946
FXAK68 PAFC 020115
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
515 PM AKDT FRI MAY 1 2026
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA
(DAYS 1 THROUGH 3: THIS AFTERNOON THROUGH MONDAY EVENING)...
TODAY HAS BEEN AN ACTIVE DAY IN THE WEATHER DEPARTMENT ACROSS
PORTIONS OF SOUTHCENTRAL ALASKA AS A FRONTAL SYSTEM CONTINUES TO
PUSH TOWARDS PRINCE WILLIAM SOUND. THE AIRMASS OVERHEAD WAS
SOMEWHAT COOLER AND WITH HEAVY PRECIPITATION FALLING, COLD AIR WAS
ABLE TO MAKE IT DOWN TO THE SURFACE. THIS WAS THE CASE FOR
WHITTIER, PORTAGE, AND TURNAGAIN PASS WHERE SNOW FELL FOR MOST OF
THE DAY. THIS SNOW, HEAVY AT TIMES, IN CONJUNCTION WITH GUSTY
SOUTHEAST WINDS, HAS CAUSED REDUCED VISIBILITY, ESPECIALLY THROUGH
TURNAGAIN PASS AND PORTAGE VALLEY. A WINTER WEATHER ADVISORY HAS
BEEN ISSUED TO ADDRESS VISIBILITIES BEING REDUCED DOWN TO ONE-HALF
MILE AT TIMES THROUGH TURNAGAIN PASS AND PORTAGE VALLEY THROUGH
11PM AKDT TONIGHT.
VALDEZ HAS RECENTLY TURNED OVER TO A RAIN/SNOW MIX. AS A HEAVIER
PUSH OF MOISTURE ARRIVES THIS EVENING INTO TONIGHT, IT IS EXPECTED
THAT THEY WILL ALSO TURN FULLY OVER TO SNOW. THOMPSON PASS WILL
ALSO REMAIN SNOW THROUGH THE REST OF TODAY AND INTO SATURDAY
MORNING. A SPECIAL WEATHER STATEMENT REMAINS ISSUED TO BRING
AWARENESS TO THE REDUCED VISIBILITIES AND STEADY SNOW ALONG THE
PASS THROUGH EARLY SATURDAY MORNING.
THE OTHER STORY WITH THIS STORM SYSTEM HAS BEEN THE GUSTY
SOUTHEAST WINDS. WINDS ALONG THE ANCHORAGE HILLSIDE HAVE GUSTED
AS HIGH AS 70 MPH WITH WINDS ATOP FLATTOP MOUNTAIN GUSTING AROUND
85 MPH TODAY. SOUTHEAST WINDS THROUGH THE KNIK VALLEY HAVE GUSTED
AROUND 55 MPH WITH 45 MPH GUSTS THROUGH THE COPPER VALLEY. WINDS
ACROSS THE ANCHORAGE BOWL HAVE BEEN LARGELY BEEN OUT OF THE
NORTHWEST. HOWEVER, AS AN UPPER-LEVEL MOVES OVERHEAD AND NORTH OF
THE AREA BY EARLY THIS EVENING, WINDS WILL TURN SOUTHEAST AND
BECOME GUSTY. A SPECIAL WEATHER STATEMENT HAS BEEN ISSUED FOR THE
ANCHORAGE BOWL, HILLSIDE, AND THE LOWER MATANUSKA VALLEY TO BRING
FURTHER AWARENESS TO THE STRONG GUSTY SOUTHEAST WINDS. THE
STRONGEST OF THE WINDS FOR THE HILLSIDE AND LOWER MATANUSKA
VALLEY, INCLUDING PALMER, WILL OCCUR NOW THROUGH LATE THIS EVENING
BEFORE SLOWLY DIMINISHING OVERNIGHT. THE GUSTIEST SOUTHEAST WINDS
ACROSS THE ANCHORAGE BOWL WILL OCCUR EARLY THIS EVENING THROUGH
LATE EVENING BEFORE SLOWLY DIMINISHING. EVEN THOUGH SOUTHEAST
WINDS WILL DIMINISH, THEY WILL STILL PERSIST ACROSS ANCHORAGE
THROUGH SATURDAY.
