199
FXAK68 PAFC 171205
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
405 AM AKDT FRI JUL 17 2026
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
AN UPPER LEVEL TROUGH CURRENTLY CENTERED NEAR MCGRATH WILL MOVE
SLOWLY NORTH INTO THE INTERIOR TODAY, CONTINUING THE ACTIVE AND
WET PATTERN THAT WE'VE SEEN THE MAJORITY OF THIS WEEK. SOME
INSTABILITY WILL BRING SHOWERS TO SOUTHCENTRAL TODAY AS IT LIFTS
NORTH, WITH STEADIER RAIN OUT EAST OVER FAR EASTERN THE COPPER
VALLEY. SOME CLEARING IS EXPECTED OVERNIGHT AND INTO SATURDAY
MORNING, PARTICULARLY OUT EAST, WITH SUBSIDENCE BEHIND THE TROUGH
LIFTING NORTH.
FOR THE WEEKEND, A DEEP UPPER LOW CURRENTLY NEAR THE PRIBILOF
ISLANDS WILL TRACK OVER THE ALASKA PENINSULA, BUT IN DOING SO WILL
GREATLY AMPLIFY THE PATTERN. GENERALLY SPEAKING THE UPPER LEVEL
TROUGH AND FOCUS OF MOST OF THE MOISTURE HAS SHIFTED SLIGHTLY TO
THE WEST FOR SATURDAY WITH MOST OF THE MOISTURE FOCUSED ON THE
SUSITNA VALLEY. ON SUNDAY THE TROUGH WILL MOVE SLIGHTLY EAST,
BRINGING AN ATMOSPHERIC RIVER INTO SOUTHCENTRAL. THE MOISTURE WILL
FOCUS PRIMARILY ON THE PRINCE WILLIAM SOUND AND SUSITNA VALLEY,
BUT SHORTWAVES MOVING THROUGH THE FLOW WILL BRING BOUTS OF RAIN TO
THE WESTERN KENAI, ANCHORAGE AND MAT VALLEY.
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(DAYS 1 THROUGH 3: TODAY THROUGH MONDAY MORNING)...
THE RELATIVELY ACTIVE PATTERN AS SEEN OVER THE PAST FEW DAYS
ACROSS THE SOUTHWESTERN MAINLAND, BERING, AND ALEUTIANS IS HERE TO
STAY; AT LEAST THROUGH THE SHORT-TERM PERIOD. CURRENTLY, A BROAD
TROUGH STRETCHES ACROSS MUCH OF THE BERING SEA AND THE ALASKAN
MAINLAND. AN UPPER-LEVEL LOW OVER SOUTHWEST ALASKA WILL MOVE NORTH
INTO INTERIOR AND WESTERN ALASKA THROUGH TODAY. HOWEVER, SHOWERS
WILL REMAIN IN THE FORECAST TODAY, ESPECIALLY ALONG THE COAST, AS
A STRONGER LOW PRESSURE CURRENTLY IN THE CENTRAL BERING AND WEST
OF THE PRIBILOF ISLANDS MOVES TOWARDS SOUTHWEST BY THIS EVENING.
THIS GALE-FORCE LOW MOVES TO THE PRIBILOF ISLANDS LATE THIS
MORNING AND TO ALONG THE SOUTHERN ALASKA PENINSULA (AKPEN) BY
SATURDAY MORNING. SUSTAINED GALE-FORCE SOUTHWESTERLY WINDS WILL
MOSTLY BE FELT ACROSS THE MARINE ZONES FROM ATKA TO UNALASKA,
UNIMAK PASS, AND TO SOUTH OF UNIMAK PASS FOR TODAY. AS COLD AIR
WORKS IN BEHIND THE SYSTEM, A CORRIDOR OF NORTHERLY TO
NORTHWESTERLY GALE-FORCE WINDS WILL DEVELOP WEST AND SOUTHWEST OF
THE PRIBILOF ISLANDS THIS AFTERNOON AND EVENING AND LASTS INTO
SATURDAY. LIGHT TO MODERATE RAIN WILL ACCOMPANY THIS DEEPENING
BERING LOW FROM THE PRIBILOFS AND ADAK/ATKA TO THE SOUTHERN AKPEN
TODAY. HEAVIER POCKETS OF RAIN REMAIN MORE CONFINED TO THE
SOUTHERN AKPEN BY TONIGHT WITH LIGHT RAIN ALONG THE SOUTHWEST
COAST.
THE BERING LOW, NOW IN THE SOUTHEAST BERING BY SATURDAY MORNING,
SLOWS ITS PROGRESSION AND REMAINS IN THE SOUTHEAST BERING THROUGH
EARLY SUNDAY MORNING BEFORE IT LIFTS TOWARDS KUSKOKWIM BAY LATE
SUNDAY MORNING. WITH LITTLE PROGRESSION AND NUMEROUS SHORTWAVES
ROTATING AROUND THE UPPER-LEVEL LOW PORTION OF THE SYSTEM, MOST OF
SOUTHWEST CONTINUES TO SEE RAIN THROUGH SATURDAY AND SUNDAY. IN
ADDITION TO THE RAIN ACROSS SOUTHWEST FOR SATURDAY, EXPECT GUSTY
EASTERLY TO SOUTHEASTERLY WINDS TO PICK UP THROUGH KAMISHAK GAP
AND INTO INTERIOR BRISTOL BAY AND ILIAMNA AS THE PRESSURE GRADIENT
TIGHTENS. THE GUSTIEST WINDS, AROUND 35 TO 40 MPH WILL BE FELT
ACROSS ILIAMNA SATURDAY EVENING WITH GUSTS UP TO 25 TO 30 MPH
ACROSS KOLIGANEK AND NEW STUYAHOK. THESE WINDS WILL SLOWLY
DIMINISH THROUGH SUNDAY AS THE PRESSURE GRADIENT WEAKENS. HOWEVER,
SOUTHEAST WINDS OUT OF KAMISHAK GAP WILL REMAIN THROUGH SUNDAY
WITH THE LOW IN KUSKOKWIM BAY. AS THE LOW MOVES TOWARDS KUSKOKWIM
BAY SUNDAY, IT WILL BE IN ITS WEAKENING PHASE WITH SMALL-CRAFT
SOUTHERLY TO SOUTHEASTERLIES LEFT OVER ACROSS BRISTOL BAY. RAIN
CONTINUES INTO MONDAY AS THE MAIN 500 MB TROUGH REMAINS DRAPED
ACROSS SOUTHWEST AND SHORTWAVES MOVE ACROSS THE AREA FROM THE
BERING AND NORTH PACIFIC.
