249
FXAK68 PAFC 090107
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
507 PM AKDT FRI AUG 8 2025
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
SHORTWAVES CONTINUE TO MOVE THROUGH SOUTHCENTRAL AS AN ARCTIC
TROUGH DIPS INTO WESTERN ALASKA. THESE WAVES ARE BRINGING
SCATTERED RAINFALL ACROSS SOUTHCENTRAL INCLUDING ANCHORAGE. RAIN
CHANCES WILL SLOWLY TAPER OFF INTO THE EVENING IN ANCHORAGE AND
THE MAT-SU VALLEY. THERE IS A CHANCE THAT A TURNAGAIN WIND WILL
BEND INTO THE WESTERN ANCHORAGE AREA AS A COASTAL RIDGE FORMS ON
THE CHUGACH MOUNTAINS. RAIN SHOWERS WILL TAPER OFF IN THE
ANCHORAGE AND NORTHERN KENAI REGIONS IN THE EVENING, BUT STEADY
RAINFALL WILL REMAIN IN THE COASTAL REGIONS AND NEAR THE ALASKA
RANGE.
BY SATURDAY MORNING, A LOW RIDING ON TOP OF A RIDGE WILL PASS
THROUGH THE GULF OF ALASKA, THIS LOW WILL SHOVE A GOOD AMOUNT OF
MOISTURE INTO SOUTHCENTRAL. WINDS ALOFT WILL BECOME LIGHTER IN THE
ANCHORAGE AND MAT-SU VALLEY REGIONS BY THE AFTERNOON HOURS. THIS
MEANS THAT STEADY RAINFALL IS LIKELY ONCE THIS OCCURS. INSTABILITY
WILL BE PRESENT IN THE SUSITNA VALLEY FROM TALKEETNA TO SKWENTNA,
SO THUNDERSTORMS ARE POSSIBLE BEFORE THE MAIN BULK OF RAINFALL
ARRIVES IN THE EVENING HOURS. THE COPPER RIVER BASIN WILL BE DRIER
WITH PERIOD OF SUNSHINE. AS THE LOW PASSES BY, GAP WINDS AROUND
KODIAK ISLAND AND ANOTHER TURNAGAIN WIND IN ANCHORAGE WILL CROP
UP ONCE AGAIN. WINDS ARE EXPECTED TO REACH SMALL CRAFT STRENGTH IN
THE BARREN ISLANDS AND SHELIKOF STRAIT.
AS THE ARCTIC LOW MOVES NORTH OF THE REGION ON SUNDAY, RAINFALL
WILL LINGER IN THE TALKEETNA MOUNTAINS AND THE COPPER RIVER
BASIN. ANCHORAGE AND THE MAT-SU VALLEY WILL SEE THEIR UPPER LEVEL
FLOW TURN SOUTHWESTERLY, SO RAINFALL MAY CONTINUE ON IN THOSE
LOCATIONS UNTIL THE NIGHTTIME HOURS. THE COPPER RIVER BASIN NORTH
OF GULKANA AND THE SUSITNA VALLEY NORTH OF TALKEETNA WILL HAVE
A CHANCE OF THUNDERSTORMS BEFORE THOSE REGIONS DRY OUT. A RIDGE
BUILDS IN ON MONDAY, DRYING OUT MUCH OF SOUTHCENTRAL APART FROM
THE EASTERN MOST REGIONS OF THE COPPER RIVER BASIN.
-JAR
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3)...
AN UPPER LEVEL ARCTIC TROUGH CUTTING SOUTH THIS AFTERNOON
DEVELOPS A NEW UPPER LEVEL LOW AT ITS BASE NEAR THE SEWARD
PENINSULA. ITS FRONT WILL PRODUCE A BAND OF PRECIPITATION, MOSTLY
LIGHT RAINFALL, ENTERING OVER THE INTERIOR KUSKOKWIM DELTA, AND
PUSHING WEST TO EAST, REACHING THE LOWER KUSKOKWIM VALLEY SATURDAY
MORNING. EXPECT A STEADY, BUT NOT STRONG NORTHWESTERLY FLOW OVER
MUCH OF SOUTHWEST ALASKA WITH FRONTAL PUSH. BRISTOL BAY TO REMAIN
RELATIVELY DRIER, GETTING A PERIOD OF RAIN FROM THIS FRONT BY
SATURDAY AFTERNOON. BY SUNDAY MORNING, THIS FRONT IS EXPECTED TO
WEAKEN AND SHIFT EAST OUT OF THE AREA, RETURNING SOUTHWEST ALASKA
TO A DRIER REGIME SUNDAY THROUGH MONDAY. COOLER AIR BEHIND THE
FRONT WILL KEEP THE TEMPERATURES IN THE MID TO UPPER 50'S THROUGH
THIS WEEKEND. TEMPERATURES WILL INCREASE INTO THE 60'S AGAIN EARLY
NEXT WEEK WITH AN INCOMING FRONT FROM THE BERING SEA.
