909
FXAK68 PAFC 040049
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
449 PM AKDT WED SEP 3 2025
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
DISCUSSION:
LIGHT RAIN SHOWERS CONTINUE ACROSS THE SUSITNA VALLEY THIS
AFTERNOON AS THE FRONT THAT BROUGHT SHOWERS ACROSS SOUTHCENTRAL
THIS MORNING DEPARTS TO THE NORTH. THE FRONT'S PARENT LOW IN THE
EASTERN BERING TRACKS NORTH INTO SOUTHWEST ALASKA THROUGH TONIGHT
AS THE UPPER TROUGH LIFTS AND BEGINS TO SLIDE EAST. THE MAIN
SHIELD OF PRECIPITATION ASSOCIATED WITH SYSTEM IS EXPECTED TO
CONTINUE TO REMAIN OVER SOUTHWEST ALASKA, ALTHOUGH THE NORTHERN
SUSITNA VALLEY WILL ONCE AGAIN SEE THE MOST OUT OF THIS SYSTEM AS
SOUTHERLY 850 MB WINDS WILL AID IN FOCUSING LIFT, AND THUS
PRECIPITATION, ALONG THE HIGHER TERRAIN OF THE ALASKA RANGE.
THE TROUGH LIFTS INTO INTERIOR ALASKA THURSDAY AND SENDS ANOTHER
FRONT AND ROUND OF RAINFALL ACROSS THE REGION BEFORE PUSHING EAST
TOWARDS THE COPPER BASIN ON FRIDAY. HIGH PRESSURE REMAINING OVER
THE GULF AND THE COPPER BASIN AHEAD OF THE APPROACHING TROUGH WILL
HELP TO STRENGTHEN THE PRESSURE GRADIENT OVER THE COASTAL
MOUNTAINS RESULTING IN GUSTY SOUTHERLY WINDS DEVELOPING WEDNESDAY
EVENING THROUGH THURSDAY AFTERNOON IN FAVORED GAPS AND THE COPPER
RIVER VALLEY PRIOR TO THE FRONTAL PASSAGE. THERMAL RIDGING
BUILDING INTO THE COPPER BASIN WILL LIKELY ALLOW FOR TEMPERATURES
TO CLIMB BACK INTO THE MID 70S FOR THURSDAY AFTERNOON. SHOWERS
AGAIN DEVELOP OVER COOK INLET AND THE SUSITNA VALLEY THURSDAY
MORNING BEFORE SHIFTING EAST WITH THE FRONT INTO THE MAT VALLEY,
ANCHORAGE, AND NORTHERN KENAI PENINSULA, BRINGING PERIODS OF
STEADIER RAIN TO THESE AREAS THURSDAY EVENING INTO FRIDAY MORNING.
FOLLOWING THE DEPARTURE OF THIS SYSTEM, BRIEF RIDGING OVER
SOUTHCENTRAL ALASKA WILL ALLOW FOR DRIER CONDITIONS FOR FRIDAY,
BUT WILL BE ACCOMPANIED BY COOLER TEMPERATURES. THE POTENTIAL FOR
RAIN RETURNS AGAIN FOR SATURDAY AS THE ACTIVE PATTERN AND PARADE
OF LOWS IN THE BERING CONTINUES.
.SHORT TERM FORECAST SOUTHWEST ALASKA / BERING SEA / ALEUTIANS
(WEDNESDAY TO SATURDAY)...
A BUSY WEEK FOR SOUTHWEST ALASKA AWAITS AS A LARGE LOW PUSHES IN
FROM THE WEST. THE SMALLER LOW THAT HAS BROUGHT GUSTY WINDS TO
THE EASTERN ALEUTIANS AND ALASKA PENINSULA IS WEAKENING AS IT
MOVES ONSHORE. GUSTY WINDS INCLUDING GAP WINDS ARE DWINDLING AS IT
WEAKENS. THE MAINLAND IS SEEING SCATTERED RAIN SHOWERS AS A FRONT
SWEEPS THROUGH. THESE SHOWERS WILL SLOWLY TAPER OFF THROUGH
THURSDAY AS A RIDGE MOVES IN FROM THE WEST. THIS RIDGE SETS UP IN
THE BERING ON THURSDAY AND ALLOWS FOR CALM WINDS AND LOWER
CHANCES FOR RAIN IN THE EASTERN ALEUTIANS AND PRIBILOF ISLANDS.
THERE MAY BE SOME LOW STRATUS/FOG DUE TO THE STABLE CONDITIONS
THIS RIDGE WILL BRING.
MEANWHILE, THE AFOREMENTIONED LARGE LOW MAKES ITS APPEARANCE IN
THE WESTERN ALEUTIANS ON THURSDAY. HIGH END GALE FORCE WINDS AND
POTENTIALLY SMALL AREAS OF STORM FORCE WINDS WILL IMPACT A SWATH
FROM SHEMYA TO ADAK ISLANDS BY THURSDAY AFTERNOON. HEAVY RAINS
WILL ALSO ACCOMPANY THE LOW. BY FRIDAY MORNING THE LOW'S INITIAL
FRONT WILL PUSH INTO THE EASTERN ALEUTIANS. GALE FORCE WINDS
(HIGHER THROUGH GAP REGIONS) AND HEAVY RAIN ARE EXPECTED IN THE
FOX ISLANDS BY FRIDAY AFTERNOON. THE PRIBILOF ISLANDS WILL ALSO
SEE A PERIOD OF GALE FORCE WINDS AS THE FRONT PASSES. THE STORY
ISN'T OVER FOR THE WESTERN ALEUTIANS AS THE BACK END OF THE LARGE
LOW CROSSES. NORTHERLY WINDS WILL ALLOW FOR COLD AIR ADVECTION,
AIDING IN HIGH WIND SPEEDS THAT WILL ONCE AGAIN BE HIGH END GALE
FORCE WITH THE POTENTIAL FOR SMALL AREAS OF STORM FORCE WINDS.
