428
FXAK68 PAFC 100135
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
535 PM AKDT TUE SEP 9 2025
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
CURRENTLY, A STRONG LOW IS PRESENT WEST OF KODIAK ISLAND. A FRONT
FROM THE LOW IS ALLOWING FOR STEADY RAINFALL ACROSS THE
SOUTHCENTRAL COAST AND PRINCE WILLIAM SOUND AS WELL AS WAVES OF
RAINFALL INTO THE ANCHORAGE AND MAT-SU VALLEY REGIONS. THIS
RAINFALL IN ANCHORAGE WILL SLOWLY LIGHTEN UP BY TONIGHT AS ALOFT
EASTERLY WINDS CAUSE DOWNSLOPING TO OCCUR FROM THE CHUGACH
MOUNTAINS. KODIAK ISLAND IS SEEING RAINFALL CONTINUE AS THE LOW
INCHES EVER CLOSER TO THE AREA. WIND SPEEDS IN KODIAK ISLAND
HOWEVER, ARE DECREASING AS WINDS BECOME MORE NORTHERLY. A BARRIER
JET IS SETTING UP ALONG THE COAST NEAR CORDOVA, EXTENDING INTO
PRINCE WILLIAM SOUND AND ALL THE WAY INTO THE BARREN ISLANDS.
EASTERLY WINDS THAT ARE GALE FORCE IN STRENGTH ARE RESULTANT FROM
THE JET AND WILL SLOWLY WEAKEN INTO WEDNESDAY AS THE LOW REDUCES
IN STRENGTH. WINDS IN ANCHORAGE ARE TO BECOME BREEZY AND NORTHERLY
BEFORE TAPERING OFF THIS EVENING.
WEDNESDAY HAS THE LOW MOVE NEAR KODIAK ISLAND. CONTINUED RAINFALL
ALONG THE SOUTHCENTRAL COAST AND PRINCE WILLIAM SOUND IS EXPECTED.
WINDS WILL BE LIGHTER, BUT A LINGERING BARRIER JET NEAR CORDOVA
AND SOME DOWN-INLET GAP WINDS IN THE AUGUSTINE ISLAND AND SHELIKOF
STRAIT ARE LIKELY. THURSDAY THROUGH FRIDAY HAS THE LOW STALL OUT
AS IT SLOWLY WEAKENS. AS THIS OCCURS, ALOFT WINDS WEAKEN IN THE
ANCHORAGE AND MAT-SU VALLEY AREAS, ALLOWING DOWNSLOPING TO END AND
ALLOWING FOR STEADY RAINFALL BY THURSDAY AFTERNOON INTO FRIDAY.
DUE TO THE CONTINUED EASTERLY FLOW MENTIONED BEFORE, HEAVY
RAINFALL ALONG THE EASTERN SLOPES OF THE KENAI AND CHUGACH
MOUNTAINS WILL CONTINUE. ALL IN ALL, COMMUNITIES SUCH AS WHITTIER
COULD SEE 6 TO 10 INCHES OF RAIN BEFORE THE LOW DISSIPATES. OTHER
COASTAL AREAS COULD SEE 2 TO 4 INCHES OF RAIN. ANCHORAGE AND THE
MAT-SU VALLEY COULD SEE UP TO AN INCH OF RAIN. BY FRIDAY
AFTERNOON, THE LOW WILL BEGIN TO MOVE INLAND, WHICH WILL SPEED UP
ITS DISSOLUTION. LOOKING A BIT AHEAD INTO SATURDAY SHOWS EXACTLY
THIS. WEAK RIDGING WILL REPLACE THE LOW, LEADING TO LESS RAINFALL
AND WEAKER WINDS, BUT ANOTHER LOW APPROACHING FROM THE WEST MAY
CAUSE THE SAME STORY ALL OVER AGAIN NEXT WEEK.
-JAR
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(DAYS 1 THROUGH 3: TONIGHT THROUGH FRIDAY)...
AN OCCLUDED GALE FORCE LOW IS CENTERED ROUGHLY 100 MILES SOUTH OF
CHIGNIK THIS AFTERNOON. TO THE WEST OF THE CENTER, GALE FORCE
WINDS CONTINUE TO STREAM SOUTH ACROSS THE BERING SEA, EASTERN
ALEUTIANS, AND ALASKA PENINSULA THANKS TO A TIGHT PRESSURE
GRADIENT AND COLD AIR ADVECTION. OVER MAINLAND SOUTHWEST ALASKA,
PRECIPITATION WRAPPING THE CORE OF THE LOW IS SPREADING WIDESPREAD
LIGHT RAIN SHOWERS, WHILE CLOSER TO THE WESTERN ALASKA RANGE,
CONDITIONS ARE MOSTLY DRY AS DOWNSLOPING RESULTS FROM EAST TO
NORTHEASTERLY WINDS GUSTING AS HIGH AS 50 MPH, EVIDENT
PARTICULARLY OUT OF KAMISHAK GAP ACROSS PARTS OF BRISTOL BAY. OVER
THE WESTERN AND CENTRAL BERING SEA/ALEUTIANS, MUCH CALMER
CONDITIONS ARE ALREADY MAKING A RETURN AS HIGH PRESSURE BUILDS
INTO PLACE.
