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FXAK68 PAFC 071738 AAA
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
938 AM AKDT WED MAY 7 2025
UPDATED AVIATION DISCUSSION
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
THE LOW IN THE GULF CONTINUES TO SLOWLY MOVE SOUTHEAST. DUE TO
THE ORIENTATION OF THE LOW, PRESSURE GRADIENTS ARE STILL FAVORABLE
FOR GUSTY SOUTHEASTERLY WINDS OUT OF GAPS IN THE ANCHORAGE,
MATANUSKA VALLEY, AND THE COPPER RIVER BASIN AREAS. WINDS ARE
QUITE LIGHT EVERYWHERE ELSE, INCLUDING IN THE MARINE AREAS.
OUR FOCUS SHIFTS TO THE NORTH AS AN UPPER LEVEL LOW SWEEPS IN
FROM THE NORTHEAST ALONG THE ALASKA RANGE. THIS WILL DRIVE UP
PRECIPITATION CHANCES IN THE SUSITNA VALLEY AND THE COPPER RIVER
BASIN. THIS PRECIPITATION WILL BE STRATIFORM IN NATURE, SO EXPECT
WIDESPREAD LIGHT RAINFALL IN THESE REGIONS. SNOW AND RAIN HAS
ALREADY BEEN REPORTED IN GLENNALLEN THIS MORNING. SNOWFALL
ACCUMULATIONS IS POSSIBLE NORTH OF GLENNALLEN UP TO THE RICHARDSON
HIGHWAY THROUGH PAXSON AND THE TOK CUT OFF THIS MORNING.
ACCUMULATIONS OF ABOUT AN INCH OF SNOW IS POSSIBLE, MORE OR LESS
DEPENDING UPON HOW SOON TEMPERATURES WARM UP AND CHANGES TO
RAINFALL ALONG WITH INEVITABLE COMPACTION. THIS INTERIOR LOW WILL
ALSO ALLOW FOR MOSTLY CLOUDY SKIES DOWN TO ANCHORAGE AND PARTS OF
THE KENAI PENINSULA. THERE IS STILL SOME UNCERTAINTY WITH THIS
UPPER LEVEL LOW IN ITS TRACK AND ITS STRENGTH. ITS EXTENT
SOUTHWARD WILL AFFECT PRECIPITATION CHANCES AND LOWER CLOUD COVER
IN THE AFOREMENTIONED AREAS. WIND SPEEDS WILL NOT BE AFFECTED MUCH
BY THIS SYSTEM. DUE TO THE LOW PLACEMENT COINCIDING WITH THE GULF
LOW, SOUTHWESTERLY FLOW WILL BE FAVORABLE OVER THE NEXT COUPLE
DAYS. IN PARTICULAR, COOK INLET COMMUNITIES COULD EXPERIENCE
BREEZY SOUTH TO SOUTHWESTERLY WINDS ALL THE WAY INTO THE SUSITNA
VALLEY. SEA BREEZES ALONG THE KENAI-COOK INLET COAST AND ANCHORAGE
MAY BECOME ENHANCED DURING THE AFTERNOON, ESPECIALLY FOR
THURSDAY.
THE LOW ACROSS THE ALASKA RANGE WILL CONTINUE TO DRIFT WEST
THURSDAY AND PRECIPITATION CHANCES WILL GRADUALLY DIMINISH IN
RESPONSE. THE LOW IN THE GULF WILL STILL BE HANGING AROUND AND
WILL SWING A SHORTWAVE UP ALONG THE NORTHERN GULF FROM EAST TO
WEST, INCREASING WIND SPEEDS TO SMALL CRAFT ALONG THE COAST
FRIDAY. INLAND WINDS WILL REMAIN ON THE LIGHTER SIDE.
PRECIPITATION CHANCES ALONG THE COAST WILL INCREASE WITH THIS
WAVE. THE POTENTIAL FOR CONVECTIVE SHOWERS RETURNS THURSDAY AND
MORE SO FOR FRIDAY, BUT LIGHTNING CHANCES AT THIS TIME APPEAR TO
BE LOW.
