711
FXAK68 PAFC 220008
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
408 PM AKDT SUN JUN 21 2026
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
CURRENTLY, A NORTH PACIFIC LOW IS MOVING INTO THE GULF OF ALASKA.
THIS LOW IS PUSHING MOISTURE UP INTO SOUTHCENTRAL, LEADING TO
SCATTERED SHOWERS ALONG THE COAST AND INTO THE KENAI PENINSULA.
MEANWHILE, ISOLATED SHOWERS AND THUNDERSTORMS ARE FORMING IN THE
TALKEETNA MOUNTAINS AND THE COPPER RIVER BASIN AS INSTABILITY
REMAINS ELEVATED. SHORTWAVES FROM THE LOW ARE CREATING A COASTAL
RIDGE OVER THE CHUGACH RANGE. THIS WILL ALLOW FOR ELEVATED
SOUTHEASTERLY WINDS (10 TO 15 MPH) IN PALMER, SOUTH ANCHORAGE,
AND THE COPPER RIVER BASIN TODAY THROUGH MONDAY. MONDAY WILL BE
SIMILAR TO TODAY EXCEPT WITH INCREASED SHOWER ACTIVITY AS THE LOW
MOVES FURTHER INTO THE GULF AND ADDITIONAL SHORTWAVES PUSH INTO
SOUTHCENTRAL. THE ANCHORAGE AREA WILL BE DOWNSLOPED DUE TO
EASTERLY FLOW, BUT LIGHT RAIN SHOWERS WILL STILL HAVE A 20 TO 30%
CHANCE OF OCCURRING.
BY TUESDAY, A STRONG SHORTWAVE FROM THE LOW WILL MOVE ACROSS
SOUTHCENTRAL FROM THE EAST. THIS WAVE WILL PRODUCE A DEFORMATION
BAND, WHICH WILL CAUSE MODERATE TO HEAVY RAIN FIRST IN HIGHER
ELEVATIONS OF THE ALASKA RANGE AND THE TALKEETNA MOUNTAINS. LOWER
ELEVATION AREAS INCLUDING ANCHORAGE WILL SEE LESS RAINFALL DUE TO
DOWNSLOPING, BUT THE SHEER AMOUNT OF MOISTURE MAKING IT IN WILL
ALLOW AT LEAST 0.05 TO 0.10 INCHES OF RAIN TO FALL. BY TUESDAY
AFTERNOON, THE BAND OF MODERATE TO HEAVY RAINFALL WILL MOVE OVER
THE NORTHERN AND WESTERN SUSITNA VALLEY INCLUDING TALKEETNA AND
SKWENTNA, WHERE IT WILL LINGER THROUGH WEDNESDAY. BETWEEN TUESDAY
AND WEDNESDAY, BETWEEN 1 AND 3 INCHES OF RAINFALL WILL FALL
DEPENDING ON WHERE THE BAND OF RAIN SETS UP. THERE IS UNCERTAINTY
WITH THIS EVENT AND IF THE RAIN BAND SETS UP FURTHER WEST, THE
LOWER AMOUNTS OF RAINFALL WILL BE SEEN. CONVERSELY, IF THE RAIN
BAND SETS UP FURTHER EAST, THE HIGHER END OF THE RANGE WILL BE
MORE LIKELY. BY WEDNESDAY EVENING, RAINFALL WILL DECREASE IN
INTENSITY AS THE LOW MOVES MORE TO THE EAST AND THE STRONG
SHORTWAVE INLAND DISSIPATES. ADDITIONAL SHORTWAVES WILL MOVE
THROUGH, BUT THESE WILL NOT BE NEARLY AS STRONG AND RAINFALL
ASSOCIATED WITH THEM WILL BE LIGHTER.
-JAR
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3: TODAY THROUGH TUESDAY)...
GENERALLY UNSETTLED WEATHER CONTINUES AS A COMPLEX UPPER LEVEL
LOW SPANNING FROM THE SOUTHERN BERING INTO THE NORTH PACIFIC
CONTINUES TO CONSOLIDATE IN THE SOUTHWESTERN GULF THROUGH SUNDAY.
WIDESPREAD SHOWERS CONTINUE ACROSS SOUTHWEST ALASKA AND THE ALASKA
PENINSULA THIS MORNING AS A SURFACE LOW SLOWLY DRIFTS NORTH
TOWARDS KODIAK ISLAND. FOR BRISTOL BAY, ALASKA PENINSULA, AND
ACROSS MUCH OF THE BERING SEA, EXPECT AREAS OF FOG AND LOW CLOUDS
TO ALSO LINGER. FOR ADAK/ATKA AND WEST, A FRONT WILL BRING
SUSTAINED WINDS 25 TO 35 KT THROUGH MONDAY AFTERNOON BEFORE IT
STALLS AND DISSIPATES BY MONDAY NIGHT. NO MAJOR HAZARDS ARE
ANTICIPATED AT THIS TIME.
