856
FXAK68 PAFC 050033
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
433 PM AKDT WED JUN 4 2025
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3:
TONIGHT THROUGH SATURDAY)...
THE SUNNIEST AND DRIEST PART OF SOUTHCENTRAL THIS AFTERNOON IS
KODIAK ISLAND AS A LOW CENTERED NEAR THE BARREN ISLANDS PUSHES ITS
FRONT INTO THE SOUTHCENTRAL MAINLAND. LIGHT TO MODERATE RAINFALL
IS ONGOING ACROSS MUCH OF THE AREA, WITH THE EXCEPTION OF THE
COPPER BASIN, WHICH REMAINS DRY AND STRONGLY DOWNSLOPED. AFTER THE
INITIAL ARRIVAL OF UPPER-LEVEL FORCING WITH THE FRONT THIS
MORNING, MODERATE DOWNSLOPING HAS TAKEN OVER AND IS KEEPING
PRECIPITATION LIGHT AND INTERMITTENT FOR THE INTERIOR KENAI
PENINSULA, ANCHORAGE, AND THE MATANUSKA VALLEY. PRECIPITATION IS
STILL ON TRACK TO INTENSIFY FOR THESE AREAS TONIGHT AS THE UPPER-
LEVEL TROUGH AXIS PIVOTS EAST AND SOUTHEASTERLY FLOW ALOFT WEAKENS
AND BECOMES WESTERLY. SIMILARLY, EXPECTING RAIN SHOWERS TO SPREAD
INTO THE COPPER BASIN OVERNIGHT AND INTO THURSDAY. SOUTHEASTERLY
GAP WINDS CONTINUE THIS AFTERNOON/EVENING, THOUGH WEAKER THAN THE
PAST SEVERAL DAYS. WINDS DIMINISH TONIGHT AS THE LOW TRACKS INTO
PRINCE WILLIAM SOUND, ERODING THE COASTAL RIDGE. SOUTHERLY WINDS
MAY CONTINUE IN THE COPPER RIVER BASIN ON THURSDAY, HOWEVER, AS
TROUGHING PERSISTS OVER THE INTERIOR.
MOVING INTO THURSDAY AFTERNOON FLOW WILL BECOME MORE ZONAL,
ALLOWING FOR A A SLIGHT DRYING TREND AS WESTERLY FLOW OFF THE
ALASKA AND ALEUTIAN RANGES DRIES THINGS OUT SLIGHTLY. KODIAK
ISLAND AND THE WESTERN KENAI, AND EVEN POSSIBLY ANCHORAGE MAY SEE
SOME SUNSHINE ON THURSDAY. SURFACE HEATING FROM THE SUN COULD LEAD
TO SOME VIGOROUS SHOWER DEVELOPMENT FOR THE SUSITNA VALLEY AND AS
A RESULT THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS DURING THE
AFTERNOON/EVENING. FOR FRIDAY, WEAK RIDGING ALOFT TRIES TO BUILD
IN, CONTINUING A TREND OF GRADUAL WARMING AND DRYING. FRIDAY
BRINGS THE MOST PLEASANT CONDITIONS OF THE FORECAST PERIOD, THOUGH
ANOTHER NORTH PACIFIC LOW TRACKS INTO THE SOUTHERN GULF, BUILDING
A COASTAL RIDGE WHICH ALLOWS SOUTHERLY GAP WINDS TO RETURN. THESE
WEAKEN FOR SATURDAY AS THE LOW IN THE GULF SPREADS ITS FRONT NORTH
ACROSS SOUTHCENTRAL, BRINGING ANOTHER WET DAY FOR THE START OF THE
WEEKEND.
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(DAYS 1 THROUGH 3: TODAY THROUGH FRIDAY)...
WEAK LOWS CONTINUE TO MOVE THROUGH THE SW MAINLAND THE NEXT 48
HOURS. RIDGING CONTINUES TO BUILD IN FOR THE ALEUTIANS THROUGH
THE END OF THIS WEEK.
LOW-LEVEL CLOUDS AND SCATTERED RAIN SHOWERS CONTINUED TODAY IN THE
SW MAINLAND THOUGH AMOUNTS THOUGH 4:00 PM TODAY RANGED FROM A
HUNDREDTH TO A TENTH OF AN INCH. THIS COOLER AIR, ITS RESULTANT
INSTABILITY AND CLEARING SKY IN THE ANIAK TO SLEETMUTE AREA THIS
AFTERNOON AND EVENING CONTINUE THE 10% CHANCE OF AN ISOLATED
THUNDERSTORM. FARTHER WEST, THE NORTHWESTERLY TO NORTHERLY WINDS
KEPT THE SW ALASKA COASTLINE IN FOG/MIST/LOW CEILINGS THROUGH THIS
AFTERNOON. THIS TREND CONTINUES OVERNIGHT AS PERSISTENT ONSHORE
FLOW ALLOWS A SATURATED MARINE LAYER TO REMAIN IN PLACE. NORTHERLY
FLOW WILL TURN NORTHWESTERLY THIS EVENING IN THE ALEUTIANS AND AK
PEN RESULTING IN DECREASED GAP WIND GUSTS.