ASIDE FROM THE RAIN THAT THE BERING LOW'S FRONT BRINGS THE
ALEUTIAN CHAIN TODAY, ADAK/ATKA DRY OUT FOR SATURDAY AS A
SHORTWAVE RIDGE BUILDS IN. NIKOLSKI/UNALASKA/AKUTAN STILL CONTEND
WITH SHOWERS AT TIMES SATURDAY WITH NORTHERLY FLOW OFF OF THE
BERING AND SHORTWAVES MOVING OVER THE AREA FROM THE NORTH ON THE
BACKSIDE OF THE LOW. MEANWHILE, SHOWERS ACROSS SHEMYA TAPER OFF
THIS AFTERNOON AS THE RIDGE BUILDS IN. ANY BREAK IN RAIN WILL BE
SHORT LIVED AS A SERIES OF SHORTWAVES MOVE OVER THE AREA FROM
KAMCHATKA STARTING TONIGHT THROUGH SUNDAY. ANOTHER SHORTWAVE RIDGE
DEVELOPS ACROSS THE WESTERN ALEUTIANS FOR MONDAY. STAY TUNED FOR
FORECAST UPDATES AS THE ACTIVE PATTERN ACROSS THE BERING,
ALEUTIANS, AND SOUTHWESTERN MAINLAND CONTINUES TO UNFOLD.
.LONG TERM FORECAST (DAYS 4 THROUGH 7: MONDAY THROUGH
THURSDAY)...
PERSISTENCE REMAINS THE KEYWORD FOR THE LONG-TERM PERIOD. THERE
REMAINS THE STRONG SIGNAL IN THE GLOBAL MODELS OF A SLOW MOVING,
HIGHLY AMPLIFIED, UPPER LEVEL TROUGH CONSOLIDATING ALONG 165TH
WEST MERIDIAN AND LINGERING ACROSS MUCH OF ALASKA WELL INTO THE
MIDDLE OF THE UPCOMING WORKWEEK. SMALLER SCALE DETAILS ARE LESS
CERTAIN, ESPECIALLY WITH EMBEDDED SHORTWAVES ROUNDING THE BASE OF
THE TROUGH AND MOVING INTO THE GULF OF ALASKA, WHERE MODERATE
STORM DEVELOPMENT IS POSSIBLE OVER THE SOUTHERN BERING SEA AND
NORTHERN GULF. THIS PATTERN SUPPORTS AN EXTENDED UNSETTLED STRETCH
OF DAILY RAIN CHANCES REGION WIDE THOUGH PRECIPITATION WILL TURN
MORE WIDESPREAD, ORGANIZED AND WINDIER FROM THE SOUTHWEST THROUGH
PRINCE WILLIAM SOUND AND SOUTHCENTRAL ALASKA AS MOISTURE DEEPENS
AND SHIFTS NORTHWARD. A MULTI-DAY HEAVY RAINFALL THREAT HAS BEEN
HIGHLIGHTED FOR THOSE AREAS NEXT WEEK. THE MAIN FORECAST CHALLENGE
THROUGH THE LONG TERM REMAINS THE TIMING OF THE SHORTWAVES (WHICH
WILL DRIVE PERIODS OF MODERATE RAINFALL) ROTATING AROUND THE
LARGE UPPER LEVEL TROUGH COMPLEX THAT WILL ANCHOR OVER THE EASTERN
BERING SEA.
ALONG THE COASTAL WATERS, PARTICULARLY THE GULF OF ALASKA AND
SOUTHERN BERING SEA, STRENGTHENING SYSTEMS CARRY THE POTENTIAL FOR
INCREASING WINDS AND ROUGHER SEAS. THESE CONDITIONS ARE LIKELY TO
CREATE HAZARDOUS MARINE ENVIRONMENT FOR BOATING, COMMERCIAL
FISHING AND VESSEL OPERATIONS, WITH HEAVIER SEAS AND GUSTY WINDS
POSSIBLE. OVERALL, THE WETTER AND WINDIER PATTERN ACROSS SOUTHERN
AND COASTAL ALASKA WILL REQUIRE ATTENTION TO ACCUMULATING RAINFALL
IMPACTS AND MARINE HAZARDS INTO THE MIDDLE OF NEXT WEEK.
-DD
AVIATION
PANC...AN UPPER LEVEL WAVE WILL CONTINUE TO PROGRESS NORTH TODAY,
BRINGING SHOWERS THROUGH MOST OF THE DAYTIME PERIOD. CIGS AND VIS
SHOULD STAY VFR BUT MVFR IS POSSIBLE DURING PERIODS OF RAIN THIS
AFTERNOON. LIGHT NORTHERLIES WILL TRANSITION TO SOUTHERLY AROUND
MIDDAY.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page