962
FXAK68 PAFC 141253
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
453 AM AKDT MON JUL 14 2025
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH
3/TODAY THROUGH WEDNESDAY EVENING)...
THE UPPER-LEVEL RIDGE THAT WAS IN PLACE OVER THE SOUTHERN HALF OF
THE STATE HAS NOW SHIFTED SOUTHEAST WITH ITS AXIS OVER THE ALASKA
PANHANDLE THIS MORNING. A DEVELOPING SOUTHWESTERLY FLOW UPSTREAM
OF THE RIDGE AND AHEAD OF AN UPPER-LEVEL TROUGH OVER THE EASTERN
BERING IS ADVECTING CLOUDS AND MOISTURE FROM KODIAK NORTH TO THE
KENAI PENINSULA. THE RESULT IS A FEW SCATTERED SHOWERS FROM AROUND
KACHEMAK BAY INTO THE SUSITNA VALLEY AND WESTERN COPPER RIVER
BASIN THIS MORNING.
THE SHOWER ACTIVITY IS EXPECTED TO BECOME MORE WIDESPREAD THROUGH
THE DAY AS A WEAK SURFACE LOW OVER BRISTOL BAY THIS MORNING OPENS
INTO A TROUGH AND SLIDES EAST ALONG WITH AN UPPER-LEVEL SHORTWAVE
LIFTING TO THE KENAI PENINSULA. THERE IS NOT MUCH MOISTURE FOR
EITHER SYSTEM TO WORK WITH, SO THE SHOWER ACTIVITY IS LIKELY TO
BE ENHANCED BY THE SOUTHWESTERLY UPSLOPE FLOW, WRINGING OUT OVER
THE HIGHER TERRAIN. THAT SAID, SHOWERS MAY EXTEND ACROSS VALLEY
LOCATIONS AND OVER THE ANCHORAGE BOWL LATER TODAY AS THE TROUGH
AXIS MOVES OVER COOK INLET AND THE FLOW ALOFT SHIFTS SLIGHTLY
MORE SOUTHERLY. MODELS THEN DIVERGE A BIT WITH REGARD TO HOW
QUICKLY THE TROUGH KICKS EAST, WITH SOME GUIDANCE INDICATING A
WEAKER TRAILING WAVE SLIDING EAST IN THE WAKE OF THE FIRST. IF
THIS SOLUTION PANS OUT, THERE MAY BE LINGERING SHOWERS ACROSS THE
ANCHORAGE BOWL AND MAT-SU VALLEYS THROUGH TUESDAY MORNING.
BY TUESDAY AFTERNOON, A RIDGE BUILDS INTO THE GULF OF ALASKA.
THIS RIDGE WILL ALLOW MUCH OF SOUTHCENTRAL TO DRY OUT AND ANY
LINGERING ISOLATED SHOWERS TO PUSH NORTH ALONG THE ALASKA RANGE
AS THE FLOW ALOFT SHIFTS FROM THE SOUTHWEST TO THE SOUTHEAST.
ON WEDNESDAY, A NORTH PACIFIC LOW WILL APPROACH FROM THE WEST.
THIS IS WHERE THINGS GET COMPLICATED AS MODEL AGREEMENT DECREASES.
GUIDANCE IS NOW CLUSTERING THE LOW SOMEWHERE NEAR KODIAK ISLAND
BY WEDNESDAY MORNING AS ITS SURFACE FRONT ADVANCES ACROSS THE
WESTERN GULF AND TOWARD THE KENAI PENINSULA. UNCERTAINTY GROWS
WITH HOW QUICKLY THE FRONT PROGRESSES NORTHEASTWARD THROUGH
WEDNESDAY AS IT RUNS INTO THE RIDGE. THE NAM CONTINUES TO BE THE
FASTEST SOLUTION AND THE OUTLIER COMPARED TO OTHER MODELS, WITH
THE GEM STILL AN OUTLIER WITH A MORE EASTERLY TRACK. GIVEN THE
STRENGTH OF THE RIDGE AND AMPLIFICATION OF THE LONGWAVE PATTERN,
FORECAST UPDATES THIS MORNING FAVOR THE SLIGHTLY STRONGER YET
SLOWER AND SLIGHTLY FARTHER WEST TRACK OF THE GFS AND EC.
REGARDLESS OF THE TRACK, THIS SYSTEM DOES LOOK TO BRING RAIN TO
KODIAK ISLAND, THE KENAI PENINSULA, AND PRINCE WILLIAM SOUND BY
WEDNESDAY MORNING AND EVENING, RESPECTIVELY, AS THE FRONT
EVENTUALLY ENTERS THE NORTHERN GULF.
-JAR/TM
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(DAYS 1 THROUGH 3: TODAY THROUGH WEDNESDAY)...
NIGHTTIME MICROPHYSICS SATELLITE IMAGERY SHOWS A KALEIDOSCOPE OF
HIGH AND LOW CLOUDS ACROSS THE BERING AND SOUTHWEST ALASKA THIS
MORNING, WITH AREAS OF FOG IN AND AROUND DUTCH HARBOR AND
PORTIONS OF THE SOUTHERN BERING. THE WEATHER PATTERN REMAINS
ACTIVE WITH A TROUGH QUICKLY APPROACHING NUNIVAK ISLAND AND THE
KUSKOKWIM DELTA COAST, AN UPPER LOW SOUTH OF THE ALASKA PENINSULA,
AND A SECOND TROUGH MOVING THROUGH THE WESTERN ALEUTIANS.
A CHANCE FOR SCATTERED SHOWERS WILL PERSIST ACROSS SOUTHWEST
ALASKA THIS AFTERNOON AND EVENING AS A RESULT OF THE FIRST TROUGH.
