469
FXAK68 PAFC 140338
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
738 PM AKDT SUN SEP 13 2026
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3: TODAY
THROUGH TUESDAY)...
WITH A BROAD RIDGE OVER THE GULF OF ALASKA, RELATIVELY DRIER AND
CALMER CONDITIONS ARE EXPECTED THROUGH TODAY AND MONDAY. SIMILARLY
TO THIS MORNING, MONDAY MORNING WILL LIKELY SEE ANOTHER ROUND OF
FOG ACROSS COASTAL LOCATIONS INCLUDING HOMER, KENAI, CORDOVA,
ANCHORAGE, AND POTENTIALLY PALMER IN THE MORNING HOURS, LIFTING BY
THE LATE MORNING. THE PATTERN IS POISED TO SHIFT STARKLY TO
SIGNIFICANTLY MORE WET AND WINDY BY TUESDAY.
MOST OF THE DAY ON MONDAY WILL REMAIN ON THE DRY SIDE, BUT MID TO
UPPER LEVEL CLOUDS WILL REALLY START TO SPREAD IN AS A WARM FRONT
STEMMING FROM A DEVELOPING LOW OUT WEST LIFTS INTO THE KENAI
PENINSULA. LIGHT RAIN CHANCES ALONG THE FRONT WILL STEADILY
INCREASE BY THE AFTERNOON HOURS, FIRST ACROSS THE KENAI PENINSULA,
THEN SHIFTING NORTH INTO ANCHORAGE AND THE MAT-SU BY MONDAY
EVENING. RAIN WILL BEGIN TO SPREAD INTO THE COPPER BASIN AS THE
FRONT CONTINUES TO LIFT NORTH THROUGH MONDAY NIGHT, BUT MAY
STRUGGLE TO REACH THE GROUND AT LOWER ELEVATIONS IN THE VICINITY
OF GLENNALLEN.
BY TUESDAY, STRONG SOUTH TO SOUTHWEST FLOW WILL REALLY BEGIN TO
RAMP UP AS THE BERING LOW OUT WEST INTENSIFIES AS IT REACHES THE
COAST NEAR THE YUKON-KUSKOKWIM DELTA. VERY STRONG AND GUSTY
SOUTHERLY GAP WINDS WILL BEGIN BY TUESDAY MORNING AND THEN
INTENSIFY THROUGHOUT THE DAY AS THE LOW STARTS TO LIFT INTO THE
WESTERN INTERIOR AND HELPS TO TIGHTEN UP A SHARP SOUTHEAST TO
NORTHWEST PRESSURE GRADIENT ACROSS SOUTHCENTRAL. GUSTS OUT OF THE
TURNAGAIN ARM, KNIK AND COPPER VALLEYS COULD BECOME QUITE INTENSE,
PERHAPS REACHING AS MUCH AS 30 TO 50 MPH (AND LOCALLY HIGHER ALONG
THE HILLSIDE AND TURNAGAIN ARM) BY THE AFTERNOON HOURS ON TUESDAY.
SOUTHERLY DOWNSLOPE FLOW CLOSE TO THE SURFACE MAY ALSO BE ENOUGH
TO DRY THINGS OUT IN THE LEE OF THE MOUNTAINS TEMPORARILY ON
TUESDAY MORNING, BUT EXPECT RAIN TO FILL BACK IN JUST ABOUT
EVERYWHERE ALONG AND WEST OF THE CHUGACH MOUNTAINS AND KENAI
PENINSULA BY THE AFTERNOON. PRECIPITATION AND WINDS ARE EXPECTED
TO DECREASE AFTER THE FRONT PASSES TUESDAY NIGHT, LEAVING
WEDNESDAY RELATIVELY CALMER WITH WEAKER WINDS AND DRIER
CONDITIONS.
-CL/AS
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3: SUNDAY MORNING THROUGH WEDNESDAY AFTERNOON)...
KEY MESSAGES: A HIGH SURF ADVISORY IS IN EFFECT FROM 1PM MONDAY
TO 10PM TUESDAY FOR THE KUSKOKWIM DELTA COAST.
