420
FXAK68 PAFC 290016
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
416 PM AKDT FRI MAR 28 2025
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA
(DAYS 1 THROUGH 3: THIS AFTERNOON THROUGH MONDAY EVENING)...
CURRENTLY, SKIES HAVE BECOME OVERCAST ACROSS THE ANCHORAGE AREA,
KENAI PENINSULA, AND ACROSS THE COAST, WITH BREAKS IN THE CLOUDS
OVER THE COPPER RIVER BASIN. GULF MOISTURE CONTINUES TO BE PULLED
NORTHWARD OVER SOUTHCENTRAL THIS AFTERNOON AS THE AREA IS BETWEEN
A BIG RIDGE IN THE BERING SEA AND ANOTHER RIDGE ACROSS SOUTHEAST
ALASKA TO GO ALONG WITH A TROUGH ACROSS INTERIOR ALASKA. A WEAK
AREA OF LOW PRESSURE IN THE WESTERN GULF, SOUTH OF MIDDLETON
ISLAND WILL CONTINUE TO PIVOT WESTWARD AND EVENTUALLY
SOUTHWESTWARD THROUGH THE REST OF TODAY AND SATURDAY AS IT
WEAKENS. WITH SURFACE HIGH PRESSURE ACROSS THE INTERIOR AND THE
LOW IN THE GULF, EXPECT NORTHERLY GAP WINDS TO PERSIST TONIGHT AND
INTO SATURDAY. THE PRECIPITATION ASSOCIATED WITH THE GULF LOW
DOES NOT LOOK TO BE SIGNIFICANT AND MOSTLY LIGHT IN NATURE. MOST
PRECIPITATION WILL FALL ALONG THE COAST OF THE EASTERN KENAI
PENINSULA, WESTERN PRINCE WILLIAM SOUND, AS WELL AS KODIAK ISLAND.
HOWEVER, AS THE UPPER-LEVEL SHORTWAVE TROUGH OVER THE CENTRAL
INTERIOR MOVES EASTWARD EARLY SATURDAY MORNING, THERE COULD BE
ENOUGH LIFT TO PRODUCE A FEW FLURRIES TO LIGHT SNOW SHOWERS EARLY
SATURDAY MORNING. THE BEST CHANCE WOULD BE ALONG THE EAST SIDE OF
TOWN AS WELL AS ALONG THE HILLSIDE. THIS SAME UPPER-LEVEL FEATURE
COULD ALSO PRODUCE SOME LIGHT SNOW ACROSS THE COPPER RIVER BASIN
SATURDAY MORNING AS WELL. ANYTHING THAT FALLS THERE WILL ALSO BE
VERY LIGHT.
THE GULF LOW WEAKENS AND DISSIPATES MID-MORNING SATURDAY WITH
LIGHT RAIN SHOWERS PERSISTING ACROSS KODIAK ISLAND. THIS ACTIVITY
TAPERS OFF SATURDAY AFTERNOON TO EVENING. AN INVERTED TROUGH
PIVOTS WESTWARD ACROSS THE GULF SATURDAY EVENING THROUGH SUNDAY
AFTERNOON GIVING COASTAL AREAS AND KODIAK ISLAND ANOTHER CHANCE AT
PRECIPITATION. THE GFS MODEL IS THE MOST BULLISH WITH THIS
SYSTEM. MOST OTHER GUIDANCE WEAKENS THE TROUGH AS IT MOVES
WESTWARD AND KEEPS PRECIPITATION CONFINED TO THE GULF. CONDITIONS
REMAIN RELATIVELY BENIGN AND QUIET SUNDAY AFTERNOON AND INTO THE
NEW WORK WEEK AS THE BERING SEA RIDGE BEGINS TO NUDGE EASTWARD AND
OVER SOUTHCENTRAL.
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3: TONIGHT THROUGH MONDAY)...
THE PRIMARY DRIVING FEATURE FOR SENSIBLE CONDITIONS ACROSS THE
BERING AND SOUTHWEST IS AN ANOMALOUSLY STRONG, BLOCKING HIGH
PRESSURE NOW EXTENDING FROM THE NORTH PACIFIC INTO MUCH OF THE
BERING SEA. THIS RIDGE AXIS WILL CONTINUE TO BUILD IN PLACE OVER
THE WEEKEND AND EXPAND NORTHEASTWARDS WITH TIME, LEADING TO VERY
LITTLE CHANGE IN THE GENERAL PATTERN ALREADY IN PLACE INTO EARLY
NEXT WEEK. IN THE NEAR TERM THROUGH SATURDAY, THE MOST IMPACTFUL
WEATHER WILL BE THE ONGOING STRONG AND GUSTY GAP WINDS ALONG AND
SOUTH OF THE AKPEN AND PARTS OF THE EASTERN ALEUTIANS. GUSTS AS
HIGH AS 60 KTS WERE OBSERVED OVERNIGHT LAST NIGHT INTO THIS
MORNING OUT OF YANTARNI BAY AND KING COVE DUE TO THE FAVORABLE
COMBINATION OF STRONG LOW TO MID LEVEL NORTHERLY FLOW AND COLD AIR
ADVECTION. GUSTS OUT OF FAVORED BAYS AND PASSES IN COULD PICK UP
ONCE AGAIN OVERNIGHT INTO SATURDAY, BUT WILL LIKELY NOT BE QUITE
AS STRONG DUE TO WEAKENING UPPER LEVEL SUPPORT WITH TIME. GAP
WINDS FROM THE EASTERN ALEUTIANS TO AKPEN SHOULD WEAKEN FURTHER
FROM SUNDAY INTO MONDAY AS FLOW AROUND THE STRONG RIDGE TO THE
WEST BECOMES MORE NORTHEASTERLY AND AS COLD AIR ADVECTION CEASES.
