749
FXAK68 PAFC 162344
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
344 PM AKDT TUE SEP 16 2025
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3:
TONIGHT THROUGH FRIDAY)...
A COMPACT, WELL-DEFINED LOW CENTER IS LOCATED JUST SOUTH OF
SEWARD AS OF 3 PM, BRINGING LIGHT TO MODERATE RAIN SHOWERS ALONG
THE EASTERN KENAI PENINSULA AND PRODUCING A BRIEF BOUT OF GUSTY
NORTHERLY WINDS THROUGH RESURRECTION BAY THIS AFTERNOON. AS THIS
LOW TRACKS ACROSS THE KENAI MOUNTAINS THROUGH THE AFTERNOON AND
INTO THE EARLY EVENING HOURS, STRONG FORCING ALOFT ASSOCIATED WITH
THE FEATURE LIKELY LEADS TO SOME RAIN SHOWERS SPREADING PAST THE
MOUNTAINS. THE BEST CHANCE FOR ACCUMULATING RAINFALL IS OVER THE
WESTERN KENAI PENINSULA, BUT THERE IS A CHANCE FOR SHOWERS AS FAR
NORTH AS ANCHORAGE. THE LOW QUICKLY OPENS INTO A TROUGH AS IT
TRAVERSES THE MOUNTAINS AND PRECIPITATION ASSOCIATED WITH THE LOW
QUICKLY WANES THROUGH MIDNIGHT.
ANOTHER DYNAMICALLY STRONG FEATURE CURRENTLY SOUTHWEST OF HAIDA
GWAII TRACKS INTO THE EASTERN GULF OF ALASKA TONIGHT AND PUSHES
ITS WARM FRONT ACROSS THE CHUGACH MOUNTAINS INTO THE SOUTHERN
COPPER RIVER BASIN. CROSS-BARRIER FLOW WILL BE FAIRLY LIGHT WITH
THIS SYSTEM, MEANING THAT PORTIONS OF THE COPPER BASIN CAN EXPECT
RAINFALL TO SPREAD NORTH LATE ON TUESDAY AND CONTINUE INTO
WEDNESDAY. MODELS HAVE COME INTO BETTER AGREEMENT, LENDING
CONFIDENCE THAT RAIN SPREADS INTO EASTERN PRINCE WILLIAM SOUND
WEDNESDAY MORNING ALONG WITH CENTRAL PORTIONS OF THE COPPER BASIN,
WHILE WESTERN PORTIONS OF THE SOUND LIKELY SEE NO RAIN. THE LOW
QUICKLY WEAKENS ON WEDNESDAY AS IT MOVES INLAND NEAR YAKUTAT,
CAUSING PRECIPITATION TO BECOME SHOWERY AND FOCUS ALONG THE
SOUTHWESTERN SLOPES OF THE COASTAL MOUNTAINS AND THE WRANGELLS.
WEDNESDAY NIGHT AND BEYOND THE FORECAST BECOMES LESS CLEAR WITH
UPPER-LEVEL LONGWAVE TROUGHING SHIFTING EAST FROM THE BERING SEA.
MOIST SOUTHERLY FLOW WITH A SERIES OF WEAK FEATURES EJECTING FROM
THE BASE OF THE TROUGH WILL PROMOTE PERIODS OF RAINFALL OVER THE
GULF WITH UPSLOPE SHOWERS ALONG MUCH OF THE NORTH GULF COAST
THURSDAY AND FRIDAY. WITH A SHIFT TO MUCH WEAKER SHORTWAVES,
CROSS-BARRIER FLOW WILL BE MORE LIMITED THAN PREVIOUSLY
ANTICIPATED, SO PERIODS OF LIGHT RAIN ARE POSSIBLE FOR INLAND
LOCATIONS AS MORE POTENT SHORTWAVES LIFT PAST THE MOUNTAINS.
HOWEVER, RAINFALL ACCUMULATIONS ARE NOT EXPECTED TO BE VERY MUCH.
QUESADA
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3)...
AN UPPER LEVEL LOW LINGERS IN THE EASTERN BERING, WHILE A
WEAKENING SURFACE FRONT CONTINUES EASTWARD ACROSS THE ALASKA
PENINSULA WITH WIND AND RAIN DECREASING THROUGH THIS AFTERNOON.