THUNDERSTORM POTENTIAL CONTINUES TO REMAIN THE BIGGEST CHALLENGE
AS SHORTWAVES ALONG THE NORTHERN PERIPHERY OF THE UPPER LOW
CONTINUE TO TRACK WEST ACROSS INTERIOR SOUTHWEST. DESPITE THE
INCREASING CLOUD COVER AND LACK OF ROBUST SURFACE HEATING,
OCCASIONAL BREAKS IN THE CLOUDS ACROSS THE KUSKOKWIM VALLEY AND
KUSKOKWIM DELTA THIS AFTERNOON SHOULD ONCE AGAIN PROVIDE ENOUGH
INSTABILITY TO TAKE ADVANTAGE OF THE ENHANCED LIFT PROVIDED BY
SHORTWAVES MOVING THROUGH THE REGION. ISOLATED THUNDERSTORM
DEVELOPMENT (20% TO 30% CHANCE) THIS AFTERNOON IS MOST LIKELY
ACROSS THE KUSKOKWIM VALLEY FROM SLEETMUTE WESTWARD AND ACROSS THE
KUSKOKWIM DELTA. AND AS WE'RE RIGHT ON THE CUSP OF THE SUMMER
SOLSTICE, LONG DAYS COULD LEAD TO THUNDERSTORM ACTIVITY CONTINUING
WELL INTO THE EVENING AND OVERNIGHT HOURS. GENERALLY EXPECT THE
FOOTPRINT OF THUNDERSTORMS TO DECREASE THROUGH THE FIRST HALF OF
THIS WEEK AS THE LOW LINGERING NEAR KODIAK ISLAND WILL LIKELY
BRING INCREASED CLOUDS AND REDUCED SURFACE HEATING.
-JH/KC
.LONG TERM FORECAST (DAYS 4 THROUGH 7: THURSDAY THROUGH
SUNDAY)...
AN UNSETTLED PATTER IS EXPECTED TO PERSIST ACROSS SOUTHCENTRAL
ALASKA AND THE ALEUTIANS THROUGH THE END OF THE WEEK INTO THE
WEEKEND. A BROAD UPPER TROUGH AND SURFACE LOW PRESSURE OVER THE
GULF OF ALASKA WILL MAINTAIN EXTENSIVE CLOUD COVER AND PERIODIC
SHOWERS ACROSS SOUTHCENTRAL. THE GREATEST PRECIPITATION CHANCES
WILL REMAIN ALONG THE COASTAL MOUNTAINS AND WINDWARD TERRAIN,
THOUGH SCATTERED INLAND SHOWERS ARE ALSO EXPECTED DURING THE
AFTERNOON AND EVENING HOURS. TEMPERATURES SHOULD REMAIN NEAR TO
SLIGHTLY BELOW SEASONAL NORMALS UNDER THE PERSISTENT CLOUD COVER.
FARTHER WEST, A BERING SEA LOW WILL GRADUALLY TRACK EASTWARD
TOWARD THE ALEUTIANS, BRINGING PERIODS OF RAIN AND LOCALLY GUSTY
WINDS TO THE ISLAND CHAIN THROUGH LATE WEEK. AS THE SYSTEM MOVES
INTO THE WESTERN MAINLAND, IT WILL BECOME ABSORBED INTO A MORE
ZONAL WESTERLY FLOW ALOFT, ALLOWING PRECIPITATION CHANCES TO
SPREAD EASTWARD WHILE KEEPING GENERALLY UNSETTLED CONDITIONS IN
PLACE THROUGH SUNDAY.
MEANWHILE, A RIDGE CENTERED OVER THE CENTRAL BERING WILL PROMOTE
COMPARATIVELY QUIETER WEATHER ACROSS THE ALASKA PENINSULA AND
PORTIONS OF SOUTHWEST ALASKA. HOWEVER, DAYTIME HEATING AND WEAK
INSTABILITY MAY STILL SUPPORT ISOLATED AFTERNOON SHOWERS,
PARTICULARLY ALONG THE WESTERN SLOPE OF HIGHER TERRAIN.
FORECAST CONFIDENCE DECREASES TOWARD THE LATTER HALF OF THE PERIOD
AS MODEL SOLUTIONS DIVERGE ON THE EVOLUTION AND PLACEMENT OF THE
BERING LOW AND ASSOCIATED UPPER-LEVEL FEATURES. DESPITE THESE
DIFFERENCES, CONFIDENCE REMAINS MODERATE THAT MUCH OF SOUTHERN
ALASKA WILL STAY COOLER, SHOWERY, AND GENERALLY UNSETTLED PATTERN
THROUGH SUNDAY.
