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FXAK68 PAFC 011309
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
509 AM AKDT TUE JUL 1 2025
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3: TODAY
THROUGH THURSDAY)...
AS WAS MENTIONED YESTERDAY, SOUTHCENTRAL ALASKA REMAINS IN A COL
BETWEEN UPPER LEVEL RIDGING TO THE NORTHEAST AND SOUTHWEST, AND
UPPER LEVEL LOWS TO THE WEST AND SOUTHEAST. THE LOW TO THE WEST IS
THE ONE THAT IS SENDING A FRONT TOWARD KODIAK AND IS BRINGING
SOME RAIN FROM KAMISHAK BAY TO KODIAK EARLY THIS MORNING. THIS
FRONT WILL STALL OUT TODAY AS THE LOW DIGS TO THE SOUTHEAST AND
UNDERCUTS THE WEAK RIDGE THAT IS TRYING TO BUILD INTO SOUTHCENTRAL
FROM THE NORTH. THE RESULT WILL BE RAIN FOR KODIAK ISLAND TODAY
INTO WEDNESDAY NIGHT. THE CLEARING OVER THE COPPER RIVER BASIN
EARLY THIS MORNING SHOULD EXPAND TO THE SOUTHWEST TODAY AND
OVERCOME THE CLOUDS MOVING IN FROM THE WEST OVER COOK INLET AND
THE SUSITNA VALLEY. THESE MID AND HIGHER LEVEL CLOUDS ARE
ASSOCIATED WITH THAT LOW TO THE WEST WHILE THE LOWER LEVEL CLOUDS
PERSISTING OVER ANCHORAGE AND ALONG THE WESTERN SLOPES OF THE
TALKEETNA, CHUGACH AND KENAI MOUNTAINS ARE DUE TO THE PERSISTENT
MARINE LAYER THAT HAS INVADED THE COOK INLET REGION THE PAST FEW
DAYS. THIS SHIFT IN PATTERN SHOULD ALLOW THE ANCHORAGE AREA AND
OTHER AREAS NEAR COOK INLET TO FINALLY CLEAR OUT THE CLOUDS TO A
BETTER DEGREE ARE THE SYNOPTIC FLOW WILL FINALLY TURN TO MORE
DOWN-INLET AND ADVECT THAT MARINE AIRMASS AWAY FROM THE AREA. IN
ADDITION, TURNAGAIN ARM WINDS ARE EXPECTED TO DEVELOP OVER
ANCHORAGE THE NEXT TWO AFTERNOONS AND EVENINGS WHICH WILL ALSO
BRING IN A MODIFIED AIRMASS TO LOWER LEVELS WHICH SHOULD ONLY HELP
THE SITUATION.
WHILE SOME SUNNY BREAKS ARE EXPECTED OVER THE REGION TODAY INTO
THURSDAY, IT WILL LIKELY NOT BE A COMPLETE CLEARING OUT OF THE
CLOUDS AS A SHORT WAVE IS EXPECTED TO MOVE INTO THE COPPER RIVER
BASIN ON WEDNESDAY AND THEN TOWARD THE COOK INLET REGION FOR
THURSDAY. THERE WILL BE CLOUDS ASSOCIATED WITH THIS SHORTWAVE AND
RAIN IS LIKELY IN THE EASTERN COPPER BASIN AS IT MOVES THROUGH.
WITH IT REACHING THAT AREA IN THE EARLY MORNING HOURS ON
WEDNESDAY, IT IS LESS LIKELY TO INITIATE THUNDERSTORMS WITH IT AS
IT GOES THOUGH. HOWEVER, AFTER IT PASSES THROUGH THE AREA, THE
ATMOSPHERE WILL LIKELY BE UNSTABLE ENOUGH FOR SOME THUNDERSTORMS
WEDNESDAY AFTERNOON AND EVENING. ONE OF THE BIGGEST FORECAST
QUESTIONS THIS MORNING IS HOW FAR WESTWARD THE RAIN WILL PROGRESS
ON THURSDAY.
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3: TODAY THROUGH THURSDAY MORNING)...
A MATURE LOW PRESSURE SYSTEM OVER THE ALASKA'S WEST COAST
CONTINUES TO BRING GUSTY SOUTHERLY WINDS AND MODERATE TO HEAVY
RAIN TO THE REGION TODAY. ABUNDANT TROPICAL MOISTURE BEING DRAWN
NORTH ACROSS THE ALASKA PENINSULA WILL DELIVER A SWATH OF RAIN
FROM TOGIAK TO KING SALMON, UP THROUGH ANIAK AND SLEETMUTE.