THE FORECAST BECOMES MORE UNCERTAIN HEADING INTO SATURDAY EVENING
THROUGH MONDAY REGARDING THE PROGRESSION OF ANOTHER FRONTAL
SYSTEM AND MOISTURE PLUME AND THE TRACK OF ANOTHER SURFACE LOW
THROUGH THE GULF. THE FIRST SYSTEM, THE FRONT AND MOISTURE PLUME,
LOOKS TO LIFT NORTH THROUGH THE GULF. THE UNCERTAINTY IS THE SPEED
AT WHICH IT DOES SO. THE CANADIAN AND EUROPEAN GUIDANCE HAVE A
QUICKER PROGRESSION BRINGING RAIN TO KODIAK ISLAND BY EARLY
SATURDAY EVENING AND ADVANCING THE MOISTURE TO THE KENAI COAST AND
NORTHERN GULF COAST AS SOON AS EARLY SUNDAY MORNING. THE GFS AND
NAM ARE SLOWER IN THE PROGRESSION WITH RAIN NOT MAKING IT TO
KODIAK ISLAND UNTIL SATURDAY NIGHT AND TO THE REST OF THE COAST BY
MID-MORNING SUNDAY. THE CANADIAN GUIDANCE IS THE QUICKEST WITH
THE TRACK OF A SURFACE LOW TO THE SOUTHWESTERN GULF BY MONDAY
MORNING WHILE THE GFS, NAM, AND EUROPEAN ALL TRACK THE LOW INTO
SOUTHWEST GULF BY MONDAY AFTERNOON. THE TREND WITH THIS FORECAST
PACKAGE IS MORE TOWARD THE GFS WITH THESE FEATURES FOR SATURDAY
EVENING THROUGH MONDAY AS IT LINES UP BETTER WITH ENSEMBLE
GUIDANCE. STAY TUNED FOR FORECAST UPDATES AS THE FALL-LIKE PATTERN
CONTINUES.
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3)...
CURRENTLY, MODERATE RAINFALL CONTINUES TO OVERSPREAD THE BRISTOL
BAY AREA, WITH LIGHTER RAIN/SNOW FALLING ALONG THE KUSKOKWIM COAST
WITH ALL RAIN FARTHER INLAND. THE "WINNERS" OF RAINFALL WITH THIS
SYSTEM LOOKS TO BE ANYWHERE FROM THE DILLINGHAM AREA NORTHWARD TO
THE SOUTHERN FACING WINDWARD SLOPES OF THE KUSKOKWIM MOUNTAINS,
WHERE UPSLOPE ENHANCEMENT HAS INCREASED QPF TOTALS. IN LEE OF THE
MOUNTAINS, DOWNSLOPE DRYING HAS LIMITED PRECIPITATION INTENSITY
TODAY. THIS SLUG OF MOISTURE IS DUE TO A BROAD, AND RELATIVELY
WEAK AREA OF LOW PRESSURE NOW SITUATED ABOUT HALFWAY BETWEEN THE
PRIBILOF ISLANDS AND BRISTOL BAY. AS THIS LOW WORKS NORTHEASTWARD
TOWARDS SOUTHWEST ALASKA WITH ASSOCIATED UPPER LEVEL SHORTWAVES,
RAIN CHANCES WILL LINGER THROUGH SATURDAY. SOME OF THE HIGHER
RESOLUTION GUIDANCE INDICATES THAT TEMPERATURES WILL DROP TO NEAR
FREEZING SATURDAY MORNING ACROSS MUCH OF SOUTHWEST ALASKA, WHICH
COULD MEAN A PERIOD OF SNOWFLAKES MIXING IN WITH RAINFALL OR A
SHORT LIVED PERIOD OF LIGHT, NON-IMPACTFUL SNOWFALL WITH LITTLE TO
NO ACCUMULATION.
AS THE CURRENT SYSTEM AT HAND DISSIPATES AND OPENS TO A WEAK
TROUGH ACROSS SOUTHWEST ALASKA SOMETIME LATE SATURDAY, STRONG
SURFACE RIDGING BUILDS ACROSS THE BERING AS A NEW SYSTEM MOVES
NORTHWARD FROM THE NORTH PACIFIC, SOUTH OF THE ALASKA PENINSULA.
