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FXAK68 PAFC 031409
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
509 AM AKST TUE MAR 3 2026
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH
3/TODAY THROUGH THURSDAY NIGHT)...
THE WELL-ADVERTISED ARCTIC TROUGH REMAINS ANCHORED OVER MAINLAND
ALASKA. AS A RESULT, CLEAR AND COLD CONDITIONS HAVE PERSISTED
OVERNIGHT ACROSS SOUTHCENTRAL WITH LOW TEMPERATURES IN THE SINGLE
DIGITS WHERE GAP WINDS CONTINUE TO WELL BELOW ZERO FOR INTERIOR
SOUTHCENTRAL.
A SHORT-WAVE TROUGH OVER THE SEWARD PENINSULA THIS MORNING IS
DIGGING SOUTHWARD AND REPRESENTS ONE OF THE KEY FEATURES WILL
WILL LEAD TO A SHIFT IN THE PATTERN OVER THE NEXT FEW DAYS.
MEANWHILE, PROGRESSIVE YET AMPLIFIED FLOW PREVAILS ACROSS THE
NORTH PACIFIC. A DEEPENING LOW IN THE NORTHEAST PACIFIC CONTINUES
TO LIFT NORTHWARD TOWARD THE GULF OF ALASKA, WITH STRONGER WINDS
AND PRECIPITATION SPREADING INTO THE SOUTHERN GULF. GAP WINDS
WILL PERSIST ALONG THE GULF COAST AND PRINCE WILLIAM SOUND TODAY
AS THE LOW ADVANCES NORTHWARD.
COLD WEATHER PRODUCTS REMAIN IN EFFECT THROUGH LATE THIS MORNING
DUE TO LOW WIND CHILLS ALONG THE COAST AND COLD AIR TEMPERATURES
IN THE COPPER BASIN. TUESDAY NIGHT INTO WEDNESDAY, A STRONG,
NEGATIVELY TILTED TROUGH WILL CROSS THE GULF AND MOVE OVER
SOUTHCENTRAL. AS A RESULT, EXPECT A SECONDARY SURFACE LOW TO FORM
AHEAD OF THIS SHORT-WAVE OVER THE NORTHEASTERN GULF TONIGHT WITH
PRECIPITATION TO SPREAD FARTHER NORTH AND WEST FROM THE GULF
TOWARD CORDOVA AND THE SOUTHEASTERN COPPER RIVER BASIN.
GUIDANCE CONTINUES TO SHOW SNOW MOVING FROM EAST OF CORDOVA NORTH
INTO THE SOUTHEASTERN COPPER RIVER BASIN TUESDAY NIGHT INTO
WEDNESDAY, WITH SEVERAL INCHES OF SNOW LIKELY FOR MCCARTHY. THERE
WILL BE A SHARP CUTOFF IN PRECIPITATION ALONG THE WESTERN
PERIPHERY OF THE TROUGH. HOWEVER, WHERE THIS SETS UP IS STILL A
CHALLENGE GIVEN MODEL UNCERTAINTY. THE GFS, THE FARTHER WEST
SOLUTION, HAS SHIFTED SLIGHTLY EAST OVERNIGHT. AS SUCH, LIGHT SNOW
MAY BRIEFLY MAKE IT TO CORDOVA, THOMPSON PASS, AND GLENNALLEN.
HOWEVER, ANY SNOW THAT DOES FALL WILL LIKELY BE VERY LIGHT, WITH
ONLY AN INCH OR LESS OF ACCUMULATION. THE CLOUD COVER AND
PRECIPITATION WILL HELP MODERATE TEMPERATURES IN EASTERN PORTIONS
OF SOUTHCENTRAL. THE COLD AIRMASS WILL REMAIN MORE ENTRENCHED
ACROSS THE REMAINDER OF SOUTHCENTRAL, THOUGH THE SHIFT TO
SOUTHERLY FLOW ALOFT WILL BEGIN TO WARM THE AIRMASS A BIT. THUS,
EXPECT A SLOW WARMING TREND OVER THE NEXT COUPLE DAYS AFTER,
PERHAPS, ONE MORE VERY COLD NIGHT FROM THE WESTERN KENAI PENINSULA
NORTH TO THE MAT-SU VALLEYS.
MEANWHILE, THE AFOREMENTIONED SHORT-WAVE OVER THE SEWARD PENINSULA
WILL DIG SOUTHWARD ACROSS WESTERN AK AND DEVELOP INTO AN UPPER LOW
TONIGHT BEFORE STALLING OVER SOUTHWEST AK WEDNESDAY THROUGH
THURSDAY. THE SUBTROPICAL JET STREAM IN THE PACIFIC WILL THEN
REORIENT FROM THE NORTH PACIFIC TO THE GULF AND HELP STEER STORM
SYSTEMS QUICKLY ACROSS THE GULF. THE FIRST LOW WILL ARRIVE
WEDNESDAY NIGHT AND THURSDAY. MODEL SPREAD IS FAIRLY LARGE WITH
THE TRACK OF THE LOW, BUT IT LOOKS LIKE IT WILL LARGELY REMAIN OUT
OVER THE GULF OFFSHORE WATERS WITH LITTLE OR NO IMPACT ON LAND
AREAS. SHORT- WAVES ROUNDING THE NEWLY ESTABLISHED UPPER LOW OVER
SOUTHWEST AK WILL ROTATE INTO SOUTHCENTRAL, BRINING A CHANCE OF
LIGHT SNOW. UNCERTAINTY IN THE POSITION OF THE UPPER LOW AND TRACK
OF SHORT- WAVES MAKES IT DIFFICULT TO IDENTIFY THE AREAS MOST
LIKELY TO SEE SNOW. BOTTOM LINE, A SHIFT IN PATTERN WILL OCCUR AS
WE HEAD THROUGH THE WORK WEEK, LEADING TO WARMING TEMPERATURES AND
INCREASING CHANCE OF SNOW LATER IN THE WEEK.
