177
FXAK68 PAFC 300220
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
620 PM AKDT WED APR 29 2026
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA
(DAYS 1 THROUGH 3: THIS AFTERNOON THROUGH SATURDAY EVENING)...
DIURNALLY DRIVEN SHOWERS ONCE AGAIN DEVELOPED ACROSS PORTIONS OF
THE MAT-SU VALLEY, KENAI PENINSULA, AND ANCHORAGE. THESE SHOWERS
WILL BEGIN TO TAPER OFF THIS EVENING ONCE DAY-TIME HEATING IS
LOST. GAP WINDS THROUGH TURNAGAIN ARM AND THE KNIK VALLEY WILL
ALSO DIMINISH THIS EVENING AND OVERNIGHT TONIGHT.
THE NEXT WEATHER-MAKER FOR SOUTHCENTRAL IS CURRENTLY GATHERING
SOUTH OF THE ALEUTIAN CHAIN. THIS AREA OF LOW PRESSURE WILL SLIDE
EAST ALONG THE ALASKA PENINSULA AND EVENTUALLY LIFT INTO THE
EASTERN BERING SEA BY THURSDAY AFTERNOON. AT THE SAME TIME, ITS
FRONT WILL LIFT NORTHWARD THROUGH THE GULF ALASKA AND MAKE IT TO
THE NORTH GULF COAST BY FRIDAY MORNING. RAIN WITH MOUNTAIN SNOW
WILL SPREAD FROM SOUTH TO NORTH AND BEGIN FIRST KODIAK ISLAND
THURSDAY MORNING.
DEEP SOUTHERLY TO SOUTHWESTERLY FLOW IN THE MIDDLE TO UPPER-
LEVELS OF THE ATMOSPHERE WILL PROVIDE AMPLE MOISTURE TRANSPORT
FROM THE SUB-TROPICS. A PLETHORA OF SHORTWAVES EMBEDDED IN THE
SOUTHERLY TO SOUTHWESTERLY FLOW WILL ALSO AID IN MODERATE TO HEAVY
RAIN AT SEA-LEVEL WITH HEAVY MOUNTAIN SNOW THURSDAY THROUGH
FRIDAY. PRECIPITATION LINGERS ALONG THE NORTH GULF COAST AND
PRINCE WILLIAM SOUND FOR SATURDAY. ANYWHERE FROM 2 TO 4 INCHES OF
RAIN IS POSSIBLE FROM WHITTIER TO CORDOVA THURSDAY AFTERNOON
THROUGH SATURDAY AFTERNOON WITH THE HIGHER-END TOTALS EXPECTED
ACROSS WHITTIER. 1 TO 2 INCHES OF RAIN IS LIKELY ACROSS KODIAK
ISLAND THURSDAY MORNING THROUGH FRIDAY AFTERNOON. EXPECT DRIER
CONDITIONS WITH SHOWERS FROM TIME TO TIME ACROSS THE WESTERN KENAI
PENINSULA, ANCHORAGE, AND THE MATANUSKA VALLEY DUE TO STRONG
SOUTHEASTERLY DOWNSLOPE FLOW. PORTIONS OF THE WESTERN SUSITNA
VALLEY, PARTICULARLY ALONG THE WESTERN ALASKA RANGE COULD SEE UP
TO 1 TO 2 INCHES OF RAIN DUE TO THE SOUTHEAST FLOW DIRECTION BEING
FAVORABLE FOR UPSLOPE ENHANCEMENT.
THE BIG WILD-CARD IN THE PRECIPITATION FORECAST AS WELL AS THE
PRECIPITATION-TYPE FORECAST WILL BE VALDEZ. WHILE SNOW IS LIKELY
FOR THOMPSON PASS FRIDAY AND INTO SATURDAY, VALDEZ IS ONCE AGAIN
WITHIN A MARGINAL AIRMASS WHEN IT COMES TO COLD AIR. HAVE TRENDED
THE FORECAST SOMEWHAT DIURNALLY WITH RAIN/SNOW MIX DURING THE DAY,
AND SNOW DURING THE EARLY MORNINGS AND NIGHTS FOR FRIDAY THROUGH
SATURDAY.