AHEAD OF THE BUILDING RIDGE, A WEAK LOW MOVES THROUGH THE BERING
SEA EAST OF THE PRIBILOF ISLANDS THEN INTO BRISTOL BAY THIS
EVENING/OVERNIGHT. IT WILL CAUSE CONTINUED LOW CEILINGS AND A MIX
OF RAIN/SNOW SHOWERS LATE THIS EVENING INTO LATE TOMORROW MORNING.
A BRING A BRIEF PERIOD OF HIGHER WAVE HEIGHTS TO THE BRISTOL BAY
SHORELINE FROM PORT HEIDEN TO EGEGIK LATE THIS EVENING ARE
EXPECTED THOUGH THE SATURATED MARINE LAYER'S LOW CLOUDS WILL KEEP
THE HIGHEST WINDS FROM MIXING DOWN AND CREATING GALE-FORCE WINDS.
ELSEWHERE IN THE ALEUTIANS, FOG IS EXPECTED TONIGHT AND TOMORROW
WITH THE APPROACHING RIDGE BUILDING.
LONG TERM FORECAST (DAYS 4 THROUGH 7: SUNDAY THROUGH WEDNESDAY)
ON THE ALASKA WEATHER MAP, THE PERSISTENT UPPER LEVEL TROUGH
RELAXES THROUGH THE FORECAST PERIOD, BECOMING A MEDIUM AMPLITUDE
SET OF WAVES. THE CLOSED LOW CENTERS OVER WESTERN ALASKA WEAKEN AS
THE TROUGH MOVES INTO EASTERN ALASKA THROUGH TUESDAY, CONTINUING
INTO WESTERN CANADA FOR WEDNESDAY. FORECAST CONFIDENCE IS GOOD
USING GFS / ECMWF AND CANADIAN MODELS.
A DECAYING SURFACE LOW MOVES ALONG THE NORTH GULF COAST,
SPREADING MODERATE TO HEAVY RAIN FROM THE EASTERN KENAI TO THE
CANADIAN BORDER FOR SUNDAY. LIGHTER RAIN EXTENDS TO THE ALASKA
RANGE FROM THIS LOW. IN THE WEST, A WELL DEVELOPED SURFACE LOW AND
FRONT APPROACHES THE WESTERN ALEUTIANS SUNDAY NIGHT AND SPREADS
LOCALLY MODERATE RAIN ACROSS THE ALEUTIANS AND SOUTHERN BERING TO
THE ALASKA PENINSULA BY MIDWEEK.
- KUTZ
AVIATION
PANC...EXPECT VFR CEILINGS AND VIS TO PREVAIL THROUGH THIS
EVENING AS SOUTHEASTERLY FLOW ALOFT HELPS KEEP THE BULK OF ANY
LOWER CLOUDS AND PRECIPITATION AWAY FROM THE TERMINAL. HOWEVER,
CLOUDS ARE EXPECTED TO LOWER WITH RAIN RETURNING AFTER 3Z AS AN
AREA OF LOW PRESSURE MOVES UP COOK INLET AND WEAKENS, ALLOWING FOR
THE DOWNSLOPING WINDS ALOFT TO DIMINISH. RAIN AND MVFR CIGS AND
VIS ARE EXPECTED TO PERSIST FROM LATE THIS EVENING THROUGH
THURSDAY MORNING. BY MID-MORNING, WINDS ALOFT WILL BECOME MORE
WESTERLY, HELPING TO DRIVE ANY LINGERING MOISTURE AND CHANCES FOR
SHOWERS EAST OF THE TERMINAL AND ACROSS THE FOOTHILLS OF THE
CHUGACH MOUNTAINS.
A SOUTHEASTERLY TURNAGAIN ARM WIND IS EXPECTED TO REDEVELOP OVER
THE TERMINAL BY EARLY AFTERNOON. HOWEVER, THIS SOUTHEASTERLY WIND
MAY NOT BE CONSISTENT AS THE WINDS COMING OUT OF TURNAGAIN ARM
WILL LIKELY FAN BOTH UP AND DOWN INLET DUE TO COMPETING PRESSURE
GRADIENTS FROM THE LOW TO THE SOUTH AND A TROUGH ALONG THE LEE OF
THE ALASKA RANGE. ANY SOUTHEASTERLY WIND OVER THE TERMINAL THIS
AFTERNOON AND EVENING WILL LIKELY BE GUSTY AT TIMES, OVER 20 KTS.
A LIGHTER SOUTH WIND WILL CONTINUE LATE TONIGHT THROUGH THURSDAY
MORNING BEFORE A GUSTY SSE WIND RETURNS FOR THURSDAY AFTERNOON.
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