SATURDAY WILL SEE THE LOW IMPACT ALMOST THE ENTIRE EASTERN BERING
REGION. THE SOUTH END OF THE LOW WILL ALLOW FOR WESTERLY GALE
FORCE WINDS FROM ADAK TO THE FOX ISLANDS. THE SOUTHWEST COAST WILL
SEE SOUTHERLY WINDS, WHICH COULD CAUSE SEA LEVELS TO RISE QUITE A
BIT. IT REMAINS TO BE SEEN IF COASTAL FLOODING WILL BE AN ISSUE,
BUT MONITOR THE FORECAST FOR UPDATES. MODERATE RAINFALL ALSO WILL
AFFECT THE SOUTHWEST MAINLAND AS THE LOW'S FRONTS MOVE INLAND.
GUSTY WINDS THROUGH THE KAMISHAK GAP THROUGH ILIAMNA ARE ALSO
POSSIBLE. LOOKING AHEAD REVEALS ANOTHER POTENTIAL STRONG LOW
MOVING INTO THE BERING SUNDAY OR MONDAY.
-JAR
.LONG TERM FORECAST (DAYS 4 THROUGH 7 - SUNDAY THROUGH
WEDNESDAY)...
A SERIES OF GALE TO STORM-FORCE LOWS TRAVERSE THE BERING SEA
TOWARD MAINLAND ALASKA THIS WEEKEND THROUGH MID-NEXT WEEK. AT THE
BEGINNING OF THE LONG TERM FORECAST ON SUNDAY, THERE IS GOOD
MODEL AGREEMENT ON THE PLACEMENT OF A BROAD, WEAKENING LOW
TRACKING INLAND OVER THE YUKON-KUSKOKWIM DELTA, WITH NORTHWESTERLY
WINDS UP TO GALE FORCE ON THE BACK SIDE OF THE LOW, STREAMING DOWN
ACROSS THE CENTRAL/EASTERN BERING SEA AND ACROSS THE ALASKA
PENINSULA. ASSOCIATED WITH THE LOW, AN AREA OF RAIN SHOWERS
EXTENDS ACROSS SOUTHWEST ALASKA INTO WESTERN PORTIONS OF
SOUTHCENTRAL. THE COPPER RIVER BASIN WILL SEE A CHANCE OF SHOWERS,
BUT IS THE PORTION OF THE MAINLAND WITH THE BEST CHANCE OF
REMAINING DRY THIS WEEKEND.
A RIDGE OVER THE WESTERN/CENTRAL ALEUTIANS KEEPING THE AREA CALMER
AND DRIER QUICKLY SHIFTS EAST AS A STRONGER LOW PRESSURE SYSTEM
IN THE NORTH PACIFIC APPROACHES THE ISLANDS. THERE IS LESS
CONFIDENCE IN THE TRACK AND INTENSITY OF THIS LOW, BUT THERE IS
POTENTIAL FOR THIS LOW TO BRING STORM FORCE WINDS TO PORTIONS OF
THE SOUTHERN AND WESTERN BERING SEA, ALONG WITH THE WESTERN AND
CENTRAL ALEUTIANS LATE SUNDAY INTO MONDAY. THE LOW HAS ORIGINS IN
THE TROPICAL WEST PACIFIC, LIKELY THE EXTRATROPICAL REMNANTS OF A
TROPICAL DEPRESSION CURRENTLY SOUTHWEST OF JAPAN. THIS MEANS
ABUNDANT MOISTURE, WITH PRECIPITABLE WATER VALUES IN EXCESS OF 1.5
INCHES LIKELY LEADS TO MODERATE TO HEAVY RAIN ALONG THE ALEUTIAN
CHAIN AND PORTIONS OF THE ALASKA PENINSULA THROUGH EARLY TUESDAY.
MEANWHILE, SHOWERS LINGER OVER SOUTHCENTRAL ALASKA, SPREADING
POTENTIALLY INTO THE COPPER BASIN ON MONDAY WITH THE UPPER-LEVEL
REMNANT TROUGHING FROM THE SURFACE LOW OPENING INTO A SURFACE
TROUGH OVER WESTERN ALASKA.
HEADING INTO MID-WEEK, THE SECOND BERING SEA LOW SPREADS AMPLE
MOISTURE INTO SOUTHERN MAINLAND ALASKA. CHANCES INCREASE FOR LIGHT
TO MODERATE RAINFALL TUESDAY AND WEDNESDAY. ADDITIONALLY, WITH
THE STRONGER WINDS AND TIDES IN SOME AREAS OF SOUTHWEST ALASKA
REACHING THE HEIGHT OF THEIR CYCLE, THERE IS LOW, BUT NON-ZERO
CONCERN FOR COASTAL FLOODING/EROSION IMPACTS.
QUESADA
AVIATION
PANC...VFR CONDITIONS WILL GENERALLY PREVAIL THROUGH MUCH OF THE
TAF PERIOD. LIGHT WIND EARLY THIS AFTERNOON WILL BECOME STRONGER
AS SOUTHEAST WIND INCREASES OUT OF THE TURNAGAIN ARM. THIS WIND
WILL THEN WEAKEN IN THE MORNING. AS ALWAYS, THERE'S SOME
UNCERTAINTY WITH THE EXACT TIMING OF THE ONSET/END OF THESE
STRONGER WINDS. A TROUGH WILL THEN BRING RAIN INTO THE AREA
THURSDAY AFTERNOON WITH GRADUALLY LOWERING CEILINGS.
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