*KWIGILLINGOK, KONGIGANAK, AND KIPNUK: WATER LEVELS AS HIGH AS
1.0 TO 2.5 FEET ABOVE THE NORMAL HIGHEST TIDE LINE. SOUTHWEST
WINDS 25 TO 35 MPH WITH GUSTS TO 40 TO 45 MPH BEFORE WINDS
TRANSITION TO WEST TUESDAY MORNING, DIMINISHING IMPACTS.
*TOKSOOK BAY AND TUNUNAK: WEST WINDS 30 TO 40 MPH WITH GUSTS TO
45 TO 50 MPH BEGINNING TUESDAY MORNING. WATER LEVELS AS HIGH AS
0.5 TO 1.5 FEET ABOVE THE NORMAL HIGHEST TIDE LINE.
DISCUSSION:
AS OF THIS AFTERNOON, A FRONT LIFTING ACROSS THE BRISTOL BAY
REGION IS PRODUCING WIDESPREAD RAIN SHOWERS AND AREAS OF DENSE
FOG. WITH A STRONG HIGH POSITIONED TO THE SOUTHEAST ACROSS THE
NORTH PACIFIC, MOISTURE TRANSPORT AND STRONG WINDS ARE BEING
REDIRECTED AROUND THE WESTERN PERIPHERY OF THE HIGH AND WILL SOON
BEGIN TO EMERGE NORTHWARD OUT OF THE NORTH PACIFIC MONDAY MORNING.
WITH THAT, A DEVELOPING LOW PRESSURE SYSTEM IS STILL ON TRACK TO
ENTER THE BERING BY MONDAY MORNING. FROM HERE, MODELS HAVE BEEN
TRENDING TOWARDS A STRONGER SOLUTION WITH THIS LOW AS IT CLOSES IN
ON THE KUSKOKWIM DELTA COAST MONDAY AFTERNOON, BUT RUN-TO-RUN
CONSISTENCY HAS BEEN RELATIVELY POOR. SOME REASONING BEHIND THIS
IS THAT ALOFT, AT 500 MB, A DIGGING AND DEEPENING LONGWAVE TROUGH
TO THE WEST HAS A SERIES OF SEVERAL SHORTWAVES ROUNDING THE BASE
OF THE LONGWAVE, AND THERE IS STILL SOME UNCERTAINTY ON HOW WELL
THESE INDIVIDUAL FEATURES PHASE AND CONSOLIDATE. IF THESE UPPER
LEVEL WAVES LAG BEHIND ONE ANOTHER, THE SYSTEM WILL BE ON THE
WEAKER SIDE, BUT IN THE EVENT OF TRUE PHASING MATERIALIZING, WE
ARE LOOKING AT A STRONGER STORM. ALL SAID, THE GENERAL CONSENSUS
IS THAT A LENGTHY FETCH OF STRONG 25 TO 30 KNOT SOUTH TO SOUTHWEST
WINDS DEVELOP AND REACH THE KUSKOKWIM DELTA COAST BY EARLY MONDAY
AFTERNOON. WITH A SOUTHEAST WIND DIRECTION, WINDS ARE ON TRACK TO
INCREASE TO SUSTAINED GALES BY EARLY MONDAY AFTERNOON/EVENING
WITH GUSTS UP TO 50 KNOTS. SHOULD THIS SYSTEM TREND STRONGER, COLD
BAY COULD BE TICKING UP TO THE NEIGHBORHOOD OF HIGH WIND
CRITERIA, BUT FORECASTER CONFIDENCE ON WIND GUSTS REACHING HIGHER
THAN STORM FORCE IS LOW AS OF THIS TIME (10 TO 20 PERCENT).
