURRENTLY OVER THE BERING SEA. THE STORM TO
WATCH WILL BE THE ONE MOVING IN ON WEDNESDAY, WHICH WILL BRING A
DECENT SLUG OF MOISTURE WITH IT. THE ALEUTIAN ISLANDS WILL STAY
WARM ENOUGH FOR PRECIPITATION TO BE MOSTLY RAIN, THOUGH THE
PRIBILOF ISLANDS AND PARTS OF THE ALASKA PENINSULA WILL LIKELY
PICK UP A FEW INCHES OF SNOW. THE CONCERN WILL BE THE POTENTIAL
FOR SIGNIFICANT VISIBILITY REDUCTIONS IN BLOWING SNOW (AND PERHAPS
EVEN BLIZZARD CONDITIONS) FOR THE PRIBILOF ISLANDS AS SNOW FALLS
IN CONJUNCTION WITH GALE FORCE WINDS ON CHRISTMAS DAY. THE BIGGEST
QUESTION HERE WILL BE AIR TEMPERATURE, AND WHETHER TEMPERATURES
WILL BE COLD ENOUGH TO SUPPORT THE TYPE OF FLUFFY, MORE LOFTABLE
SNOW THAT COULD BRING MORE INTENSE BLOWING SNOW. EITHER WAY,
UNLESS THIS STORM IS FORECAST TO TAKE A VASTLY DIFFERENT TRACK,
THERE WILL LIKELY BE STRONG WINDS AND SOME LEVEL OF BLOWING SNOW
FOR CHRISTMAS DAY FOR THE PRIBILOF ISLANDS.
-CHEN
LONG TERM FORECAST (DAYS 4 THROUGH 7: FRIDAY THROUGH MONDAY)
A POTENT SHORTWAVE DRIVES SOUTH OUT OF THE ARCTIC AND ACROSS THE
INTERIOR BEFORE DEEPENING INTO A CLOSED LOW OVER SOUTHERN ALASKA
AND THE NORTHERN GULF BY THE WEEKEND. AS THIS SYSTEM PROGRESSES
SOUTH INTO THE GULF, IT BRINGS A RENEWED THREAT FOR HIGH WINDS
LATER THIS WEEK ACROSS TYPICAL LOCATIONS, INCLUDING THE MATANUSKA
VALLEY, VALDEZ AREA/THOMPSON PASS, AND ALONG THE SOUTHERN AKPEN
AND GULF COAST. 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. MODEL AGREEMENT HAS SLIGHTLY
IMPROVED ON THE EVOLUTION OF A DEVELOPING SURFACE LOW IN THE GULF
OVER THE WEEKEND. WHILE MOST OF THE MOISTURE ASSOCIATED WITH THIS
LOW WILL BE DIRECTED TOWARDS SOUTHEAST ALASKA, SOUTHCENTRAL ALASKA
WILL SEE INCREASED CHANCES FOR SNOW AS THE LOW DRIFTS SOUTH OF
PRINCE WILLIAM SOUND. THE GREATEST CHANCE FOR SNOW WILL BE ALONG
THE GULF COAST AND PRINCE WILLIAM SOUND, WHILE CONFIDENCE REMAINS
LOW ON THE INLAND EXTENT OF SNOWFALL AS THIS WILL BE HIGHLY
DEPENDENT ON THE TRACK OF THE LOW. PERSISTENT TROUGHING IN THE
GULF LASTING THROUGH THE WEEKEND WILL ALLOW FOR ENHANCED GAP WINDS
TO CONTINUE INTO EARLY NEXT WEEK ACROSS THE EASTERN ALEUTIANS,
SOUTHERN AKPEN, AND GULF COAST. FURTHER WEST, A STRONGER RIDGE
BUILDS BACK ACROSS THE BERING SEA AS THE PATTERN REMAINS AMPLIFIED
THROUGH EARLY NEXT WEEK.
AVIATION
PANC...VFR CONDITIONS AND LIGHT WINDS WILL PERSIST THROUGH THE
PERIOD.
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