THE GLOBAL MODELS SHOW DISAGREEMENT AMONG TIMING/PLACEMENT OF ITS
FRONT THAT WILL MOVE WAY OUT AHEAD OF THE LOW ITSELF, WHICH WILL
LARGELY IMPACT HOW MUCH RAIN SOUTHWEST ALASKA WILL RECEIVE FROM
THIS SYSTEM. GENERALLY SPEAKING, THE EASTERN PORTIONS OF SOUTHWEST
ALASKA CURRENTLY HAVE THE BEST CHANCE TO SEEING RAIN FROM THIS
NEW STORM SYSTEM, AND DEPENDING ON WHAT MODEL YOU LOOK AT,
TIMEFRAME COULD RANGE ANYTIME FROM SUNDAY EVENING TO MONDAY
MORNING. FROM HERE, MODEL CONSENSUS DEGRADES CONSIDERABLY.
MEANWHILE, A KAMCHATKA LOW WITH AN ATTENDANT/WEAKENING GALE FORCE
FRONT ARRIVES TO THE WESTERN ALEUTIANS MIDDAY SUNDAY TO SUNDAY
AFTERNOON. WITH STRONG SURFACE HIGH PRESSURE IN CONTROL ACROSS THE
BERING BLOCKING INCOMING SYSTEMS, THE TREND IN THE MODELS WITH
THIS FRONT IS TO PUSH IT FARTHER SOUTHWARD MORE QUICKLY, WITH THE
LOW AND FRONT SOLIDLY MOVING SOUTH OF THE ALEUTIAN CHAIN MONDAY
MORNING. HIGH PRESSURE MOVES IN IN THE WAKE OF THIS LOW/FRONT,
WITH ALL ATTENTION SHIFTING EASTWARD TO THE AFOREMENTIONED NORTH
PACIFIC LOW/FRONT THAT WILL IMPACT SOUTHWEST ALASKA.
-AM
.LONG TERM FORECAST (DAYS 4 THROUGH 7: TUESDAY THROUGH
FRIDAY)...
RAIN SHOULD BE ONGOING ACROSS PARTS OF SOUTHWEST AND SOUTHCENTRAL
ALASKA ON TUESDAY FROM A INLAND MOVING FRONT ON MONDAY. THE
PARENT LOW WILL EVENTUALLY MOVE INTO PRINCE WILLIAM SOUND LATER ON
TUESDAY, PROLONGING RAIN SHOWERS ACROSS THE REGION. BEYOND DAY 4
A BROAD UPPER TROUGH WILL OVERTAKE THE SOUTHERN GULF THROUGH THE
END OF THE WEEK. SOUTHWEST ALASKA WILL LIKELY EXPERIENCE A COUPLE
OF DRY DAYS ON WEDNESDAY AND THURSDAY AS HIGH PRESSURE EXPANDS
INTO THE MAINLAND FROM THE BERING. SOUTHCENTRAL ALASKA, HOWEVER,
MAY STILL SEE ISOLATED TO SCATTERED RAIN CHANCES LINGER THROUGH
THURSDAY. THE NEXT NORTH PACIFIC LOW THEN LIFTS ACROSS THE GULF
INTO SOUTHERN ALASKA ON FRIDAY WITH RENEWED RAIN CHANCES FOR BOTH
SOUTHWEST AND SOUTHCENTRAL.
BL
AVIATION
PANC...LOW LEVEL WIND SHEAR IS EXPECTED TO PERSIST A FEW MORE HOURS
WITH THE NORTHWESTERLY SURFACE WINDS AND AN ABRUPT SHIFT TO
STRONG SOUTHEASTERLY WINDS IN THE 1000 FT TO 3000 FT ABOVE THE
SURFACE LEVEL. THIS WILL END LATER THIS EVENING WHEN THE TURNAGAIN
ARM WINDS ARE ABLE TO WORK OVER THE AIRPORT AND MAKE WINDS
SOUTHEASTERLY AT ALL LEVELS. SOUTHEAST WINDS WILL BECOME MORE
SOUTHERLY BY SATURDAY MORNING AS ADDITIONAL WIND FLOWS UP COOK
INLET. VFR CONDITIONS TO PERSIST THROUGH MOST OF THE TAF PERIOD.
BRIEF DROPS TO MVFR WILL BE POSSIBLE WITHIN SHOWERS AFTER 04Z
THROUGH SATURDAY MORNING.
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