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FXAK68 PAFC 120032
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
432 PM AKDT MON AUG 11 2025
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
HIGH PRESSURE IS BUILDING ACROSS SOUTHCENTRAL AS THE REMNANTS OF
SHOWERS LARGELY CONTAINED TO THE COPPER RIVER BASIN AND
SURROUNDING MOUNTAINS EASE AND DRIFT EASTWARD OUT OF THE REGION.
DRIER CONDITIONS WILL PERSIST THE REMAINDER OF TONIGHT, TUESDAY,
AND THE EARLY PORTION OF WEDNESDAY. TEMPERATURES WILL BE NEAR
NORMAL TODAY THEN WARMING TOMORROW AS THERMAL RIDGE BUILDS OVER
SOUTHCENTRAL. THE COPPER BASIN WILL SEE A DROP IN RELATIVE
HUMIDITY VALUES, BUT LIGHT WINDS WILL NEGATE THE BULK OF ANY FIRE
WEATHER CONCERNS. BY MIDWEEK, A SERIES OF TROUGHS WILL BRING
COOLER TEMPERATURES AND INCREASED CHANCES FOR SHOWERS TO THE
REGION TO CLOSE OUT THE WEEK. AGREEMENT BETWEEN MODEL SOLUTIONS IS
CURRENTLY POOR AS TO THE ARRIVAL OF THE SHORTWAVES INCOMING TO
SOUTHCENTRAL. THIS DEGRADES CONFIDENCE TOWARDS THE PRECISE TIMING
ON THE PATTERN SHIFT FOR THE REGION, HOWEVER BY WEDNESDAY EVENING,
MUCH OF SOUTHCENTRAL BESIDES THE COPPER RIVER BASIN WILL RETURN
TO A COOLER, CLOUDIER, AND RAINIER PATTERN. AGREEMENT IS HIGH
HOWEVER REGARDING THE PASSAGE OF THE WAVES OVER KODIAK ISLAND,
WITH LIGHT RAIN BEGINNING EARLY WEDNESDAY MORNING, AND DIMINISHING
BY WEDNESDAY EVENING.
-CL
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3/TONIGHT THROUGH THURSDAY)...
A LONG-WAVE TROUGH IS CENTERED OVER THE BERING SEA, WITH RIDGING
DOWNSTREAM OVER SOUTHERN ALASKA. A SUBTROPICAL JET STREAK IS
ORIENTED WEST-EAST ALONG THE ALEUTIAN CHAIN. THE CIMSS MIMIC
LAYER PRECIPITABLE WATER PRODUCT SHOWS EXTREMELY JUICY AIR JUST
SOUTH OF THE ALEUTIANS, WITH PRECIPITABLE WATER VALUES IN EXCESS
OF 2". SOME OF THE MOISTURE IS FEEDING INTO THE FRONT SIDE OF THE
BERING TROUGH, WITH TPW VALUES IN EXCESS OF 1". ZOOMING IN ON THE
BERING SEA, THERE ARE NUMEROUS SHORT-WAVES TROUGHS EMBEDDED WITHIN
THE LONG-WAVE TROUGH, CREATING SOME COMPLEXITIES (AND RESULTANT
UNCERTAINTY) IN THE SHORT-TERM FORECAST. THE STRONGEST OF THE
SHORT-WAVES IS OVER THE NORTH-CENTRAL BERING SEA, ANCHORED BY A
LARGE BUT FAIRLY WEAK LOW CENTER. A WEAKER SHORT-WAVE AND SURFACE
LOW ARE LOCATED BETWEEN ADAK AND DUTCH HARBOR. INTERACTION OF THE
TWO STORM SYSTEMS HAS LED TO A SINGLE NORTH-SOUTH ORIENTED FRONTAL
BOUNDARY OVER THE CENTRAL BERING AND ALEUTIANS. STRONG AND GUTSY
SOUTHERLY WINDS ALONG WITH RAIN ARE FOCUSED AHEAD OF THIS
BOUNDARY. ALL OF THIS IS PROGRESSING SLOWLY EASTWARD. THE UPPER
LEVEL RIDGING IS PROVIDING PARTLY TO MOSTLY SUNNY SKIES OVER MUCH
OF SOUTHWEST AK TODAY, THOUGH RAIN AND WIND ARE ARRIVING ALONG THE
KUSKOKWIM DELTA COAST. A HIGH SURF ADVISORY REMAINS IN EFFECT
THROUGH 10PM TUESDAY FOR THE KUSKOKWIM DELTA COAST FOR WATER
LEVELS AT OR A LITTLE ABOVE THE NORMAL HIGHEST TIDE LINE. FORECAST
WATER LEVELS HAVE LOOKED LESS AND LESS IMPRESSIVE DUE TO CHANGES
IN THE EVOLUTION OF LARGE SCALE WEATHER FEATURES, BUT HAVE DECIDED
TO KEEP THE ADVISORY IN PLACE.
