642
FXAK68 PAFC 030028
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
428 PM AKDT MON JUN 2 2025
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
AN UNSETTLED WEATHER PATTERN WILL CONTINUE ACROSS SOUTHCENTRAL AS
A BROAD UPPER LEVEL LOW OVER THE BERING LIFTS INTO SOUTHWEST
ALASKA AND INTO THE INTERIOR OVER THE NEXT FEW DAYS. MULTIPLE
SHORTWAVES ARE FORECAST TO MOVE THROUGH THE BASE OF THE TROUGH AND
DOWNSTREAM INTO SOUTHCENTRAL OVER THE COURSE OF THE WEEK,
RESULTING MULTIPLE ROUNDS OF POTENTIAL PRECIPITATION. WINDS HAVE
BEEN AS ADVERTISED (WINDY!) WITH GUSTS TO 35+ MPH INTO PARTS OF
ANCHORAGE AND AS FAR NORTH AS PALMER. THE LATTER WILL SEE A KNIK
WIND INCREASE THROUGH TONIGHT WITH A CONTINUATION OF BLOWING DUST,
WHICH HAS BEEN EVIDENT ON WEBCAMS ALL DAY. PRECIPITATION WILL
REMAIN MOSTLY CONFINED TO THE COAST AND NORTHERN SUSITNA VALLEY
OWING TO STRONG DOWNSLOPING SOUTHEASTERLY FLOW OVER THE MOUNTAINS,
THOUGH SPRINKLES TO PERIODS OF VERY LIGHT RAIN ALSO REMAIN
POSSIBLE IN THE DOWNSLOPED AREAS.
FOR TUESDAY THE EASTERN EDGE OF THE UPPER LOW AND A SHORTWAVE
WILL MOVE INTO SOUTHCENTRAL, INCREASING MARINE WINDS AND GAP WINDS
ONCE AGAIN THROUGHOUT THE DAY. ONE NOTABLE CHANGE HAS BEEN MADE
WITH RESPECT TO WEST ANCHORAGE, WHERE HIRES MODELS HAVE STRONGLY
INDICATED THE TURNAGAIN ARM WIND WILL CONTINUE TO CLIP THE WEST
SIDE OF TOWN. DETERMINISTIC MODELS ALL HAVE A BROAD BERING SURFACE
LOW LIFT INTO THE YK DELTA BY TUESDAY AFTERNOON, WITH THE
CONTINUED PRESENCE OF A COAST RIDGE ALONG THE GULF COAST. THIS
APPEARS REASONABLE AND HAVE CONSEQUENTLY KEPT SOUTHEASTERLY WINDS
INTO ANCHORAGE THROUGH TOMORROW. WITH MORE UPPER LEVEL LIFT,
EXPECT MODERATE PRECIPITATION ALONG THE COAST WITH NOW LIKELY RAIN
FROM THE WESTERN KENAI NORTH INTO THE SUSITNA VALLEY. WINDS ALOFT
WILL SLOWLY VEER AND BECOME SLIGHTLY MORE SOUTHERLY, WHICH WILL
MITIGATE DOWNSLOPING AND ALLOW FOR PERIODS OF LIGHT RAIN FOR
ANCHORAGE AND THE MAT VALLEY AS WELL.
HAVE INCREASED POPS ON WEDNESDAY AS A TROUGH LIFTS THROUGH THE
WESTERN ALASKA RANGE DURING THE MORNING HOURS, QUICKLY FOLLOWED BY
ANOTHER TROUGH INTO SOUTHCENTRAL. IT STILL LOOKS LIKELY THAT JUST
ABOUT EVERYWHERE WILL GET SOME LIGHT RAIN WEDNESDAY INTO
THURSDAY, IT'S JUST A MATTER OF WHERE THE MORE MODERATE RAINFALL
WILL FALL. GAP WINDS ARE STILL FORECAST TO COME TO AN END BY LATE
WEDNESDAY/WEDNESDAY NIGHT AS THE PRESSURE GRADIENT ACROSS THE
REGION FINALLY RELAXES.
-BL/CJ
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(TODAY THROUGH WEDNESDAY)...
THE ONCE-STATIONARY LOW IN THE BERING SEA WILL CONTINUE TO MOVE
EASTWARD TOWARD THE SOUTHWEST ALASKA MAINLAND THE NEXT 12 HOURS.
