091
FXAK68 PAFC 060022
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
422 PM AKDT FRI SEP 5 2025
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
A BRIEF BREAK FROM MORE ACTIVE WEATHER IS EXPECTED THIS EVENING
ACROSS SOUTHCENTRAL, WITH BREAKS OF SUN BEGINNING TO SHOW IN MANY
LOCATIONS. A FRONT NEAR THE ALCAN BORDER EXITS EAST INTO YUKON
THIS EVENING, WITH COOLER AIR ALOFT PROVIDING JUST ENOUGH
INSTABILITY FOR SOME ISOLATED THUNDERSTORMS IN PORTIONS OF THE
COPPER BASIN, WHERE A FEW LIGHTNING STRIKES HAVE ALREADY BEEN
OBSERVED TODAY. BEHIND THE FRONT, A RIDGE TRANSITING ACROSS
SOUTHCENTRAL IS BRINGING INCREASINGLY CALM AND SUNNY/CLEAR
CONDITIONS.
TONIGHT, CHANCES FOR RAIN RETURN AS A LARGE BERING SEA LOW
EXTENDS A FRONT INTO SOUTHERN MAINLAND ALASKA. A LEADING
SHORTWAVE TROUGH MAY BE JUST ENOUGH TO PROMOTE SOME LIGHT RAIN
SHOWERS FOR THE ANCHORAGE BOWL AND MATANUSKA VALLEY LATE TONIGHT
INTO SATURDAY MORNING AS MID-LEVEL MOISTURE BEGINS TO STREAM IN ON
SOUTHWESTERLY FLOW. LOW-LEVEL FLOW BEGINS TO INTENSIFY OUT OF THE
SOUTH TO SOUTHEAST ON SATURDAY, LEADING TO SOME DOWNSLOPING WHICH
LIMITS PRECIPITATION AMOUNTS IN THE LEE OF THE COASTAL MOUNTAIN
RANGES. A COASTAL RIDGE ALSO BEGINS TO DEVELOP AS A SURFACE FRONT
OFF THE BERING LOW SLOWLY PUSHES INTO THE WESTERN GULF. THIS WILL
INITIATE TYPICAL SOUTHEASTERLY GAP WINDS, INCLUDING THE TURNAGAIN
ARM, KNIK, AND COPPER RIVER WINDS BY THE AFTERNOON. EXPECT LIGHT,
INTERMITTENT RAIN FOR INLAND LOCATIONS, WHILE 1 TO 2 INCHES OF
RAIN IS SQUEEZED OUT ALONG THE NORTH GULF COAST THROUGH MONDAY.
AS THE MAIN SURFACE FRONT LIFTS ACROSS SOUTHCENTRAL ON SUNDAY,
WEAKENING CROSS-BARRIER FLOW MAY LIMIT DOWNSLOPING AND ALLOW FOR
A MORE SUSTAINED PERIOD OF LIGHT RAINFALL FOR INLAND AREAS. THE
SURFACE LOW OPENS INTO A TROUGH SUNDAY NIGHT AND SHIFTS INTO
SOUTHCENTRAL ALASKA AND THE GULF FOR MONDAY, KEEPING THE POTENTIAL
FOR LIGHT RAIN SHOWERS ONGOING AREA-WIDE. DECREASING PRESSURE IN
THE GULF OF ALASKA ERODES THE COASTAL RIDGE, HOWEVER, LEADING TO
FAIRLY CALM WINDS FOR THE BEGINNING OF NEXT WEEK.
QUESADA
.SHORT TERM FORECAST SOUTHWEST ALASKA / BERING SEA / ALEUTIANS
(TODAY THROUGH MONDAY)...
CURRENTLY THIS AFTERNOON, A LARGE LOW IS CENTERED NORTH OF ADAK.
IT'S FRONT HAS REACHED THE EASTERN ALEUTIANS, PRIBILOF ISLANDS,
AND ALMOST TO COASTAL SOUTHWEST ALASKA. GUSTY GALE FORCE WINDS
AND MODERATE TO HEAVY RAINFALL ARE AFFECTING COMMUNITIES IN THE
AFOREMENTIONED REGIONS. GUSTS THROUGH GAP REGIONS ARE STRONGER AND
MAY REACH STORM FORCE IN STRENGTH THROUGH SATURDAY. MEANWHILE,
THE BACK END OF THE LOW IS BRINGING ANOTHER ROUND OF GALE FORCE
WINDS TO THE WESTERN ALEUTIANS. ONE EFFECT OF THIS LARGE LOW IS
WESTERLY GALE FORCE WINDS AS THE SOUTH SIDE OF THE LOW ROLLS
ALONG THE ALEUTIAN ISLANDS. THESE WESTERLY WINDS WILL REACH THE
EASTERN ALEUTIANS BY SATURDAY AFTERNOON, BUT THEY WILL BE SMALL
CRAFT BY THEN BECAUSE THE LOW WILL BE WEAKENING.