LOOKING OUT MORE BROADLY, THE NEXT FEATURE TO WATCH WILL BE A
WEAK SHORTWAVE TROUGH EXPECTED TO ROUND THE TOP OF THE RIDGE
TONIGHT, THEN DRIVE SOUTH INTO PORTIONS OF SOUTHWEST ON SATURDAY.
PARTS OF THE KUSKOKWIM DELTA STILL LOOK ON TRACK TO SEE LIGHT
SNOWFALL AS MOISTURE STREAMS IN FROM THE NORTHWEST AHEAD OF THE
APPROACHING WAVE. AREAS BETWEEN BETHEL AND ANIAK COULD SEE UP TO
AN INCH OF SNOWFALL BEFORE PRECIPITATION MOSTLY SHUTS OFF ON
SATURDAY EVENING. WEAK PERTURBATIONS WILL CONTINUE TO RIDE AROUND
THE RIDGE INTO SOUTHWEST FROM SUNDAY TO MONDAY, SUPPORTING
CONTINUED CHANCES FOR LIGHT SNOW OVER MAINLY HIGHER TERRAIN ALONG
THE KUSKOKWIM MOUNTAINS. AREAS OF FOG, DRIZZLE AND FREEZING
DRIZZLE COULD DEVELOP NEAR THE KUSKOKWIM DELTA COAST AS LOW LEVEL
MOISTURE BUILDS UP UNDER A STRONG SUBSIDENCE INVERSION UNDER THE
STRONG UPPER RIDGE MOVING INTO PLACE. ACROSS MUCH OF THE BERING
SEA AND ALEUTIANS, FOG AND LOW STRATUS WILL BECOME INCREASINGLY
WIDESPREAD THROUGH EARLY NEXT WEEK AS MOISTURE SIMILARLY BUILDS UP
IN THE MARINE LAYER UNDER THE WARMER AIR ALOFT.
-AS
LONG TERM FORECAST (DAYS 4 THROUGH 7: TUESDAY TO FRIDAY)
THE BROAD UPPER LEVEL RIDGE PATTERN ACROSS THE ALASKA REGION
BREAKS DOWN BRIEFLY AS A MODERATE AMPLITUDE TROUGH PASSES FROM
SIBERIA TO THE WESTERN ALASKAN COAST BY THE END OF THE WEEK. THE
UPPER RIDGE HOLDS ON ACROSS THE EASTERN NORTH PACIFIC TO THE
CANADIAN ARCTIC, AND REBUILDS OVER KAMCHATKA BY FRIDAY. A NORTH
PACIFIC UPPER LOW MOVES IN SOUTH OF THE ALASKA PENINSULA THROUGH
FRIDAY. THE GFS / ECMWF / CANADIAN MODEL BLEND THAT CARRIED GOOD
CONTINUITY THROUGH THE FORECAST BEGINS TO DISASSEMBLE, WITH AN
ENSEMBLE MIX PICKING UP THE SLACK AT THE END OF THE FORECAST.
GALE FORCE WINDS WITH POSSIBLE STORM FORCE GUSTS EXITS THE
PACIFIC SIDE OF THE AKPEN FROM THE SHUMAGIN ISLANDS TO KAMISHAK
BAY AND THE BARREN ISLAND THROUGH EARLY WEDNESDAY. A SECOND AREA
OF GALES MOVES OVER THE NORTHERN BERING THROUGH LATE WEDNESDAY.
SNOW SPREADS OVER INTERIOR ALASKA AHEAD OF THE BERING FRONT, AND
EXITS THE STATE EARLY WEDNESDAY. A CENTRAL KAMCHATKA LOW EXTENDS A
FRONT ACROSS THE BERING WITH SNOW INTO THE INTERIOR AND SOUTHWEST
ALASKA, DIMINISHING BY FRIDAY. SNOW CHANGES TO RAIN WITH GUSTY
WINDS AS THE FRONT SLIDES OVER THE ALEUTIANS AND AKPEN THURSDAY. A
WELL DEVELOPED SOUTHERN KAMCHATKA LOW AND FRONT PUSHES LOCALLY
HEAVY RAINS INTO THE WESTERN ALEUTIANS THROUGH FRIDAY.
- KUTZ
.AVIATION...
PANC...VFR CONDITIONS AND LIGHT NORTHERLY WINDS PERSIST THROUGH
SATURDAY MORNING. THERE IS A CHANCE SOME SNOW WILL SPILL OVER THE
MOUNTAINS SATURDAY MORNING, BUT GIVEN THE DRY AIRMASS IN PLACE,
VIRGA IS MORE LIKELY. THIS MAY DROP CEILINGS TO 5000FT.
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