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FXAK68 PAFC 101258
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
458 AM AKDT WED JUN 10 2026
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3: TODAY
THROUGH FRIDAY)...
AN UPPER LEVEL SHORTWAVE TROUGH HAS NEARLY STALLED OUT OVER THE
WESTERN HALF OF SOUTHCENTRAL THIS MORNING. TO THE EAST, A DECAYING
COLD FRONT IS CONTINUING TO LOSE DEFINITION AS IT HEADS INTO THE
COPPER VALLEY AND DOWN INTO THE CENTRAL GULF OF ALASKA. SKIES
REMAIN MOSTLY CLEARED OUT ACROSS THE COOK INLET AND SUSITNA
VALLEY, BUT LINGERING SHOWERS AND RELATED CLOUD DEBRIS IS
PERSISTING ACROSS MUCH OF THE MOUNTAIN RANGES ACROSS THE REGION
AND OVER THE COPPER VALLEY. WIDELY SCATTERED SHOWER ACTIVITY IS
PERSISTING IN A FEW SPOTS AS WELL, MAINLY OVER MOUNTAINOUS
TERRAIN.
THINGS ARE LOOKING ON TRACK FOR A COUPLE MORE ACTIVE DAYS IN TERMS
OF SHOWER AND THUNDERSTORM POTENTIAL ACROSS A GOOD PORTION OF
SOUTHCENTRAL. A SECONDARY UPPER SHORTWAVE TROUGH WILL DIG DOWN
FROM THE WESTERN INTERIOR THIS AFTERNOON, THEN WILL SLOWLY MERGE
WITH THE INITIAL TROUGH OVER THE PRINCE WILLIAM SOUND AND COPPER
VALLEY DURING THE DAY ON THURSDAY. THIS WILL KEEP PLENTY OF COLD
AIR ALOFT IN PLACE ALONG WITH WEAK SYNOPTIC LIFT AHEAD OF EACH
SHORTWAVE TROUGH, COMBINING WITH DAYTIME HEATING TO SUPPORT A
DECENT AMOUNT OF INSTABILITY AND STEEP LOW TO MID-LEVEL LAPSE
RATES DURING THE AFTERNOON AND EVENING HOURS BOTH TODAY AND
TOMORROW. SHOWERS AND THUNDERSTORMS WILL SPRING UP NEAR AND ACROSS
THE CHUGACH, KENAI AND TALKEETNA MOUNTAINS TODAY, AS WELL AS MUCH
OF THE MAT-SU AND COPPER VALLEYS. THE BEST CHANCE TO SEE LIGHTNING
WILL BE CONCENTRATED ACROSS THE NORTHERN COPPER VALLEY, WHERE
INSTABILITY AND LIFT AHEAD OF THE TROUGH WILL BE MOST PRONOUNCED.
THUNDERSTORMS WILL AGAIN BE MOST LIKELY ACROSS THE NORTHERN
COPPER VALLEY ON THURSDAY AS THE SECONDARY TROUGH STALLS OUT
OVERHEAD.
SHOWER AND THUNDERSTORM POTENTIAL WILL CONTINUE TO SHIFT NORTH FOR
FRIDAY AS THE TROUGH IN PLACE BEGINS TO WEAKEN AND DRIFT
NORTHWARDS WITH TIME. MUCH OF THE NORTHERN ALASKA RANGE AND
NORTHERN COPPER VALLEY WILL HAVE THE BEST CHANCE TO SEE LIGHTNING.
MEANWHILE, A STRONG FRONTAL BOUNDARY AND DEEP MOISTURE TAP WILL
BEGIN TO LIFT NORTH INTO THE GULF BY FRIDAY EVENING. THIS SYSTEM
WILL HAVE THE POTENTIAL TO PRODUCE SIGNIFICANT RAINFALL ACROSS
PORTIONS OF SOUTHCENTRAL LATER THIS WEEKEND.
-AS
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(DAYS 1 THROUGH 3: TODAY THROUGH FRIDAY AFTERNOON)...
A PATTERN OF PERSISTENCE OVER SOUTHWEST ALASKA AND THE BERING
WILL MAKE FOR A REPETITIVE WEATHER REGIME THROUGH THE REMAINDER OF
THE WEEK ACROSS THE REGION. TEMPERATURES IN THE SOUTHWEST
INTERIOR HAVE BEEN WARMER THAN PREVIOUSLY EXPECTED, AND WITH
CONTINUED CLEAR SKIES, THE WARMER TREND WILL PERSIST. HOWEVER,
ALONG THE COAST AND OVER THE VAST MAJORITY OF THE BERING SEA,
RIDGING HAS SETTLED OVER THE AREA ALLOWING FOR A VERY LARGE SWATH
OF LOW STRATUS CLOUDS AND FOG OVER THE AREA. THE LOWEST CEILINGS
AND FOG WILL BE MOST PROMINENT IN THE OVERNIGHT AND EARLY MORNING
HOURS, LIFTING TO A LOW STRATUS IN THE AFTERNOONS. FOG AND LOW
STRATUS BEHAVIOR IS HIGHLY DEPENDENT ON SMALLER-SCALE DYNAMICS
THAT ARE DIFFICULT FOR WEATHER MODELS TO REPRESENT, WHICH MAKES
THE FINER DETAILS OF THE FOG FORECAST CHALLENGING, SUCH AS PRECISE
TIMING AND DENSITY OF THE FOG.