THE LOW SOUTH OF THE ALASKA PENINSULA IS FORECAST TO LIFT
NORTHWARD THROUGH TOMORROW, EVENTUALLY REACHING BRISTOL BAY BY
WEDNESDAY MORNING. EXPECT INCREASING SHOWER CHANCES TO EXPAND
NORTHWARD OVER THE ALASKA PENINSULA TUESDAY NIGHT, WITH WIDESPREAD
SHOWER CHANCES TO UNFOLD ACROSS SOUTHWEST ALASKA THROUGH
WEDNESDAY EVENING. THIS WILL SEE A COOLING TREND FOR SOUTHWEST
THROUGH THE MIDDLE OF THE OF THE WEEK.
WHILE A SECOND TROUGH IS MOVING INTO THE WESTERN ALEUTIANS THIS
MORNING, MORE NOTABLE IS A DEVELOPING LOW CURRENTLY OVER
KAMCHATKA. THIS LOW DEEPENS THROUGH TOMORROW, WITH A STRONG FRONT
TO BRING RAIN AND GUSTY CONDITIONS, INCLUDING GALES, INTO THE
CENTRAL ALEUTIANS BY TUESDAY MORNING. WEAK RIDGING OVER THE
EASTERN BERING SHOULD WEAKEN THE FRONT JUST AS IT BRINGS RAIN TO
THE PRIBILOF ISLANDS LATE TUESDAY AFTERNOON, WITH SHOWER ACTIVITY
FURTHER ALONG THE FRONT ALSO STALLING NEAR UNALASKA AS THE FRONT
DISSIPATES.
THERE ARE NO CHANGES TO THE ACTIVE PATTERN LATER IN THE WEEK WITH
THE DEVELOPING KAMCHATKA LOW TO AMPLIFY OVER THE SOUTHERN BERING
ON THURSDAY. THIS SHOULD SEE A RATHER LARGE FRONT PUSH INTO THE
EASTERN ALEUTIANS AND SOUTHWEST ALASKA THURSDAY INTO FRIDAY WITH
RENEWED RAIN CHANCES.
-BL
.LONG TERM FORECAST (DAYS 4 THROUGH 7: THURSDAY THROUGH
SUNDAY)...
THE LONG RANGE FORECAST FOR THE REGION STARTS WITH A LOW IN THE
NORTHWESTERN GULF OF ALASKA AND ANOTHER LOW IN THE WESTERN BERING
SEA. MODELS ARE CONTINUING TO STRUGGLE WITH THE PLACEMENT AND
EVOLUTION OF THE LOW IN THE GULF OF ALASKA. THE GFS MOVES THE LOW
TO THE NORTHEAST INTO CANADA BY FRIDAY AFTERNOON, THE CANADIAN
SHOWS THE LOW TRACKING TO THE NORTH AND BEING ABSORBED INTO THE
AFOREMENTIONED BERING LOW, AND THE ECMWF HAS THE GULF LOW MOVING
DUE EAST THEN DISSIPATING BEFORE REACHING THE ALASKA PANHANDLE BY
FRIDAY EVENING. THEREFORE, CONFIDENCE ON PRECIPITATION AND SKY
CONDITIONS IS STILL LOW. TOWARDS THE END OF THE LONGTERM, A
BLOCKING HIGH PRESSURE PATTERN BUILDS ACROSS THE COPPER RIVER
BASIN AND SHOULD PROMOTE A BETTER CHANCE FOR LESS CLOUDS AND DRIER
CONDITIONS. WITH LITTLE MIXING, AIR QUALITY COULD BECOME AN ISSUE
IN THE REGION.
IN THE BERING SEA, THE LOW PRESSURE SYSTEM GENERALLY REMAINS OVER
THE BERING DURING MOST OF THE LONGTERM WHILE HIGH PRESSURE
STRENGTHENS OVER THE AK MAINLAND. THE MAIN UNCERTAINTY WITH THE
BERING LOW IS IN REGARDS TO HOW IT INTERACTS WITH SURROUNDING
SHORTWAVES/LOWS AND THE SPEED OF ITS SURFACE FRONT. THE GFS
SOLUTION WOULD PUSH THE FRONT QUICKLY ACROSS SW AK AND PORTIONS OF
SOUTHCENTRAL (WITH THE BULK OF PRECIPITATION ACROSS SW ON
SATURDAY MORNING), WHEREAS THE CANADIAN FRONT IS SLOWER (WITH THE
BULK OF PRECIPITATION ACROSS SW ON SUNDAY MORNING). NONETHELESS,
EXPECT AN ACTIVE PATTERN OUT WEST DURING THE LONG TERM PERIOD.
-DD
AVIATION
PANC...VFR CONDITIONS WILL GENERALLY PERSIST FOR THE TAF PERIOD,
THOUGH CEILINGS WILL LIKELY BE BELOW 5,000 FT. A SHORTWAVE TROUGH
LIFTING INTO SOUTHCENTRAL WILL BRING MORE CLOUDS AND OCCASIONAL
RAIN SHOWERS THROUGHOUT THE DAY MONDAY, WHICH COULD BRIEFLY DROP
CEILINGS TO MVFR. THE TURNAGAIN ARM ALSO PICKS UP MONDAY AFTERNOON
WITH UP-INLET FLOW, WHICH COULD BRING SOUTHERLY TO SOUTHWESTERLY
WIND GUSTS UP TO 20 KTS. WINDS SHOULD BEGIN TO RELAX HEADING INTO
MONDAY NIGHT.
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