-SEB/TM
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3: TONIGHT THROUGH WEDNESDAY)...
ACROSS THE REGION, WIND CHILLS ARE IN THE NEGATIVE TEENS TO -20S.
EARLY THIS MORNING, WIND CHILLS DIPPED INTO THE NEGATIVE 30S, BUT
ARE NO LONGER EXPECTED TO REACH ADVISORY LEVELS. A VERY
CONSISTENT AND RESILIENT PATTERN REMAINS IN PLACE ACROSS THE
BERING AND SOUTHWEST, WITH MUCH BELOW AVERAGE TEMPERATURES AND
COLD, NORTHEASTERLY FLOW STILL DOMINATING THE BROADER PICTURE.
CLEAR SKIES OVER SOUTHWEST ALASKA TO PERSIST THROUGH THURSDAY,
WITH THE NEXT POTENTIAL ACTIVE SYSTEM APPROACHING LATE THURSDAY
INTO FRIDAY.
ACROSS THE BERING AND ALEUTIANS, OCEAN-EFFECT SNOW SHOWERS REMAIN
ONLY OVER THE WESTERN-MOST ALEUTIANS. NORTHEAST WINDS IN SMALL
CRAFT RANGE CONTINUE TO AFFECT ALMOST THE ENTIRETY OF THE THE
BERING, SUPPORTED BY COLD ADVECTION OFF OF THE ICE EDGE ALONG WITH
A TIGHT GRADIENT BETWEEN A STRONG SIBERIAN HIGH AND NORTH PACIFIC
LOW SOUTH OF THE ALEUTIANS. TEMPERATURES IN THE 10S TO 20S
COMBINED WITH THE BRISK NORTHEASTERLIES ARE SUPPORTING AREAS OF
HEAVY FREEZING SPRAY CLOSE TO THE ICE EDGE, WHICH IS NOW COMING
VERY CLOSE TO REACHING SAINT PAUL.
BY LATE WEDNESDAY MORNING, A LOW DEPARTING KAMCHATKA RUSSIA WILL
MOVE OVER THE WESTERN BERING AND ALEUTIANS INCLUDING SHEMYA. THIS
SYSTEM MAY BRING A PERIOD OF GALE-FORCE WINDS AND SNOWFALL OVER
THE ISLANDS. SNOWFALL WILL BE INTENSIFYING LOCALLY, AND SPREADING
STEADILY EASTWARD THROUGH THURSDAY EVENING, EVENTUALLY REACHING
THE ALASKA PENINSULA BY LATE THURSDAY NIGHT/FRIDAY MORNING. THIS
MAY BRING A QUICK SHOT OF SNOWFALL TO COMMUNITIES ALONG THE AKPEN
INTO BRISTOL BAY THROUGH FRIDAY MORNING. WIND SPEEDS DO NOT LOOK
INITIALLY IMPRESSIVE WITH THIS SYSTEM, SO WHILE AREAS OF BLOWING
SNOW ARE POSSIBLE, WIDESPREAD SIGNIFICANT BLOWING SNOW IS NOT
CURRENTLY ANTICIPATED.
-CL
LONG TERM FORECAST (DAYS 4 THROUGH 7 - FRIDAY THROUGH MONDAY)
MINOR CHANGES TO PREVIOUS DISCUSSION... UPPER-LEVEL TROUGHING
CENTERED OVER THE STATE MID TO LATE THIS WEEK WILL EXTEND SOUTH
INTO THE NORTHERN PACIFIC, WITH MULTIPLE SHORTWAVES ROTATING
AROUND THE TROUGH. SOME MODEL DIFFERENCES IN THE POSITION AND
TRACK OF RESULTING SURFACE LOWS LIFTING INTO THE GULF WILL
CONTINUE TO KEEP THE PRECIPITATION FORECAST CONFIDENCE BELOW
AVERAGE FOR THE LONG TERM. A LEAN TOWARDS THE GFS ENSEMBLES BRINGS
A SHORTWAVE OVER THE WESTERN ALEUTIANS BY MID TO LATE WEEK WITH A
SHOT OF COLDER TEMPERATURES DROPPING SOUTHWARD OUT OF NORTHEAST
RUSSIA AND INTO THE WESTERN BERING. A NORTH PACIFIC LOW LIFTS INTO
THE GULF BY THURSDAY AFTERNOON, BRINGING INCREASED SNOW CHANCES
ACROSS THE NORTHERN GULF COAST AND PRINCE WILLIAM SOUND WITH THE
POTENTIAL FOR SNOW SHOWERS TO OVERSPREAD INLAND LOCATIONS OF
SOUTHCENTRAL THROUGH SATURDAY. ADDITIONALLY, STRONG NORTHWESTERLY
FLOW AND COLD AIR ADVECTION BEHIND THE GULF LOW WILL LEAD TO THE
POTENTIAL FOR STRONG GAP WINDS ACROSS THE BARREN ISLANDS AND
SOUTHERN ALASKA PENINSULA.
WHILE FORECAST CONFIDENCE IS LOW WITH REGARD TO WHERE SURFACE
FEATURES AND PRECIPITATION ULTIMATELY DEVELOP, FORECAST CONFIDENCE
IS HIGH THAT BOTH SOUTHWEST AND SOUTHCENTRAL ALASKA WILL CONTINUE
TO SEE BELOW NORMAL TEMPERATURES THROUGH THE END OF THIS WEEK.
AVIATION
PANC...VFR CONDITIONS AND LIGHT WINDS WILL PERSIST.
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