ADDITIONAL RAIN AMOUNTS BETWEEN 0.6 AND 1.5 INCHES ARE EXPECTED
THROUGH THIS AFTERNOON, WITH THE HEAVIEST TOTALS EXPECTED FROM
DILLINGHAM TO THE NORTH. THIS SYSTEM WILL SLOWLY DRIFT SOUTH
TODAY BEFORE A TRIPLE POINT LOW FORMS SOUTH OF THE AKPEN WEDNESDAY
MORNING, WHICH WILL TAPER OFF PRECIPITATION BY WEDNESDAY
AFTERNOON.
MEANWHILE, FOR THE REST OF THE BERING SEA, A RIDGE WILL BUILD
BEHIND THE LOW, BRINGING QUIETER WEATHER ACROSS THE WESTERN AND
CENTRAL ALEUTIANS TOMORROW EVENING. THE EASTERN ALEUTIANS WILL
CONTINUE TO CONTEND WITH NORTHERLY FLOW AND RAIN SHOWERS
DOWNSTREAM OF THE RIDGE THROUGH WEDNESDAY MORNING. AREAS OF FOG
ARE LIKELY TO REDEVELOP FOR THE WESTERN BERING AND ALEUTIANS,
BENEATH THE RIDGE, BEFORE THE FRONT OF A NEW LOW OUT OF KAMCHATKA
SWEEPS ACROSS THE WESTERN BERING THURSDAY MORNING.
LONG TERM FORECAST (DAYS 4 THROUGH 7: FRIDAY THROUGH MONDAY)
STARTING OFF THE LONG TERM IS THE PRESENCE OF AN UPPER HIGH IN
NORTHERN ALASKA. THIS, COMBINED WITH AN UPPER LOW IN THE GULF OF
ALASKA WILL ALLOW EASTERLY FLOW INTO INLAND AREAS OF
SOUTHCENTRAL. THIS FLOW WILL ALLOW FOR CHANCES FOR SHOWERS AND
THUNDERSTORMS IN THE COPPER RIVER BASIN, AND THE TALKEETNA
MOUNTAINS FOR THE 4TH OF JULY. EASTERLY STORM MOTION MAY ALLOW
SOME OF THESE SHOWERS AND THUNDERSTORMS TO STREAM INTO THE SUSITNA
VALLEY. SOUTHWEST ALASKA WILL HAVE A LARGE LOW IN THE BERING
SLOWLY MAKE ITS WAY EASTWARD. HEAVY RAINFALL WILL IMPACT THE
EASTERN ALEUTIANS AND ALASKA PENINSULA WITH THE MAINLAND COAST
SEEING RAIN BY SATURDAY. THE LOW WILL STALL OUT JUST OFF THE
KUSKOKWIM DELTA COAST AND WILL CONTINUE TO SEND FRONTS EASTWARD,
BRINGING HEAVY RAIN TO THE SOUTHWEST MAINLAND FOR THE REST OF THE
WEEKEND AND INTO MONDAY.
SOUTHCENTRAL WILL SEE SOME RIDGING BUILD IN ON SATURDAY. THIS
WILL RESULT IN A DRYING AND WARMING TREND FOR THE REGION. THE
COPPER RIVER BASIN, TALKEETNA MOUNTAINS, AND THE SUSITNA VALLEY
WILL RETAIN CHANCES FOR THUNDERSTORMS DESPITE THE RIDGE. THIS
DRYING TREND WILL NOT LAST TOO LONG AS A FRONT FROM THE LOW IN
THE BERING WILL ARRIVE ON SATURDAY. HEAVY RAINFALL IS EXPECTED
FIRST IN KODIAK ON SATURDAY AFTERNOON, THEN AT THE SOUTHCENTRAL
COASTLINE. ANCHORAGE AND THE MAT-SU VALLEY MAY RECEIVE RAINFALL
FROM THIS FRONT AS WELL IF IT ORIENTS CORRECTLY. THIS SCENARIO IS
UNCERTAIN AS MODEL AGREEMENT IS QUITE POOR AT THIS MOMENT.
ADDITIONAL WEAKER FRONTS PUSH INTO THE GULF INTO MONDAY WITH THE
POTENTIAL FOR SCATTERED RAINFALL.
-JAR
.AVIATION...
PANC...MVFR CEILING SHOULD SLOWLY LIFT THROUGH THE MORNING HOURS
WITH VFR CONDITIONS REMAINING AFTER THAT. THE SOUTHEASTERLY
TURNAGAIN ARM WINDS ARE EXPECTED TO DEVELOP THIS AFTERNOON AND
PERSIST INTO THE OVERNIGHT HOURS BEFORE SETTLING DOWN SOME. THESE
WINDS ALONG WITH A CHANGE IN THE PATTERN OVER THE REGION SHOULD
HELP PREVENT THE LOW LEVEL CLOUDS FROM DEVELOPING AGAIN.
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