A SECOND LOW MOVES SOUTHEAST AND OVER THE CENTRAL ALEUTIANS
THROUGH THIS EVENING. RAIN AND WINDY CONDITIONS WILL PERSIST
THROUGH MID-WEEK ACROSS MUCH OF SOUTHWEST ALASKA AND THE
ALEUTIANS.
A 993MB LOW IN THE BERING SEA SOUTHEAST OF THE PRIBILOF ISLANDS
REMAINS FAIRLY STATIONARY THROUGH EARLY THIS EVENING. A SECOND
LOW JUST SOUTH OF NIKOLSKI WILL DISSIPATE THIS EVENING AND MOST
OF ITS ENERGY MOVES INTO SOUTHCENTRAL ALASKA. WIND GUSTS RANGING
FROM 30 TO 50 KNOTS TODAY, HIGHEST ALONG THE PACIFIC OCEAN SIDE OF
THE ALEUTIANS, WILL SLOWLY DECREASE OVERNIGHT THOUGH TURN MORE
SOUTHWESTERLY AFTER MIDNIGHT. AS THIS SECOND LOW MOVES
SOUTHEASTWARD, IT WILL CAUSE THE BERING SEA LOW TO MOVE ONSHORE
OVERNIGHT. AS THE BERING SEA LOW MOVES TO THE MAINLAND,
SOUTHWESTERLY, ONSHORE WINDS ARE LIKELY THOUGH THEY WILL NOT BE
AS STRONG AS THE PAST FEW DAYS. WEAK ONSHORE FLOW WILL CAUSE
SCATTERED RAIN SHOWERS AND AREAS OF COASTAL FOG/MIST TONIGHT AND
TOMORROW MORNING.
TOMORROW, WIDESPREAD CLOUD COVER ACROSS THE MAINLAND IS EXPECTED
THOUGH BREAKS IN THE CLOUD COVER ARE LIKELY IN THE KUSKOKWIM
VALLEY. THESE BREAKS RESULT IN ISOLATED RAIN SHOWERS AND
THUNDERSTORMS. A FAST MOVING LOW IN THE NORTH
PACIFIC BRINGS INCREASE GAP LOCATION WINDS AND ISOLATED RAIN TO
THE ALASKA PENINSULA AND EASTERN ALEUTIANS. NORTHERLY WINDS SHIFT
MORE NORTHWESTERLY AS THE DAY PROGRESSES ON WEDNESDAY AS HIGH
PRESSURE BEGINS TO BUILD IN FROM THE WESTERN BERING.
-JOHNSTON
LONG TERM FORECAST (DAYS 4 THROUGH 7: FRIDAY THROUGH MONDAY)
NO SIGNIFICANT CHANGE FROM PREVIOUS DISCUSSION. THE PERSISTENT
LONGWAVE TROUGH ACROSS THE BERING AND ALEUTIANS WILL BECOME MORE
ZONAL AND LIFT ACROSS SOUTHCENTRAL WITH SEVERAL EMBEDDED
SHORTWAVES ROTATING AROUND THE MAIN TROUGH AXIS. THE POSITIONING
AND ORIENTATION OF THE TROUGH WILL KEEP A FAVORABLE STORM TRACK
FOR SOUTHCENTRAL, WHICH WILL CONTINUE TO SUPPORT COOLER AND WETTER
THAN AVERAGE WEATHER CONDITIONS FOR THE LONG TERM. MODEL GUIDANCE
SUGGESTS ONE WAVE OF LOW PRESSURE MOVES INTO SOUTHCENTRAL
WEDNESDAY AFTERNOON. A BREAK FROM PRECIPITATION MAY OCCUR ON
FRIDAY FOR THE REGION BETWEEN SYSTEMS, THOUGH ANY CLEARING/DAYTIME
HEATING WILL PRESENT A CHANCE FOR AFTERNOON THUNDERSTORMS.
ANOTHER SYSTEM WORKS INTO THE AREA FOR SATURDAY AND SUNDAY.
-DD
AVIATION
PANC...VFR CONDITIONS WILL PERSIST THROUGH TUESDAY MORNING.
SOUTHEAST WINDS OUT OF THE TURNAGAIN ARM WILL RETURN THIS
AFTERNOON THROUGH TONIGHT WITH GUSTS TO AROUND 25 TO 30 KTS.
SIMILARLY, WINDS DECREASE BRIEFLY TUE MORNING, THEN RETURN TO THE
TERMINAL FOR THE AFTERNOON. MVFR CHANCES INCREASE ALONG WITH RAIN
BECOMING LIKELY TUE AFTERNOON.
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