HIGH PRESSURE RIDGING SCOOTS IN FROM THE CENTRAL ALEUTIANS,
KEEPING THE WEATHER IN THE REGION MOSTLY BENIGN, DOMINATED BY
WIDESPREAD LOW STRATUS AND AREAS OF FOG. BY EARLY SATURDAY
MORNING, A KAMCHATKA LOW PUSHES ITS FRONT INTO THE WESTERN BERING
SEA, BRINGING WITH IT A NEW SOURCE OF RAIN AND SMALL CRAFT WINDS.
A CORRIDOR OF GALE FORCE WINDS ARE LIKELY TO DEVELOP ALONG THE
WESTERN AND NORTHERN PORTIONS OF THE BERING BY SUNDAY MORNING,
MOVING EAST WITH THE FRONT. THE HIGH PRESSURE RIDGING WILL BE
FORCED EASTWARD TOWARDS SOUTHWEST ALASKA THROUGH THE WEEKEND AS
THE FRONT PROGRESSES ACROSS THE BERING TOWARDS THE SOUTHWEST
COAST. THE PACE OF THIS FRONT'S EASTWARD PROGRESSION WILL LARGELY
DEPEND ON THE MOVEMENT OF THE RIDGE, HOWEVER THE CURRENT EXPECTED
PACE WILL BRING THE AXIS OF THE FRONT OVER ADAK ISLAND BY SUNDAY
AFTERNOON.
LOOKING FORWARD TO THE START OF THE UPCOMING WORKWEEK, SOME MODEL
SOLUTIONS ARE ADVERTISING THE ARRIVAL OF A NORTH PACIFIC LOW
PHASING IN WITH THE FRONT. THIS AUGMENTATION WOULD AMPLIFY THE
WINDS AND PRECIPITATION POTENTIAL OF THE BOUNDARY, POTENTIALLY
BRINGING WINDS UP TO GALE FORCE FROM ATKA TO THE PRIBILOF ISLANDS
BY MONDAY AFTERNOON. HEAVY RAIN SHOWERS WOULD LIKELY ACCOMPANY
THIS REINVIGORATED FRONT, HOWEVER STAY TUNED AS WE CONTINUE TO
GATHER MORE INFORMATION ON THIS DEVELOPING SYSTEM.
-CL
.LONG TERM FORECAST (DAYS 4 THROUGH 7: TUESDAY THROUGH
FRIDAY)...
UPPER- LEVEL RIDGING AMPLIFIES ACROSS SOUTHCENTRAL ON TUESDAY
WHILE BROAD TROUGHING COVERS THE BERING SEA FROM THE ARCTIC TO THE
ALEUTIAN CHAIN. A SURFACE FEATURE MOVING ACROSS THE WESTERN AND
CENTRAL ALEUTIANS IS SET TO PULL IN AMPLE MOISTURE FROM THE
PACIFIC, DELIVERING THE PRIBILOF ISLANDS AND KUSKOKWIM DELTA COAST
WITH MODERATE RAIN TUESDAY. INCREASED SOUTHERLY GAP WINDS THROUGH
BAYS AND PASSES OF THE ALEUTIAN CHAIN WILL ALSO ENHANCE AS THIS
FEATURE PHASES WITH A STOUT CLOSED LOW NEAR THE BERING STRAIGHT.
THIS WAVE WILL QUICKLY MOVE ACROSS MAINLAND, BRINGING MOST OF
SOUTHERN ALASKA SOME RAIN ON WEDNESDAY. BEYOND THIS, MODEL
AGREEMENT DETERIORATES SIGNIFICANTLY. MOST OF THE STATE WILL BE
UNDER PRIMARILY ZONAL FLOW WITH SHORTWAVES MOVING THROUGH THE
PATTERN. EXPECT NEAR NORMAL TEMPERATURES WITH HIGHS FORECAST TO BE
GENERALLY IN THE 60'S.
AVIATION
PANC...ON-AND-OFF RAIN SHOWERS WILL PERSIST WITH CEILINGS AND
VISIBILITY GENERALLY REMAINING IN VFR. TURNAGAIN ARM WINDS WILL
BEND NORTH AND STRENGTHEN THROUGH THIS EVENING, PEAKING BETWEEN
06Z AND 09Z SATURDAY WITH GUSTS UP TO 20 TO 25 KTS, THEN WEAKENING
SATURDAY MORNING BEFORE RAMPING UP AGAIN IN THE AFTERNOON.
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