BACK TO THE KUSKOKWIM COAST, WATER LEVELS WILL RISE AS SOUTH-
SOUTHEASTERLY WINDS INCREASE IN STRENGTH THROUGH EARLY SATURDAY.
THEY WILL REACH GALE FORCE BY SATURDAY MORNING. SIGNIFICANT
COASTAL FLOODING IS NOT EXPECTED, BUT LOW-LYING AREAS FILLING UP
AND INCREASED WAVES/SURF ALONG THE COAST ARE NOT OUT OF THE
QUESTION, ESPECIALLY AROUND KWIGILLINGOK AND KIPNUK. A SPECIAL
WEATHER STATEMENT IS CURRENTLY OUT FOR THE KUSKOKWIM DELTA
COAST/NORTHERN KUSKOKWIM BAY COAST WITH MORE DETAILS ABOUT
WIND SPEEDS, WAVE HEIGHTS AND IMPACTS.
BY SATURDAY AFTERNOON, THE LOW WILL HAVE WEAKENED AND WINDS WILL
DECREASE TO SMALL CRAFT ALONG THE SOUTHWEST COASTLINE AND THE
ALEUTIAN ISLANDS. RAINFALL WILL BECOME LIGHTER AND MORE SCATTERED
AS THE LOW PUSHES INTO THE MAINLAND. ONE LAST PUSH OF NORTHERLY
SMALL CRAFT WINDS WILL AFFECT THE PRIBILOF ISLANDS AND THE EASTERN
ALEUTIANS/ALASKA PENINSULA REGIONS BEFORE THE LOW DISSIPATES ON
SUNDAY. RAIN SHOWERS WILL CONTINUE IN THE SOUTHWEST MAINLAND AS
THE REMNANT UPPER TROUGH PASSES ON SUNDAY. MEANWHILE, THE BERING
WILL SEE A RIDGE OF HIGH PRESSURE MOVE IN SUNDAY. THIS MEANS
LIGHTER WINDS AS WELL AS LOWER CHANCES FOR RAINFALL. PERIODS OF
CLEAR SKIES ARE ALSO POSSIBLE WITH THE RIDGE. THE RIDGE WILL
FLATTEN OUT ON MONDAY AS YET ANOTHER LOW MOVES IN FROM THE
SOUTHWEST. THERE IS BETTER MODEL AGREEMENT ON THIS LOW FROM
YESTERDAY AND A SOUTHERLY AND WEAKER SOLUTION HAS WON OUT. THIS
MEANS THAT LOWER IMPACTS CAN BE EXPECTED FROM THIS LOW. STILL,
GALE FORCE WINDS AND MODERATE TO HEAVY RAINFALL WILL BE LIKELY IN
THE CENTRAL ALEUTIANS. THERE IS STILL UNCERTAINTY ABOUT THE
EASTERN ALEUTIANS/ALASKA PENINSULA REGIONS, SO MONITOR THE
FORECAST FOR UPDATES.
-JAR
.LONG TERM FORECAST (DAYS 4 THROUGH 7 - TUESDAY THROUGH
FRIDAY)...
ONLY MINOR CHANGES FROM PREVIOUS DISCUSSION... AT THE BEGINNING
OF THE WEEK, A GALE OR POTENTIALLY STORM-FORCE LOW IS LIKELY TO BE
LOCATED NEAR THE CENTRAL ALEUTIANS. TO THE EAST, A TROUGH EXTENDS
SOUTH ACROSS WESTERN ALASKA INTO THE GULF OF ALASKA. NEAR AND
AHEAD OF THE TROUGH AXIS, RAIN SHOWERS WILL BE FAVORED AS A FORMER
SURFACE LOW PRESSURE SYSTEM WINDS DOWN AND DEPOSITS ITS MOISTURE
ACROSS THE STATE. THE TROUGH EXITS EAST INTO YUKON BY TUESDAY,
WITH A QUICKLY- PROGRESSING RIDGE MOVING IN TO REPLACE IT ACROSS
SOUTHERN MAINLAND ALASKA. AS A RESULT, RAIN SHOWERS DIMINISH
ACROSS THE REGION. ALONG THE ALEUTIANS, IT IS DIFFICULT TO
PINPOINT IMPACTS FROM THE POTENTIALLY STORM-FORCE LOW, AS THERE IS
SIGNIFICANT UNCERTAINTY IN THE TRACK. REGARDLESS, EXPECT PERIODS
OF STRONG, GUSTY WINDS, POTENTIALLY AS STRONG AS STORM FORCE.