GIVEN THE AMPLE SURFACE HEATING OVER THE SOUTHWEST ALASKA
INTERIOR, CONVECTIVE ACTIVITY IS EXPECTED IN SOME CAPACITY
BEGINNING THURSDAY AFTERNOON AND CONTINUING THE FOLLOWING
AFTERNOONS. ONE CRITERIA WE WILL CONTINUE TO WATCH THE NEXT FEW
DAYS IS UPPER-LEVEL SUPPORT FOR THESE POTENTIAL SYSTEMS. AREAS
WITH MORE SUPPORT MAY SEE AN INCREASED AMOUNT OR NUMBER OF
CONVECTIVE CELLS OR THUNDERSTORMS. OVERALL, THE UPPER LEVEL
FORCING FOR THESE TWO DAYS LOOKS FAIRLY WEAK AND CHAOTIC, WHICH
SUGGESTS THUNDERSTORM DEVELOPMENT WILL LIKELY BE ISOLATED AND
PRODUCE RELATIVELY INFREQUENT LIGHTNING ACTIVITY.
A NEW LOW PRESSURE SYSTEM IS POISED TO APPROACH THE SOUTHERN
ALASKA PENINSULA BY FRIDAY AFTERNOON. THIS SYSTEM'S RAINFALL AND
MOVEMENT IN THE OVERALL AIR COLUMN MAY BRING A REPRIEVE IN THE FOG
OVER THE AREA, BUT REPLACE IT WITH CONTINUED LOW STRATUS AND LIGHT
RAIN. EASTERLY GALE-FORCE WINDS ARE EXPECTED TO ESTABLISH OVER THE
SOUTHERN SIDE OF THE PENINSULA, INCLUDING FOR COMMUNITIES SUCH AS
SAND POINT, PERSISTING INTO SATURDAY MORNING.
-CL
.LONG TERM FORECAST (DAYS 4 THROUGH 7: SATURDAY THROUGH
TUESDAY)...
AN UPPER LEVEL RIDGE OVER THE EASTERN GULF WILL REMAIN NEARLY
STATIONARY THROUGH SUNDAY AND THEN MOVE EASTWARD BY MONDAY. THIS
IS IMPORTANT AS IT BLOCKS AN ORIGINATING PACIFIC LOW FROM GOING
INTO THE EASTERN GULF, WHICH WILL BRING SHOWERS FOR SOUTHWEST
ALASKA AND THE EASTERN ALEUTIANS THROUGH TUESDAY. THE COMBINATION
OF THE ANTICYCLONIC FLOW ALOFT FROM THE RIDGE AND CYCLONIC FLOW
FROM THE LOW PRESSURE SYSTEM WILL ENHANCE SOUTHERLY FLOW USHERING
IN WARM AND MOIST AIR INTO THE NORTHERN AND WESTERN GULF COAST.
THIS IS EXPECTED TO BRING PRECIPITATION TO SOUTHCENTRAL ALASKA,
THE ALASKA PENINSULA, AND KODIAK ISLAND. THERE IS HIGH CONFIDENCE
THAT THERE WILL BE PERIODS OF HEAVY RAIN FOR KODIAK ISLAND THROUGH PRINCE
WILLIAM SOUND SATURDAY INTO SUNDAY. LINGERING SHOWERS ARE POSSIBLE
MONDAY THROUGH TUESDAY AS THE SOUTHERLY ENHANCED FLOW SHUTS OFF.
FORECAST CONFIDENCE IS LOW FOR THE WESTERN ALEUTIANS.
-SS
AVIATION
PANC...VFR CONDITIONS WILL PREVAIL THROUGHOUT THE TAF PERIOD.
IT'S LIKELY SOUTHEAST WINDS BLOWING OUT OF THE TURNAGAIN ARM WILL
RETURN SOMETIME THIS EVENING, BUT DON'T EXPECT WIND GUSTS MUCH
ABOVE 20 KTS AT THE TERMINAL. SHOWERS AND ISOLATED THUNDERSTORMS
WILL DEVELOP THIS AFTERNOON, BUT THERE IS A VERY HIGH CHANCE THIS
ACTIVITY WILL STAY CONFINED TO THE MOUNTAINS.
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