950
FXAK68 PAFC 190014
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
414 PM AKDT THU SEP 18 2025
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3: TODAY
THROUGH SATURDAY NIGHT)...
RADAR IMAGERY THIS AFTERNOON DEPICTS WIDESPREAD RAINFALL ACROSS
THE KENAI PENINSULA AND PRINCE WILLIAM SOUND AS A TROUGH IN THE
GULF CONTINUES TO LIFT NORTH. WEAK CROSS-BARRIER FLOW IS ALLOWING
FOR SHOWERS TO SPILL OVER THE TERRAIN INTO ANCHORAGE AND THE
WESTERN KENAI PENINSULA, AND WILL LIKELY CONTINUE TO DO SO WITH
EACH SUCCESSIVE WAVE THAT PASSES OVERHEAD AS MOIST SOUTHERLY FLOW
CONTINUES INTO THE BEGINNING OF THE WEEKEND. WHILE PRECIPITATION
ACCUMULATIONS SPREADING INLAND ARE EXPECTED TO BE FAIRLY LIGHT,
THIS PATTERN REMAINS FAVORABLE FOR PERSISTENT LIGHT TO MODERATE
RAINFALL FOR COASTAL AREAS IN PRINCE WILLIAM SOUND AND ALONG THE
EASTERN KENAI PENINSULA THROUGH FRIDAY NIGHT.
BY LATE FRIDAY NIGHT INTO SATURDAY MORNING, MORE COHERENT LOW
PRESSURE TRACKS ACROSS THE SOUTHERN GULF, WEAKENING THE SOUTHERLY
FLOW ALONG THE NORTH GULF COAST OR EVEN SHIFTING FLOW TO WEAK
NORTHERLY ACROSS SOUTHCENTRAL. THIS REVERSAL OF FLOW WILL RESULT
IN A DRYING TREND BOTH ALONG THE COAST AND INLAND FOR SATURDAY.
THE BREAK IN ACTIVE WEATHER WILL BE SHORT LIVED AS THE PATTERN
CONTINUES TO PROGRESS WITH THE NEXT UPPER LEVEL TROUGH PIVOTING
ACROSS THE ALASKA PENINSULA INTO THE GULF FOR SUNDAY. RAIN AGAIN
LOOKS TO FILL IN ACROSS MUCH OF SOUTHCENTRAL AS THE FORMATION OF
WEAK LOW PRESSURE IN THE NORTHERN GULF AND EAST TO SOUTHEASTERLY
FLOW ALOFT KEEPS THE REGION UNSETTLED THROUGH THE END OF THE
WEEKEND.
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3)...
A VERTICALLY STACKED LOW PRESSURE SYSTEM CURRENTLY SITS JUST
SOUTH OF THE PRIBILOF ISLANDS BEFORE TRACKING TOWARD BRISTOL BAY
OVERNIGHT. THE ASSOCIATED FRONTAL BOUNDARY WILL PUSH SHOWERY
PRECIPITATION AND SOUTHERLY WINDS ACROSS THE ALASKA PENINSULA AND
BRISTOL BAY REGION THROUGH TONIGHT. A TROUGH RIDING WITHIN THE
UPPER LEVEL JET SOUTH OF THE ALEUTIAN CHAIN WILL AMPLIFY THE
PATTERN, EVENTUALLY PULLING THE SYSTEM INTO THE WESTERN GULF
TOMORROW EVENING. NORTHERLY WINDS WILL INCREASE ON THE BACKSIDE OF
THE LOW THROUGH FAVORED BAYS AND PASSES OF THE ALEUTIAN ISLANDS.
MEANWHILE, A ROBUST UPPER LEVEL SHORTWAVE DROPS DOWN FROM THE
NORTH, USHERING IN COOLER AIR ACROSS THE BERING SEA AND ALEUTIANS.
