871
FXAK68 PAFC 191230
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
430 AM AKDT SUN JUL 19 2026
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
THE ATMOSPHERIC RIVER IS NOW IN PLACE STREAMING MOISTURE FROM AS
FAR SOUTH AS 40N INTO THE KENAI PENINSULA, COOK INLET, PWS AND THE
SUSITNA VALLEY. THE FLOOD WATCH REMAINS IN EFFECT FOR SEWARD
THROUGH TUESDAY MORNING. RIVERS THROUGHOUT THE REGION WILL RISE
SIGNIFICANTLY TODAY, SO FISHERMAN AND RECREATORS SHOULD EXERCISE
CAUTION. THROUGH THE DAY TODAY THERE WILL BE A SLIGHT SHIFT IN
THE WINDS ALOFT TO BE MORE SOUTH- SOUTHEAST, WHICH MAY HELP TO DRY
OUT THE ANCHORAGE AREA AND MAT VALLEY SLIGHTLY THIS AFTERNOON AS
GAP WINDS MOVE BACK INTO THE AREA. THE COPPER VALLEY AND TO SOME
EXTENT KODIAK ISLAND WILL AVOID MOST OF THE RAIN FROM THE AR
TODAY.
FOR MONDAY, THE UPPER TROUGH WILL TAKE ON A NEGATIVE TILT AND
BEGIN TO MOVE EAST. THIS WILL PROVIDE THE BEST LIFT FOR THE
ANCHORAGE AREA AND MAT VALLEY, WHICH WILL RECEIVE SOME MODERATE
RAIN THROUGHOUT THE DAY. SOME UNCERTAINTY REMAINS WITH HOW FAST
THE SYSTEM WILL PUSH EAST, WITH THE NAM REALLY CLEARING THINGS OUT
QUICKLY MONDAY EVENING. THIS FORECAST PACKAGE LINGERS THE RAIN A
LITTLE LONGER AND MORE IN LINE WITH THE GLOBAL MODELS DUE TO THE
STRENGTH OF THE HIGH TO THE EAST. FOR TUESDAY THERE WILL BE A
BRIEF BREAK IN THE MORNING AS ANOTHER SYSTEM MOVES IN FROM THE
WEST, BRINGING SOUTHWEST FLOW ALOFT, MORE GAP WINDS AND MORE RAIN
STARTING IN THE AFTERNOON TO EVENING. THIS SYSTEM WILL PUSH
THROUGH OVERNIGHT AND DROP INTO THE GULF. THE MOVEMENT OF THE
SYSTEM SOUTH INTO THE GULF WILL START THE PATTERN CHANGE BACK TO
DRIER WEATHER LATER IN THE WEEK AS RIDGING TRIES TO BUILD IN FROM
THE WEST.
.SHORT TERM FORECAST SOUTHWEST ALASKA
(DAYS 1 THROUGH 3: TODAY THROUGH WEDNESDAY MORNING)...
THE LOW IN BRISTOL BAY WILL CONTINUE TO BRING ONSHORE FLOW AND
RAIN SHOWERS TO THE MAINLAND AND AK PEN INTO SUNDAY EVENING AS IT
SLOWLY MOVES ONSHORE THIS WEEKEND. AS THIS LOW FINALLY DEVOLVES
INTO AN OPEN TROUGH MONDAY MORNING, SHOWERS ALONG THE COAST
FINALLY MOVE MORE INLAND THROUGH THE DAY MONDAY. ALSO, PERSISTENT
NORTHERLY FLOW IN THE CENTRAL ALEUTIANS AND NORTHWEST FLOW IN THE
WESTERN ALEUTIANS RESULTS IN CONTINUED WIND GUSTS RANGING FROM 35
TO 45 MPH THROUGH THE WEEKEND.
THE NEXT WEATHER-MAKER BEGINS TO TAKE SHAPE THIS AFTERNOON AS A
ROBUST UPPER-LEVEL SHORTWAVE MOVES OFF OF THE COAST OF EASTERN
RUSSIA TODAY. A SURFACE LOW PRESSURE WILL FORM OFF OF THE EASTERN
RUSSIA COAST ALONG A BAROCLINIC ZONE THIS AFTERNOON AND EVENING.
THIS LOW WILL THEN TRACK TO THE SOUTHEAST BETWEEN THE PRIBILOF
ISLANDS AND SAINT MATTHEW ISLAND BY MONDAY NIGHT AS ITS FRONT
BRINGS STEADY RAIN TO THE PRIBILOF ISLANDS,
NIKOLSKI/UNALASKA/AKUTAN, AND THE SOUTHERN ALASKA PENINSULA
(AKPEN) THROUGH MONDAY.