OCCASIONAL GALE FORCE GUSTS MAY BE POSSIBLE IN OFFSHORE ZONES IN
THE NORTHERN BERING WHILE THE LOW SLOWLY RETROGRADES TO THE WEST
BEFORE DESCENDING INTO THE SOUTHERN BERING ON WEDNESDAY.
ZONAL JET-LEVEL FLOW SOUTH OF THE ALEUTIAN CHAIN WILL FLATTEN AND
ELONGATE THE FRONT EASTWARD ON THURSDAY AS AN UPPER LEVEL
SHORTWAVE IN THE NORTH PACIFIC PHASES WITH THE UPPER LEVEL LOW,
AND DEVELOPS INTO A COMPLEX SYSTEM. MODEL CONSENSUS DEPICTS THE
SYSTEM MOVING ALONG THE ALEUTIAN CHAIN UNDER THE INFLUENCE OF THE
JET, BRINGING RAIN TO THE SOUTHWEST MAINLAND BY THURSDAY
AFTERNOON. GUIDANCE DEPICTS THE LOW DEVELOPING INTO A NEGATIVELY
TILTED OPEN TROUGH OVER THE EASTERN BERING BY FRIDAY MORNING.
.LONG TERM FORECAST (DAYS 4 THROUGH 7: SATURDAY THROUGH
TUESDAY)...
WEST-TO-EAST ZONAL FLOW OVER THE MAJORITY OF THE REGION WILL
MAINTAIN THE UNSETTLED WEATHER PATTERN, HOWEVER DIMINISH THE
LIKELIHOOD FOR HIGHLY IMPACTFUL WEATHER PATTERNS. MODELS HAVE BEEN
STRUGGLING COMING TO A CONSENSUS ON TIMING THE FINER DETAILS OF
FEATURES AND SHORTWAVES PUSHING THROUGH THE REGION, PARTICULARLY
GIVEN THE ZONAL FLOW. CONFIDENCE HOWEVER IS STRONG THAT BY
SATURDAY MORNING, A LOW PRESSURE SYSTEM WILL BECOME ESTABLISHED
OVER THE NORTHERN GULF OF ALASKA, BRINGING THE POTENTIAL FOR HEAVY
RAIN AND STRONG WINDS TO THE SOUTHCENTRAL COAST. DEPENDING ON THE
LOW'S ORIENTATION, THERE IS THE CHANCE FOR A BARRIER JET TO FORM
ALONG THE MARINE AREAS OF THE NORTHERN GULF COAST FRIDAY INTO
SATURDAY. THROUGH THE WEEKEND, RAIN IS EXPECTED TO CONTINUE ALONG
THE GULF COAST AND INTO SOUTHWEST ALASKA. AREAS OF GUSTY WINDS
THROUGH THE SOUTHERN GAPS AND PASSES OF THE ALASKA PENINSULA AND
EASTERN ALEUTIANS THAT WEEKEND AS WELL, GIVEN THE PERSISTENT
NORTHWESTERLY FLOW IN THE AREA. IN ADDITION, SOUTHWESTERLY UPPER
LEVEL FLOW WILL BRING THE POTENTIAL FOR RAIN TO MOVE UP COOK INLET
AND INTO THE MAT-SU VALLEYS. BY TUESDAY MORNING, AGREEMENT IS
GENERALLY FAIR THAT A TROUGH WILL REMAIN OVER THE SOUTHCENTRAL
AREA, WITH A RIDGE OVER THE ALEUTIANS. HOWEVER, BY TUESDAY MORNING
SOME SOLUTIONS ARE ADVERTISING A NEW TROUGH TO APPROACH THE
WESTERN PERIPHERY OF THE RIDGE MUCH MORE RAPIDLY THAN OTHERS. THIS
WILL LEAD TO LOWER FORECAST CONFIDENCE CURRENTLY FOR EARLY NEXT
WEEK.
-CL
AVIATION
PANC...VFR CONDITIONS WITH LIGHT AND VARIABLE WINDS WILL PERSIST
THROUGH THE TAF PERIOD. A FEW SHOWERS COULD MOVE OVER THE TERMINAL
THIS LATE THIS AFTERNOON THROUGH LATE THIS EVENING; HOWEVER,
CEILINGS SHOULD REMAIN ABOVE 5,000 FEET.
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