THE OTHER BIG TICKET ITEM WITH THIS SERIES OF FRONTAL SYSTEMS AND
SHORTWAVES IMPACTING SOUTHCENTRAL THURSDAY THROUGH SATURDAY WILL
BE ANOTHER UPTICK IN GAP WINDS. THIS WILL BE ESPECIALLY TRUE OF
SOUTHEAST WINDS THROUGH TURNAGAIN ARM. THE CORE OF THE STRONGEST
WINDS WILL REMAIN OUT OVER THE ARM ITSELF WHILE SOME SOUTHEAST
WINDS MAKE IT INTO TOWN FOR THURSDAY. FLOW BENDS FURTHER DOWN-
INLET BEGINNING EARLY FRIDAY MORNING WITH A RETURN TO NORTHEAST
WINDS ACROSS THE ANCHORAGE BOWL. HOWEVER, SOUTHEAST WINDS RETURN
ACROSS THE BOWL FRIDAY AFTERNOON AND PERSIST INTO SATURDAY. THE
ANCHORAGE AND EAGLE RIVER HILLSIDE WILL ALSO SEE GUSTY SOUTHEAST
WINDS, POTENTIALLY UP TO 50 MPH THURSDAY NIGHT INTO FRIDAY. THE
KNIK AND COPPER VALLEYS WILL ALSO SEE GUSTY SOUTHEAST WINDS
THURSDAY THROUGH SATURDAY.
ANOTHER SHORTWAVE LIFTS THROUGH THE GULF SATURDAY AFTERNOON AND
EVENING. THIS WILL BRING ANOTHER SHOT OF MOISTURE TO KODIAK
ISLAND, THE NORTHERN GULF COAST, AND PRINCE WILLIAM SOUND. STAY
TUNED FOR MORE FORECAST UPDATES AS THE ACTIVE, WET, AND WINDY
PATTERN UNFOLDS.
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3: TODAY THROUGH SATURDAY)...
SURFACE ANALYSIS SHOWS A DECAYING LOW NEAR SAINT MATTHEW ISLAND WHILE
A NEW, LARGER LOW SITS TO THE SOUTH OF AMCHITKA AND ADAK WITH ITS
ATTENDANT FRONT MOVING ACROSS THE EASTERN ALEUTIANS WITH
RAINFALL. A SHORTWAVE TROUGH DRIVING OVER SOUTHWEST ALASKA IS
KEEPING RAIN/SNOW SHOWERS MOVING ACROSS SOUTHWEST ALASKA FOR THIS
AFTERNOON. WITH A HIGH AMPLITUDE AND PROGRESSIVE PATTERN IN PLACE,
A DIGGING UPPER LEVEL/POSITIVELY TILTED TROUGH WELL SOUTH OF THE
WESTERN ALEUTIANS OVER THE NORTH PACIFIC WILL KEEP THE FIRST LOW
MOVING EASTWARD. OVERNIGHT AND MORNING GUIDANCE HAS TRENDED THIS
LOW JUST A TICK NORTHWARD OF WHAT THE OVERALL THINKING WAS
YESTERDAY, IN WHICH CASE WOULD MOVE THE LOW ACROSS THE ALEUTIAN
CHAIN BETWEEN ADAK AND UNALASKA.