-JAR/RUX
.SHORT TERM FORECAST SOUTHWEST ALASKA AND BERING SEA/ALEUTIANS
(DAYS 1 THROUGH 3: TODAY THROUGH SATURDAY MORNING)...
THE LOW PRESSURE THAT HAS BEEN STATIONARY SOUTH OF KODIAK ISLAND
THE LAST FEW DAYS CONTINUES TO SLOWLY WEAKEN AS IT MEANDERS
FARTHER SOUTHWARD INTO THE NORTH PACIFIC TODAY. A WEAK UPPER-LEVEL
LOW ACROSS INTERIOR ALASKA WILL HELP TO PRODUCE SOME SCATTERED
SHOWERS ACROSS THE SOUTHWESTERN INTERIOR THIS AFTERNOON. THERE IS
ALSO THE POSSIBILITY FOR A FEW ISOLATED THUNDERSTORMS AS WELL,
MAINLY ACROSS THE INTERIOR. THIS WILL BE THE CASE FOR THE NEXT FEW
AFTERNOONS AS WELL WITH LIGHTNING STRIKE POTENTIAL BEING
INCREASINGLY CONFINED TO THE INTERIOR AND WESTERN ALASKA RANGE.
MEANWHILE, A WEAK FRONT WILL DELIVER SOME LIGHT SNOW AND
RAIN/SNOW MIX TO THE PRIBILOF ISLANDS THIS MORNING BEFORE
PRECIPITATION TAPERS OFF IN THE AFTERNOON; LITTLE TO NO
ACCUMULATION IS EXPECTED. LIGHT RAIN SHOWERS ARE POSSIBLE ACROSS
THE EASTERN ALEUTIANS WITH THIS SYSTEM.
AN UPPER-LEVEL LOW SOUTH OF ST. LAWRENCE ISLAND HELP TO KEEP THE
WEATHER UNSETTLED ACROSS THE PRIBILOFS FOR THURSDAY WITH MORE
LIGHT SNOW AND RAIN/SNOW MIX AT TIMES. A WEAK AREA OF LOW PRESSURE
MAY CLIP THE KUSKOKWIM DELTA COAST AND NUNIVAK ISLAND THURSDAY
NIGHT INTO FRIDAY BRINGING SOME LIGHT SNOW TO THE AREA. THIS
ACTIVITY TAPERS OFF THROUGH FRIDAY MORNING.
A LARGER NORTH PACIFIC LOW WILL SEND ITS FRONT, ALONG WITH A PUSH
OF WARMER AIR, EASTWARD ACROSS THE ALEUTIANS THURSDAY THROUGH
SATURDAY. RAIN IS EXPECTED TO ACCOMPANY THIS FRONT, ALONG WITH
SMALL-CRAFT WINDS AND SOME GUSTS UP TO GALE-FORCE. GUSTY WINDS OUT
OF THE SOUTHEAST WILL PICK UP THROUGH THE GAPS AND PASSES OF THE
SOUTHERN ALASKA PENINSULA AND EASTERN ALEUTIANS STARTING THURSDAY
AS THE FRONT APPROACHES. COLD BAY LOOKS TO SEE THE GUSTIEST OF
WINDS WITH WINDS APPROACHING 40 MPH BY FRIDAY. THE LOW PRESSURE
ITSELF STRADDLES THE ALEUTIAN CHAIN AND MAKES IT THE CENTRAL
ALEUTIANS BY FRIDAY BEFORE LIFTING NORTHWARD TO THE CENTRAL BERING
SEA WEST OF THE PRIBILOFS FOR SATURDAY. WHILE THERE COULD BE SOME
RAIN/SNOW MIX AT THE ONSET OF PRECIPITATION ACROSS THE PRIBILOFS
SATURDAY MORNING, EXPECT MOSTLY RAIN DUE TO THE SOUTHEASTERLY
WINDS.
LONG TERM FORECAST (DAYS 4 THROUGH 7/SATURDAY THROUGH TUESDAY)
COMPARED TO YESTERDAY, MODEL GUIDANCE FOR THE DAY 4 THROUGH 7 TIME
PERIOD HAS TRENDED TOWARD A MORE AMPLIFIED UPPER LEVEL PATTERN.