THE FORECAST IS LARGELY ON TRACK FOR THE NEXT COUPLE DAYS AS RAIN
AND WIND SLOWLY SPREAD EASTWARD TO SOUTHWEST ALASKA. MODEL
SOLUTIONS DO VARY IN THE TRACK OF SPECIFIC UPPER LEVEL SHORT-
WAVES, LEADING TO DIFFERENCES IN TIMING OF RAIN OVER SOUTHWEST AK.
REGARDLESS, ALL OF SOUTHWEST CAN EXPECT TO A SEE A PERIOD OF LIGHT
RAIN SOMETIME TUESDAY NIGHT OR WEDNESDAY. STRONG GUSTY GAP WINDS
WILL BE FOUND OUT AHEAD OF THE FRONT FROM NIKOLSKI AND
UNALASKA/DUTCH HARBOR TO THE SOUTHERN ALASKA PENINSULA. THE UPPER
TROUGH WILL EXIT EASTWARD THURSDAY, BRINGING AN END TO STEADY RAIN
OVER SOUTHWEST AK, THOUGH HIGH PRESSURE AND ONSHORE FLOW FROM THE
BERING WILL LIKELY MAINTAIN CLOUDS AND COOL TEMPERATURES -
ESPECIALLY ALONG THE COAST.
THE LARGEST CHANGE TO THE FORECAST IS WEDNESDAY THROUGH WEDNESDAY
NIGHT. A LOW TRACKING ALONG THE SUBTROPICAL JET IN THE NORTH
PACIFIC HAS SHIFTED SIGNIFICANTLY FURTHER NORTH IN THE LATEST
MODEL GUIDANCE. THUS, EXPECT RAIN AND WIND (SMALL CRAFT ADVISORY
LEVEL) TO AFFECT THE ALEUTIANS CHAIN AS THE LOW TRACKS THROUGH.
HIGH PRESSURE WILL DOMINATE THE ENTIRE REGION BY THURSDAY ,LEADING
TO QUIET CONDITIONS AND LIKELY REDEVELOPMENT OF LOW CLOUDS AND
FOG.
-SEB
LONG TERM FORECAST (DAYS 4 THROUGH 7: FRIDAY THROUGH MONDAY)
BY FRIDAY, UPPER LEVEL TROUGHING WILL STRETCH ACROSS THE CENTRAL
AND EASTERN TWO THIRDS OF THE STATE FROM THE ARCTIC TO THE
SOUTHEAST PANHANDLE. HIGH PRESSURE RIDGING WILL CONTINUE TO BUILD
OVER THE ALEUTIANS AND SOUTHWEST ALASKA, LIKELY PLAGUING THE
BERING SEA WITH SOME FOG AND LOW STRATUS. THE TIGHTENING PRESSURE
GRADIENT OVER THE ALASKA PENINSULA WILL PRODUCE GUSTY NORTHERLY
GAP WINDS THROUGH FAVORABLE BAYS AND AND PASSES FRIDAY AND
SATURDAY.
RAIN SHOWERS MAY LINGER ACROSS SOUTHCENTRAL ON FRIDAY AS A
SHORTWAVE MOVES ACROSS THE STATE AND GETS PULLED INTO THE GULF. A
DRYING TREND IS EXPECTED TO COMMENCE WITH GENERALLY QUIET WEATHER
THROUGH THE WEEKEND. A TROUGH MOVING OVER THE ALEUTIAN CHAIN THIS
WEEKEND COULD BRING SHOWERS AND ENHANCED WINDS, BUT THIS FEATURE
LOOKS PROGRESSIVE AND MOVE THROUGH QUICKLY. OVERALL, LOOK FORWARD
TO A GENERALLY SETTLED WEATHER PATTERN ACROSS SOUTHERN ALASKA.
AVIATION
PANC...VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD.
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