THE TRACK CURRENTLY DEPICTED BY GUIDANCE HAS TRENDED A LITTLE
BACK TO THE SOUTH SINCE YESTERDAY'S FORECAST PACKAGE AND A LITTLE
WEAKER AS WELL. GUIDANCE IS STILL TRYING TO HASH OUT THE ULTIMATE
TRACK OF THIS LOW THROUGH TUESDAY. 00Z AND 06Z GUIDANCE HAS THE
SYSTEM TRACKING NORTH OF THE PRIBILOF ISLANDS, BUT SOUTH OF OR
RIGHT NEAR NUNIVAK ISLAND BY TUESDAY AFTERNOON. THIS MORE SOUTHERN
SOLUTION AS WOULD HAVE LESS OF A SOUTHWESTERLY PUSH UP KUSKOKWIM
BAY FOR TUESDAY. THE WIND PUSH WOULD MOSTLY BE SOUTHEASTERLIES
INTO THE NORTHERN KUSKOKWIM BAY COAST. WITH THAT SAID, THE TIDAL
INFLUENCE LOOKS MINIMAL FOR TUESDAY FOR LOCATIONS SUCH AS
KWIGILLINGOK AND KIPNUK. REGARDLESS OF A LITTLE SOUTH SHIFT IN
TRACK, EXPECT WIDESPREAD RAIN TO MOVE UP THE AKPEN AND FROM THE
COAST TO THE INTERIOR OF SOUTHWEST ALASKA THROUGH TUESDAY.
THE ACTIVE PATTERN CONTINUES FOR WEDNESDAY AS A MORE ZONAL WEST-
TO-EAST FLOW TAKES OVER THE BERING. ANOTHER PUSH OF WARM TROPICAL
AIR ALSO ACCOMPANIES THIS ZONAL FLOW. EMBEDDED UPPER-LEVEL
SHORTWAVE ENERGY WILL CAUSE A RESURGENCE OF RAIN ACROSS THE ENTIRE
ALEUTIAN CHAIN, PRIBILOF ISLANDS, AKPEN, AND INTO SOUTHWEST
ALASKA. THE POSITION OF THE RIDGE SOUTH OF THE ALEUTIAN CHAIN AND
AND DIGGING TROUGH ACROSS EASTERN RUSSIA WILL DICTATE WHERE THE
CORRIDOR OF HEAVIEST RAIN SETS UP. CONFIDENCE IS RELATIVELY HIGH
THAT HEAVY RAIN WILL BE OBSERVED WEDNESDAY BUT LOW ON EXACTLY
WHERE THAT HEAVY RAIN CORRIDOR WILL SET UP. STAY TUNED FOR
FORECAST UPDATES AS THIS WET, WINDY, AND ACTIVE PERIOD CONTINUES
TO UNFOLD.
.LONG TERM FORECAST (DAYS 4 THROUGH 7: WEDNESDAY THROUGH
SATURDAY)...
FORECAST MODELS ARE SHOWING SIGNS THAT PERSISTENT TROUGHING OVER
THE BERING MAY FINALLY BREAK DOWN OVER THE LATTER HALF OF NEXT
WEEK. SOUTHWESTERLY FLOW, STILL IN PLACE ON WEDNESDAY, BEGINS TO
WEAKEN AND SHIFT EASTWARD AS A RIDGE OF HIGH PRESSURE NUDGES INTO
THE BERING FROM THE WEST. THIS COULD SPELL A TEMPORARY REPRIEVE
FROM OUR WET PATTERN ACROSS MUCH OF ALASKA BY THE END OF THE LONG
TERM FORECAST ON SATURDAY. BEFORE THE WEEKEND ARRIVES, HOWEVER,
EXPECT ABOVE NORMAL PRECIPITATION CHANCES TO CONTINUE AS MULTIPLE
WAVES OF LOW PRESSURE TRACK THROUGH SOUTHERN ALASKA FROM THE
BERING.
-BL
AVIATION
PANC...RAIN WILL CONTINUE THIS MORNING BUT STRONGER WINDS OVER THE
MOUNTAINS SHOULD KEEP CONDITIONS VFR. FOR NOW, A DOWN-INLET
GRADIENT IS KEEPING SURFACE WINDS LIGHT AND VARIABLE, WHILE WINDS
AROUND 2KFT ARE STRONG OUT OF THE EAST SOUTHEAST, THUS GENERATING
SOME LLWS. THE TURNAGAIN WIND THIS AFTERNOON IS EXPECTED TO BE
ERRATIC, LIKELY COMING IN AND OUT OF THE TERMINAL, LEADING TO
PERIODS OF LLWS.
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