COLD AIR ADVECTION WILL AID IN FURTHER ENHANCING NORTHERLY GAP
WINDS AS THE CORE OF STRONG WINDS SHIFTS OVER THE ALASKA
PENINSULA. GUSTS OVER 40 KNOTS ARE EXPECTED THROUGH BAYS AND
PASSES BY SUNDAY AFTERNOON. FOG AND LOW STRATUS ARE POSSIBLE OVER
THE WESTERN ALEUTIANS BY SUNDAY WHILE GENERALLY QUIET WEATHER WILL
PERSIST ACROSS INTERIOR SOUTHWEST, AK.
.LONG TERM FORECAST (DAYS 4 THROUGH 7: MONDAY THROUGH
THURSDAY)...
MINOR CHANGES FROM PREVIOUS DISCUSSION... UPPER LEVEL LOW
PRESSURE CONTINUES TO LINGER IN THE GULF OF ALASKA FROM THE
WEEKEND THROUGH MID-WEEK. SHORTWAVE TROUGHS AND EMBEDDED SURFACE
LOWS WILL BRING ENHANCED PERIODS OF RAIN AND WIND TO THE NORTH
GULF COAST. THE HEAVIEST RAIN AND STRONGEST WINDS LOOK TO STAY IN
THE PANHANDLE, BUT PRINCE WILLIAM SOUND AND THE EASTERN KENAI
PENINSULA WILL SEE PLENTY OF MOISTURE AND WIND IN COASTAL WATERS
AS WELL. THERE IS SOME UNCERTAINTY IN THE ORIENTATION OF THE LOW
AS IT PROGRESSES THROUGH THE BEGINNING OF THE WEEK, WHICH WILL
GREATLY IMPACT THE ABILITY FOR SHOWERS TO DEVELOP ACROSS INLAND
AREAS. THE SUGGESTION OF SOUTHWESTERLY UPPER LEVEL FLOW WOULD BE
FAVORABLE FOR PRECIPITATION UP COOK INLET AND INTO THE MAT-SU
VALLEYS, THOUGH RAIN SHOULD REMAIN RELATIVELY LIGHT IN THESE AREAS
IF IT DOES DEVELOP.
PERSISTENT NORTHERLY FLOW ACROSS WESTERN ALASKA AND THE BERING
SEA WILL BRING A COOLING TREND TO THE REGION AS OVERNIGHT LOWS ARE
EXPECTED TO DIP INTO THE 30'S FOR PORTIONS OF SOUTHWEST ALASKA.
THE COMBINATION OF COLD AIR ADVECTION AND A TIGHT PRESSURE
GRADIENT WILL BRING GUSTY WINDS THROUGH GAPS AND PASSES OF THE
ALASKA PENINSULA AND EASTERN ALEUTIANS ON SUNDAY TO MONDAY AND
AGAIN ON TUESDAY AND WEDNESDAY AND ANOTHER BERING SEA LOW PASSES
ALONG THE ALEUTIANS AND AKPEN THROUGH THE END OF THE PERIOD. THE
REST OF SOUTHWEST REMAINS DRY FOR THE REMAINDER OF THE LONG TERM
FORECAST PERIOD.
AVIATION
PANC...VFR CONDITIONS WILL PERSIST THROUGH THE DAY TODAY BEFORE
POSSIBLE DEGRADATION TONIGHT. WINDS WILL BE GENERALLY OUT OF THE
NORTH AND LIGHT; HOWEVER, THERE MAY STILL BE AN ISOLATED SOUTHEAST
GUST THROUGH MID-AFTERNOON TODAY AS A WEAK TROUGH LIFTS NORTH OF
THE AREA. ISOLATED SHOWERS REMAIN THIS AFTERNOON BEFORE AN
INCREASE IN COVERAGE OVERNIGHT. CEILINGS SHOULD LOWER TONIGHT AS
WELL INTO MVFR OR POSSIBLY EVEN IFR TERRITORY AS THE LOWER
ATMOSPHERE SATURATES WITH MORE WIDESPREAD PRECIPITATION.
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