MEANWHILE, THE AFOREMENTIONED FRONT MAKES ITS WAY ACROSS THE
ALASKA PENINSULA AND OVER SOUTHWEST ALASKA THURSDAY MORNING. DUE
TO THE TIMING OF THIS FRONT, THERE WILL LIKELY BE SNOWFALL ON THE
FRONT EDGE OF THIS SYSTEM AS TEMPERATURES ACROSS THE YUKON-
KUSKOKWIM (Y-K) COAST AND DELTA WILL BE HOVERING AROUND THE
FREEZING MARK. THERE LOOKS TO BE A QUICK WINDOW OF LIGHT
ACCUMULATION (DUSTING TO 2 INCHES) BEFORE DAYBREAK FOR THE Y-K
COAST, WITH LESS THAN AN INCH FARTHER INLAND NEAR BETHEL. WITH
CLOUD COVER, ONGOING PRECIPITATION, AND STOUT SOUTHERLY TO
SOUTHEASTERLY WINDS, WARMER AIR WILL QUICKLY WORK INTO THE REGION
AND WARM THE AREA UP INTO THE MID TO UPPER 30S, CHANGING SNOW TO
RAIN. SNOW COULD FALL AS FAR SOUTH AS THE WESTERN CAPES AND
PERHAPS DILLINGHAM, BUT NO ACCUMULATION IS EXPECTED HERE DUE TO A
FAST P-TYPE TRANSITION. MOST OF THE MODEL GUIDANCE HAS SOUTHWEST
ALASKA, ASIDE FROM THE KUSKOKWIM MOUNTAINS, SOLIDLY RAIN HEADING
INTO THE NOON HOUR ON THURSDAY.
A SECONDARY PUSH OF MOISTURE ARRIVES TO SOUTHWEST ALASKA FRIDAY
MORNING AS A SURFACE FRONT AND A LIFTING 500 MB SHORTWAVE MOVES
OVER THE REGION. THE CURRENT THINKING IS THAT THE
WINDWARD/SOUTHERN FACING SLOPES OF THE KUSKOKWIM MOUNTAINS WILL
SEE THE HIGHEST TOTALS (0.4 TO 0.6 INCHES OF QPF) DUE TO UPSLOPE
FORCING THROUGH FRIDAY AFTERNOON. AT THE SAME TIME, AN EASTERLY
FLOW FROM THE FRONT WILL FUNNEL THROUGH KAMISHAK GAP AND POINTS
INLAND. IN SUMMARY, A RAINY/WINDY START OF THE WEEKEND IS IN STORE
FOR THE NORTHERN ALASKA PENINSULA AND SOUTHERN PORTIONS OF
SOUTHWEST ALASKA, WITH LESS RAIN/WIND FARTHER NORTH ACROSS THE
KUSKOKWIM VALLEY.
BEYOND THAT, THE PATTERN STAYS RELATIVELY STEADY STATE THROUGH
THE END OF THE SHORT TERM, WITH MULTIPLE LOWS RIDING SOUTH OF THE
ALEUTIAN CHAIN.
-AM
LONG TERM FORECAST (DAYS 4 THROUGH 7: SUNDAY THROUGH WEDNESDAY)
UPPER LEVEL HIGH PRESSURE OVER THE WESTERN GULF AND LOW PRESSURE
OVER THE EASTERN BERING SEA WILL KEEP SOUTHCENTRAL ALASKA IN AN
ACTIVE STORM TRACK AT THE START OF THE LONG TERM FORECAST PERIOD.
REINFORCING SHORTWAVE TROUGHS AND ASSOCIATED SURFACE FEATURES WILL
SEND A WAVES OF MOISTURE ACROSS SOUTHERN ALASKA SUNDAY THROUGH
TUESDAY. MODEL AGREEMENT REGARDING EXACT TIMING AND PLACEMENT IS
POOR AT THIS TIME, BUT MOST GLOBAL MODELS DEPICT A LOW PRESSURE
SYSTEM MOVING INTO THE WESTERN GULF ON TUESDAY, INCREASING CHANCES
FOR WINDS UP TO GALE-FORCE IN NEARBY WATERS. THINGS GET MESSY
BEYOND THIS, WITH THE ONE THING MODELS AGREEING ON IS LOW PRESSURE
IN THE WESTERN BERING SEA BY WEDNESDAY. THERE ARE HINTS OF HIGH
PRESSURE REDEVELOPING IN THE GULF BY THIS TIME, BUT EXACT
PLACEMENT WILL GREATLY INFLUENCE WEATHER FOR SOUTHCENTRAL. STAY
TUNED AS THINGS BECOME CLEARER IN THE COMING DAYS!
AVIATION
PANC...VFR CONDITIONS WILL PREVAIL. A LOW LEVEL SOUTHWEST SEA
BREEZE IS EXPECTED TO DEVELOP, LIMITING SHOWERS TO MOUNTAINOUS
TERRAIN.
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