LM
AVIATION
PANC...VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE PERIOD.
A TURNAGAIN ARM WIND WILL DEVELOP THIS AFTERNOON/EVENING AND HAS
A CHANCE OF PRODUCING GUSTS UP TO 20 KTS BEFORE DIMINISHING BY
AROUND 14Z MONDAY MORNING.
FIRE WEATHER
FOR SOUTHCENTRAL ALASKA:
A RED FLAG WARNING REMAINS IN EFFECT FOR SOUTHERN, CENTRAL,
WESTERN AND NORTHERN SUSITNA VALLEY AND THE LOWER MATANUSKA VALLEY
DUE TO LIGHTNING UNTIL 1 AM AKDT SATURDAY.
DISCUSSION: SCATTERED SHOWERS AND WET THUNDERSTORMS HAVE
DEVELOPED THIS AFTERNOON ACROSS THE SUSITNA VALLEY, MAINLY ALONG
THE EASTERN SLOPES OF THE TALKEETNAS AND WEST OF THE TALKEETNAS
WHERE TEMPERATURES HAVE WARMED WELL INTO THE 70S TODAY. STORM
MOTION IS SLOW TODAY AND TO THE NORTHWEST WITH TIME. ALTHOUGH
THESE STORMS ARE PRODUCING LOCALLY HEAVY DOWNPOURS AND COULD DROP
SOME SMALL HAIL, THE PRIMARY CONCERN IS FREQUENT LIGHTNING STRIKES
OUTSIDE OF AREAS THAT SEE RAINFALL FOR POTENTIAL FIRE STARTS.
STORM COVERAGE WILL LIKELY INCREASE AS THE AFTERNOON WEARS ON AND
BEGIN TO DECREASE LATE THIS EVENING AS WE LOSE DAYTIME HEATING AND
ASSOCIATED UPPER LEVEL ENERGY EXITS THE REGION. A FEW REMNANT
SHOWERS COULD LINGER EARLY SATURDAY MORNING. THERE IS MEDIUM TO
HIGH (70-80%) CONFIDENCE THAT THE FOCUS FOR THUNDERSTORM ACTIVITY
SATURDAY AFTERNOON WILL LIKELY SHIFT EASTWARD TO THE COPPER RIVER
BASIN, MEANING LESS STORM COVERAGE ACROSS THE SUSITNA VALLEY AND
LOWER MATANUSKA VALLEY.
FOR SOUTHWEST ALASKA:
A RED FLAG WARNING REMAINS IN EFFECT FOR LIME VILLAGE DUE TO
LIGHTNING UNTIL 1 AM AKDT SATURDAY.
DISCUSSION: THE FORECAST LOOKS ON TRACK REGARDING THE RED FLAG
WARNING IN EFFECT THROUGH TONIGHT. SCATTERED WET THUNDERSTORMS
ARE CURRENTLY DEVELOPING OFF THE FOOTHILLS OF THE WESTERN ALASKA
RANGE IN LIME VILLAGE, WITH THE EXPECTATION THAT 10 TO 15 KT OF
STEERING FLOW WILL LEAD TO NORTHWEST PROPAGATION OF THUNDERSTORMS
THROUGH THE EVENING. GIVEN MODELED CAPE RANGING FROM 300-700 J/KG,
THESE THUNDERSTORMS MAY PRODUCE HAIL AND GUSTY WINDS IN ADDITION
TO FREQUENT LIGHTNING. FOR TOMORROW, HAVE INCREASED THE FOOTPRINT
OF THUNDERSTORMS ACROSS THE KUSKOKWIM RIVER CORRIDOR FROM THE
COAST TO LIME VILLAGE, BUT CONFIDENCE IS LOWER REGARDING WHERE
THERE MAY BE WIDELY SCATTERED OR PERHAPS EVEN SCATTERED
THUNDERSTORMS. WHILE MAX SURFACE-BASED CAPE LOOKS LOWER FOR
TOMORROW, THERE LOOKS TO BE A LARGER FOOTPRINT OF 200-400 J/KG,
WHICH WOULD LIKELY BE SUFFICIENT TO PRODUCE WIDELY SCATTERED
THUNDERSTORMS. HOWEVER, THERE IS POOR MODEL AGREEMENT REGARDING
WHERE THE HIGHEST CAPE WILL BE; AS SUCH, HAVE PUT IN A PRELIMINARY
AREA OF WIDELY-SCATTERED THUNDERSTORMS IN KUSKOKWIM VALLEY EAST
AND LIME VILLAGE WHERE TEMPERATURES WILL LIKELY BE WARMEST AND
SKIES CLEAREST.
-AM/KC
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