989
FXAK68 PAFC 240219
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
519 PM AKST TUE DEC 23 2025
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3: TODAY
THROUGH FRIDAY)...
A COLD WEATHER ADVISORY REMAINS IN EFFECT FOR THE COPPER BASIN
WHERE WIND CHILLS IN THE RANGE OF -40 TO -60 WILL CONTINUE TO BE
POSSIBLE INTO WEDNESDAY. DRAINAGE WINDS TO THE GULF COAST NEAR
SEWARD AND VALDEZ, HAVE CREATED ENOUGH VERTICAL MIXING TO WARM
CONDITIONS UP FROM THEIR MORNING LOWS, HOWEVER, BELOW NORMAL
TEMPERATURES WILL CONTINUE INTO THE NEW YEAR.
FOR THE SHORT-TERM OUTLOOK, LITTLE CHANGE IS EXPECTED UNTIL
THURSDAY WHEN 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 WILL BE UNLIKELY TO CAUSE 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. AS AN UPPER
LEVEL RIDGE TO OUR WEST MOVES OVERHEAD, COASTAL GAP WINDS WILL
CONTINUE TO WEAKEN. PREVAILING FLOW BECOMES MORE WESTERLY AND
FURTHER MODERATES TEMPERATURES 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 ALASKA RANGE WILL WRING OUT THE MAJORITY
OF THE MOISTURE FROM 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. CHANCES FOR THE NEXT MEASURABLE SNOWFALL
ARE IMPROVING FOR FRIDAY AFTERNOON, BUT FURTHER DETAILS WILL
DEPEND ON THE TRACK OF A SURFACE LOW IN THE NORTHERN GULF.
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3: TONIGHT THROUGH FRIDAY)...
HIGH PRESSURE CONTINUES TO BE CENTERED SOUTH OF THE EASTERN
ALEUTIANS, KEEPING A BUBBLE OF RELATIVELY QUIET CONDITIONS IN
PLACE ACROSS MUCH OF THE BERING SEA AND SOUTHWEST ALASKA. A LOW
TRACKING FROM THE CHUKCHI SEA ALONG THE NORTH SLOPE IS HELPING TO
DRAW WARM MOIST AIR ACROSS THE BERING SEA INTO SOUTHWEST ALASKA.
THIS HAS BROUGHT VERY LIGHT PRECIPITATION AND WIDESPREAD FOG TO
THE KUSKOKWIM DELTA, WHICH IS EXPECTED TO CONTINUE UNTIL THE COLD
FRONT ASSOCIATED WITH THE LOW DROPS SOUTH LATER TONIGHT INTO
WEDNESDAY. THE FRONT BRINGS INCREASED CHANCES FOR SOME LIGHT SNOW,
WITH ACCUMULATIONS UP TO AROUND ONE INCH, BEFORE THE COLDER,
DRIER AIR MOVES IN TO MIX OUT THE FOG AND LOW STRATUS, GIVING WAY
TO SUNNIER SKIES AND COOLING TEMPERATURES.
OUT WEST, A DEVELOPING LOW LIFTS TOWARD THE ALEUTIANS, SPREADING
PRIMARILY RAIN AND STRENGTHENING WINDS ALONG THE ISLANDS THROUGH
THURSDAY (CHRISTMAS DAY). FURTHER NORTH IN THE PRIBILOF ISLANDS,
COLDER AIR WILL MEAN PRECIPITATION THAT INITIALLY STARTS AS RAIN
WEDNESDAY NIGHT TRANSITIONS OVER TO SNOW BY THURSDAY (THOUGH
QUICKER FURTHER NORTH FOR SAINT PAUL). WINDS, WHICH INCREASE TO
GALE FORCE, WILL THEN CAUSE SIGNIFICANT VISIBILITY REDUCTIONS FOR
THE PRIBILOF ISLANDS, REDUCING VISIBILITY BELOW ONE MILE AND
POTENTIALLY EVEN LEADING TO BLIZZARD CONDITIONS. THERE IS SOME
UNCERTAINTY GIVEN THAT TEMPERATURES ARE LIKELY TO REMAIN ABOVE
FREEZING UNTIL SOMETIME CHRISTMAS DAY, WHICH CONTRIBUTES TO LOWER
CONFIDENCE ON THE START TIME OF THE WORST CONDITIONS. LATER IN THE
DAY AND INTO THURSDAY NIGHT, HOWEVER, TEMPERATURES DROPPING INTO
THE 20S WILL MAKE FOR MUCH BETTER CONDITIONS TO BLOW SNOW AROUND,
WHICH WILL REDUCE VISIBILITY TO AT LEAST HALF A MILE. VISIBILITY
INCREASES ON FRIDAY AS PRECIPITATION COMES TO AN END FROM NORTH TO
SOUTH AS COLD AIR SURGING IN FROM THE NORTH CAUSES THE FRONT
TO DROP SOUTHWARD.
FOR FRIDAY, COLD AIR SURGES SOUTH TOWARD THE ALEUTIANS AND ALASKA
PENINSULA, WITH THE FRONT ALIGNING ALONG AN AXIS FROM THE EASTERN
ALEUTIANS UP INTO PORTIONS OF BRISTOL BAY. TEMPERATURES WILL BE
LOW ENOUGH FOR THE MAJORITY OF LOCATIONS RECEIVING PRECIPITATION
TO SEE IT IN THE FORM OF ALL SNOW, WITH BLOWING SNOW BEING A
POTENTIAL CONCERN FURTHER SOUTH AND WEST, WHERE WINDS WILL BE
STRONGEST. FURTHER NORTH, TEMPERATURES WILL BE COLDER, WITH WIND
CHILLS/APPARENT TEMPERATURES DROPPING TO NEAR OR BELOW 40 DEGREES
BELOW ZERO IN THE KUSKOKWIM VALLEY AND POTENTIALLY PARTS OF THE
KUSKOKWIM DELTA AS WELL. ALONG THE SOUTHWEST COAST, THE COLD AIR
AND GALE FORCE WINDS COMBINE TO PRODUCE A HEAVY FREEZING SPRAY
HAZARD, THOUGH POTENTIAL FOR EXTREME FREEZING SPRAY APPEARS
MARGINAL AND SHORT-LIVED.
QUESADA
.LONG TERM FORECAST (DAYS 4 THROUGH 7: SATURDAY THROUGH
TUESDAY)...
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 LATER THIS
WEEK ACROSS TYPICAL LOCATIONS INCLUDING THE MATANUSKA VALLEY,
VALDEZ AREA/THOMPSON PASS, AND ALONG THE SOUTHERN AKPEN AND GULF
COAST THROUGH THE WEEKEND. ALTHOUGH MOST OF THE MOISTURE
ASSOCIATED WITH THIS LOW WILL BE DIRECTED TOWARDS SOUTHEAST
ALASKA, SOUTHCENTRAL 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. 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 SATURDAY INTO 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. 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.
AVIATION
PANC...VFR CONDITIONS AND LIGHT WINDS WILL PERSIST THROUGH THE
PERIOD.
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