ACCOMPANYING THE LOW WILL ALSO BE TROPICAL MOISTURE WITH
PRECIPITABLE WATER VALUES OF 1.5 INCHES OR GREATER SOURCED FROM
TROPICAL STORM PEIPAH (CURRENTLY LOCATED OVER SOUTHWESTERN JAPAN)
AND STRONG DYNAMICS WHICH WILL LEAD TO MODERATE TO HEAVY RAIN
ALONG THE ALEUTIANS ON MONDAY.
FOR TUESDAY, THE LOW TRACKS NEAR OR JUST SOUTH OF THE ALEUTIANS
TOWARD THE ALASKA PENINSULA AND INTO THE NORTHERN GULF OF ALASKA.
THE OCCLUDING LOW BEGINS TO LOSE SOME OF ITS MOISTURE TAP AND
STRENGTH, THOUGH ITS FRONT, DEPENDING ON TRACK, MAY LIFT INTO THE
SOUTHWEST ALASKA COAST NEAR GALE FORCE. THIS WOULD LEAD TO A LOW
POTENTIAL FOR SOME COASTAL FLOODING/EROSION CONCERNS ON TUESDAY,
THOUGH A MORE SOUTHERN TRACK WOULD NEGATE THIS POTENTIAL. LIGHT TO
MODERATE RAINFALL BEGINS TO MOVE INLAND OVER PARTS OF SOUTHWEST
ALASKA, REGARDLESS OF TRACK. IN GENERAL, THE LOW APPEARS STRONGER
THAN THE PREVIOUS LOW, SO WINDS AND PRECIPITATION ARE EXPECTED TO
BE GREATER THAN WHAT IS SEEN ON FRIDAY AND SATURDAY.
THE LOW TRACKS SOMEWHERE IN THE VICINITY OF KODIAK ISLAND BY
WEDNESDAY. ITS FRONT PUSHES EAST ALONG THE GULF OF ALASKA COAST,
WHERE IT MAY CAUSE MODERATE TO HEAVY RAIN ALONG THE COASTAL
MOUNTAINS. THE ABUNDANT MOISTURE AND WEAK TO MODERATE CROSS-
BARRIER FLOW LIKELY ALLOWS FOR AT LEAST SOME RAINFALL TO PUSH PAST
THE COASTAL MOUNTAINS INTO INLAND SOUTHCENTRAL AT TIMES. THE LOW
CONTINUES TO SHIFT SLOWLY EASTWARD TOWARD THE END OF THE WEEK,
KEEPING GENERALLY SHOWERY CONDITIONS IN PLACE ACROSS THE SOUTHERN
MAINLAND, WITH HEAVIER RAIN ALONG THE COAST. FOR THE BERING SEA
AND ALEUTIANS, SURFACE HIGH PRESSURE MOVES IN MID-WEEK, THOUGH THE
UPPER-LEVEL PATTERN APPEARS FAIRLY MESSY AND THE CONFIDENCE IN
ANY INDIVIDUAL FEATURE'S LOCATION IS VERY LOW.
QUESADA/DD
AVIATION
PANC...VFR CONDITIONS AND LIGHT WINDS WILL PERSIST THROUGH THE
EVENING HOURS. OVERNIGHT INTO SATURDAY MORNING A WEAK DISTURBANCE
AND FRONT ALOFT WILL BRING A PERIOD OF LIGHT RAIN AND POTENTIALLY
LOWER CEILINGS IN THE MARGINAL VFR RANGE. IF THESE DEVELOP, EXPECT
THEM TO LIFT BY LATE MORNING OR EARLY AFTERNOON SATURDAY AS A
LIGHT TURNAGAIN ARM WIND DEVELOPS.
MTL
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