CONDITIONS ALONG THE KUSKOKWIM DELTA COAST WILL BEGIN TO
DETERIORATE EARLY MONDAY AFTERNOON WITH ROUGH SEAS AND HIGH SURF
MAKING IT TO THE COASTLINE. WITH THIS PUSH OF ONSHORE WINDS, GUSTS
ARE LIKELY TO TOP OUT IN THE 40 TO 45 MPH RANGE HEADING INTO
TUESDAY MORNING. COINCIDING WITH HIGH TIDE, WATER LEVELS ARE
EXPECTED TO REACH AS HIGH AS 2.5 FEET ABOVE THE NORMAL HIGH TIDE
LINE. AS THE LOW PRESSURE SYSTEM MOVES INLAND LATER TUESDAY
MORNING, SOUTHWEST WINDS WILL SHUT OFF AND GUSTY WESTERLY WINDS
WILL BEGIN AFFECTING TOKSOOK BAY AND TUNUNAK. THESE WINDS ARE
GENERALLY ON TRACK TO BE A TICK STRONGER (MOSTLY DUE TO THE GAP
WIND EFFECT BETWEEN NUNIVAK ISLAND AND TOKSOOK BAY). HOWEVER, THE
FETCH WILL NOT BE AS LONG, WHICH WILL LIMIT COASTAL IMPACTS.
STILL, TOKSOOK BAY AND TUNUNAK ARE EXPECTED TO SEE WIND GUSTS FROM
45 TO 50 MPH LATE TUESDAY MORNING TO EARLY TUESDAY AFTERNOON AND
WATER LEVELS UP TO 1.5 FEET ABOVE THE NORMAL HIGH TIDE LINE. DUE
TO THE FACT THAT ALMOST ALL OF THE MODELS SHOW THE LOW TRENDING
STRONGER ON ITS APPROACH TO THE KUSKOKWIM DELTA COAST, WE WILL
CONTINUE TO CLOSELY MONITOR THIS SYSTEM AND FINE TUNE THE FORECAST
AS WE DRAW CLOSER TO THE EVENT. WHAT IS INTERESTING WITH THIS
STORM IS THAT SOME OF THE MORE RECENT RUNS OF THE GLOBAL MODELS
SHOW MORE CONFIDENCE IN UPPER LEVEL PHASING AS THE LOW MOVES
ONSHORE, WHICH IN RETURN WOULD DEEPEN THE LOW EVEN AS IT TRACKS
INLAND. THIS IS RELATIVELY UNCOMMON TO SEE, BUT POSSIBLE IF THE
UPPER LEVEL FORCING IS THERE. STAY TUNED.
-AM
LONG TERM FORECAST (THURSDAY THROUGH SUNDAY)
A MORE FALL-LIKE PATTERN IS ON THE WAY FOR THE REGION. BUT FIRST,
A SHORTWAVE RIDGE OVER EASTERN ALASKA WILL HOLD ON TO SOME OF THE
LAST FEW CRUMBS OF SUMMER FOR SOUTHCENTRAL ON THURSDAY.
MEANWHILE, TROUGHING WILL GENERATE CLOUDS WITH SHOWERS FOR THE
ALASKA PENINSULA AND SOUTHWEST. THIS TROUGH WILL MOVE EASTWARD ON
FRIDAY, PUSHING THE RIDGE AWAY, BRINGING CLOUDS AND SHOWERS TO
SOUTHCENTRAL THROUGH SATURDAY.
AN UPPER LEVEL KAMCHATKA LOW WILL ENTER THE BERING EARLY FRIDAY
AND FORM A LOW AT THE WESTERN END OF THE ALEUTIANS. THERE IS MODEL
AGREEMENT BETWEEN THE GFS AND EURO WHERE IT WILL TRACK EAST AND
CROSS INTO THE GULF BY SATURDAY. THIS LOW WOULD BRING RAIN AND
WIND FOR SOUTHCENTRAL, SOUTHWEST, AND ALASKA PENINSULA THIS
WEEKEND. THERE IS LARGE VARIANCE IN THE MODELS TRACKING THE PATH
OF THE LOW IN THE GULF, HOWEVER THERE IS AGREEMENT UPON LESS OF A
FETCH AREA FEEDING TROPICAL MOISTURE INTO THE SYSTEM. HENCE, WILL
BE MORE OF A NUISANCE WITH MINIMAL IMPACTS.
-SS
AVIATION
PANC...VFR CONDITIONS AND LIGHT WINDS UNDER FEW TO SCT CLOUDS
CONTINUE THROUGH THIS EVENING. LIFR FOG AND LOW STRATUS MOVE BACK
INTO THE AIRPORT / WEST ANCHORAGE MONDAY MORNING AROUND 12Z.
AB
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