THE DETAILS OF THE FORECAST REMAIN LARGELY UNCHANGED FROM THE
PREVIOUS FORECAST. BY TONIGHT, THE LOW WILL APPROACH THE WESTERN
GULF NEAR OR JUST SOUTH OF KODIAK ISLAND, WHILE THE CORRIDOR OF
STRONG NORTHERLY FLOW BETWEEN THE LOW AND THE HIGH OUT OVER THE
WESTERN BERING ADVANCES EAST INTO THE AKPEN AND MUCH OF SOUTHWEST
ALASKA. NORTH TO NORTHWESTERLY WINDS WILL CONTINUE TO GUST UP TO
55 MPH, ESPECIALLY THROUGH AND OUT OF BAYS AND PASSES IN THE
ALASKA PENINSULA THROUGH WEDNESDAY. AN ARCTIC TROUGH DIGGING
SLOWLY OVER WESTERN ALASKA WILL PUSH A COLDER, DRIER AIR MASS INTO
SOUTHWEST ALASKA BEGINNING WEDNESDAY. AS A RESULT, PRECIPITATION
WILL CLEAR OUT RATHER ABRUPTLY FROM WEST TO EAST AS THE LOW DRIFTS
FARTHER OUT INTO THE GULF. SOME OF THE COLDEST AIR SEEN SINCE THE
SPRING WILL WORK INTO THE REGION BEGINNING WEDNESDAY NIGHT,
DROPPING LOW TEMPERATURES INTO THE MID 30S FOR MANY INLAND
LOCATIONS, WHILE THE SOUTHWEST COAST LIKELY REACHES THE LOW 40S.
HEADING INTO THURSDAY, THE LOW IN THE GULF WEAKENS MORE
SIGNIFICANTLY AND GAP WINDS SOUTH OF THE ALASKA PENINSULA DROP
BELOW GALE FORCE. HIGH PRESSURE SHIFTS INTO THE EASTERN BERING
SEA, ALLOWING WINDS TO TREND DOWN THROUGH THE END OF THE WEEK. FOR
THE CENTRAL AND WESTERN BERING SEA, A COMPLEX OF WEAK LOWS BRING
MORE UNSETTLED WEATHER IN THE FORM OF PERIODS OF RAIN SHOWERS,
THOUGH WINDS REMAIN LESS THAN 25 KNOTS. THURSDAY NIGHT INTO
FRIDAY, RAIN SHOWERS SPREAD AS FAR AS THE EASTERN ALEUTIANS AND
SOUTHERN TIP OF THE ALASKA PENINSULA. FOR SOUTHWEST ALASKA,
TEMPERATURES REMAIN COOLER, WITH LOWS IN THE 30S AND HIGHS NEAR 50
HEADING INTO THE WEEKEND.
QUESADA
LONG TERM FORECAST (SATURDAY THROUGH TUESDAY)
LONG TERM OUTLOOK REMAINS ACTIVE IN BOTH THE SOUTHCENTRAL AND
SOUTHWEST REGIONS OF ALASKA. A TROUGH LINGERS OVER THE GULF OF
ALASKA RESULTING IN TWO AREAS OF LOW PRESSURE IMPACTING
SOUTHCENTRAL THIS WEEKEND. THE FIRST, AND STRONGEST OF THE TWO,
MOVES THROUGH THE BARREN ISLAND THEN ONSHORE BRINGING RAIN AND
WINDY CONDITIONS TO THE AREA. RAINFALL AMOUNTS CURRENTLY ARE
LIGHT. THE SECOND LOW IN THE CENTRAL GULF OF ALASKA MOVES SLOWLY
NORTHWARD TOWARD HITCHINBROOK ISLAND AND THE WESTERN PRINCE
WILLIAM SOUND BRINGING RAIN TO COASTAL AREAS.
TO BEGIN THE NEXT WEEK, A STRONG LOW SLOWLY ROTATES IN THE NORTH
PACIFIC SOUTH OF THE ALASKA PENINSULA. THE FRONT ASSOCIATED WITH
THIS LOW BRINGS ANOTHER ROUND OF WIDESPREAD RAIN SHOWERS AND
STRONG WIND FORM KODIAK ISLAND TO PRINCE WILLIAM SOUND.
-JOHNSTON
AVIATION
PANC...STRENGTHENING SOUTHEASTERLY WINDS AT 2000' WILL HELP TO
DOWNSLOPE OUT MUCH OF THE PRECIPITATION ACROSS THE TERMINAL THIS
EVENING AS WELL AS TO HELP KEEP CEILINGS LARGELY AT VFR LEVELS.
BRIEF PERIODS OF MVFR CEILINGS WILL BE POSSIBLE WITH ANY RAIN THAT
DOES FALL. WIND SHEAR WILL BE THE BIGGER CONCERN WITH LIGHT
NORTHERLY SURFACE WINDS BENEATH ELEVATED SOUTHEASTERLY FLOW ALOFT.
RAIN CHANCES RETURN WEDNESDAY MORNING
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page