MODEL SPREAD REMAINS QUITE LARGE WITH INDIVIDUAL STORMS AND
FEATURES, THOUGH THE LARGE SCALE EVOLUTION IS SIMILAR. STARTING
OUT ON SATURDAY, UPPER LEVEL RIDGING OVER SOUTHERN AK LOOKS
FAVORABLE TO PRODUCE A GOOD AMOUNT OF SUNSHINE, NORMAL TO ABOVE
NORMAL TEMPERATURES (IN THE 50S TO AROUND 60), AND MOSTLY DRY
CONDITIONS. MEANWHILE, A TROUGH WILL EXTEND FROM THE BERING SEA TO
THE GULF OF AK, WITH WEAK SURFACE LOWS LIKELY. MODEL SPREAD IS
PARTICULARLY LARGE WITH POSITION OF THE GULF LOW, WHICH CREATES
LOTS OF UNCERTAINTY IN THE WEATHER FOR KODIAK AND THE GULF COAST.
IN ANY CASE, ANY IMPACTS OF PRECIPITATION AND WIND WOULD BE SHORT-
LIVED. FOR NOW, THE FORECAST LEANS TOWARD THE ENSEMBLE MEAN WHICH
KEEPS THE BULK OF IMPACTS OFFSHORE.
AS WE CONTINUE THROUGH THE WEEKEND ATTENTION WILL SHIFT TO A
RAPIDLY DEEPENING LOW OVER THE NORTH-CENTRAL PACIFIC AND
ASSOCIATED AMPLIFICATION OF THE UPPER LEVEL FLOW. MODEL GUIDANCE
HAS TRENDED TOWARD A DEEPER LOW AND FURTHER WEST LOW TRACK, TAKING
THE LOW NORTHWARD INTO THE BERING SEA SOMETIME SUNDAY OR MONDAY.
EVEN WITH THE FASTEST OF SOLUTIONS, SOUTHERN ALASKA LOOKS MOSTLY
SUNNY AND DRY ON SUNDAY AS THE RIDGE BUILDING OUT AHEAD OF THE
PACIFIC LOW APPROACHES SOUTHERN AK. STRONG WINDS AND PRECIPITATION
WILL INITIALLY AFFECT THE BERING SEA AND ALEUTIANS. IN A CHANGE
FROM YESTERDAY, A FRONTAL SYSTEM WILL THEN DRIVE EASTWARD TOWARD
SOUTHERN AK, LIKELY BRINGING WINDS AND RAIN TO THE REGION MONDAY
THROUGH TUESDAY. WITH A LOW TRACK TO THE NORTHERN BERING SEA, WILL
NEED TO KEEP AN EYE ON POTENTIAL FOR STORM SURGE ALONG THE SW AK
COAST. UNSETTLED WEATHER WILL LIKELY CONTINUE BEHIND THE DEEP LOW,
WITH STRONG AND PROGRESSIVE UPPER LEVEL FLOW AND ADDITIONAL AREAS
OF CYCLOGENESIS (STORM DEVELOPMENT) OVER THE NORTH PACIFIC.
-SEB
AVIATION
PANC...VFR CONDITIONS WILL CONTINUE. LOTS OF UNCERTAINTY TODAY WITH
WINDS. THE TURNAGAIN ARM WIND CONTINUES THIS MORNING DESPITE SOME
MODEL GUIDANCE SHIFTING TO AND UP-INLET AND EVENTUALLY A SEA BREEZE
THIS AFTERNOON. HOWEVER, HIGHER RESOLUTION GUIDANCE KEEPS THE LIGHT
TURNAGAIN ARM WIND THROUGH THE EVENING. CURRENTLY THE TAF IS A MIX
OF THE UP-INLET FLOW AND WEAK TURNAGAIN WIND. THERE IS A STILL A
CHANCE THAT A SEA BREEZE DEVELOPS THIS AFTERNOON AND EVENING.
SHOWERS ARE LESS LIKELY TODAY, EVEN IF THEY DEVELOP, WILL REMAIN
ALONG THE MOUNTAINS.
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