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FXAK68 PAFC 061352
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
552 AM AKDT TUE MAY 6 2025
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
THE LOW OVER THE WESTERN GULF, SOUTH OF KODIAK ISLAND, IS SLOWLY
MOVING EASTWARD WITH RAIN ALONG THE NORTHERN GULF COAST AND
SHOWERS SPANNING ACROSS MOST OF THE GULF AND PRINCE WILLIAM SOUND.
SMALL CRAFT EAST TO NORTHEASTERLY WINDS AND SHOWERS WILL PERSIST
FOR THE GULF THROUGH TONIGHT. SOUTH TO SOUTHEAST TERRAIN GAPS AND
RIVER VALLEYS ACROSS SOUTHCENTRAL ALASKA WILL BECOME GUSTY AGAIN
THIS AFTERNOON. FARTHER INLAND, DAYTIME HEATING WILL ALLOW FOR
CONVECTION TO DEVELOP AGAIN FOR THIS AFTERNOON. THERE IS A SLIGHT
CHANCE FOR AN ISOLATED THUNDERSTORM TO DEVELOP ACROSS THE MAT-SU
VALLEY AND WESTERN KENAI PENINSULA WITH SLIGHTLY HIGHER CONFIDENCE
TOWARD THE SUSITNA VALLEY. SOME OF THE HIGH RESOLUTION MODELS
SUGGEST THAT THERE IS SOME POTENTIAL IN THE WESTERN COPPER RIVER
BASIN, BUT CONFIDENCE IS LOWEST THERE.
WEDNESDAY WILL BE SIMILAR TO TODAY AS THE MAIN LOW HARDLY TRACKS
VERY FAR INTO GULF. GUSTY WINDS RETURN WEDNESDAY AFTERNOON BUT
SPEEDS SHOULD BE WEAKER AS OVERALL SYNOPTIC FLOW ALSO BECOMES
SLIGHTLY WEAKER ACROSS SOUTHCENTRAL. SCATTERED SHOWERS WILL
CONTINUE ALONG THE NORTHERN GULF COAST AND FOR HIGHER ELEVATIONS.
CONVECTION HOWEVER, WILL NOT QUITE AS FAVORABLE. A WEAK LOW
NESTLED NEAR THE ALASKA RANGE COULD BRING UP INLET, SOUTHWESTERLY
FLOW, ADDITIONAL CLOUDS, AND PRECIPITATION TO THE INTERIOR
PORTIONS OF THE SUSITNA VALLEY AND COPPER RIVER BASIN. THERE IS
SOME UNCERTAINTY WITH HOW FAR SOUTH THE INTERIOR LOW WILL
INFLUENCE SOUTHCENTRAL. LOOKING INTO THURSDAY AFTERNOON, MODEL
AGREEMENT STARTS TO DIVERGE, BUT OVERALL SUGGESTS THE LOW NUDGES
SOUTH AND HIGHER PRESSURE BUILDS INTO SOUTHCENTRAL FROM THE ALASKA
INTERIOR, THUS DECREASING PRECIPITATION CHANCES. THE GULF LOW
BECOMES MORE DISORGANIZED AS IT WEAKENS, BUT EMBEDDED SHORTWAVES
COULD MAKE A REAPPEARANCE TO SOUTHCENTRAL FRIDAY AFTERNOON.
.SHORT TERM FORECAST SOUTHWEST ALASKA AND BERING SEA/ALEUTIANS
(DAYS 1 THROUGH 3: TODAY THROUGH FRIDAY MORNING)...
THE SYNOPTIC PATTERN CURRENTLY IS LITTLE CHANGED FROM THE LAST
FEW DAYS. A STUBBORN AREA OF LOW PRESSURE CONTINUES TO TAKE UP
REAL ESTATE SOUTH OF KODIAK ISLAND THIS MORNING AS IT CONTINUES TO
VERY SLOWLY DRIFT SOUTH WHILE WEAKENING. GUSTY NORTHERLY WINDS
ARE BEGINNING TO DIMINISH ACROSS THE EASTERN ALEUTIANS AND
SOUTHERN ALASKA PENINSULA (AKPEN) AS THE PRESSURE GRADIENT LOOSENS
BETWEEN THE LOW SOUTH OF KODIAK AND A RIDGE ACROSS THE CENTRAL
ALEUTIANS. RAIN AND SNOW SHOWERS ARE ALSO EXPECTED TO TAPER OFF
THROUGH TODAY ACROSS THE EASTERN ALEUTIANS AND SOUTHERN AKPEN.
SKIES ARE CLEARING THIS MORNING ACROSS PORTIONS OF THE
SOUTHWESTERN MAINLAND. THIS WILL ALLOW FOR DAYTIME HEATING AND
INSTABILITY TO BUILD FOR THIS AFTERNOON AND INTO THE EVENING. THE
BEST CHANCE OF ISOLATED THUNDERSTORMS WILL BE ACROSS THE
SOUTHWESTERN INTERIOR. HOWEVER, ENOUGH INSTABILITY COULD BE
PRESENT EVEN AROUND DILLINGHAM AND KING SALMON TO PRODUCE A COUPLE
LIGHTNING STRIKES WITH MORE VIGOROUS SHOWERS THAT DEVELOP.
ISOLATED THUNDERSTORM CHANCES CONTINUE FOR WEDNESDAY AND THURSDAY
AFTERNOONS WITH THE CHANCES BEING MORE CONFINED TO THE INTERIOR
LOCATIONS AS OPPOSED TO TODAY'S CHANCE.
FARTHER OUT WEST, A KAMCHATKA LOW SENDS ITS FRONT EASTWARD ACROSS
THE ALEUTIAN CHAIN TODAY THROUGH WEDNESDAY AS IT WEAKENS. THE
GUSTIEST OF THE WINDS, UP TO GALE-FORCE, ARE EXPECTED TO REMAIN
ACROSS THE WESTERN ALEUTIANS WITH SMALL-CRAFT GUSTS EXTENDING
ACROSS THE REST OF THE CHAIN BY WEDNESDAY. AN ADDITIONAL LOW MOVES
ACROSS THE NORTH PACIFIC AND EVENTUALLY TO THE WESTERN ALEUTIANS
AND WESTERN BERING SEA BY LATE THURSDAY NIGHT AS ITS FRONT
INITIALLY MOVES ACROSS THE ALEUTIAN CHAIN WEDNESDAY NIGHT THROUGH
FRIDAY MORNING SPREADING MAINLY RAIN ACROSS THE AREA. THE
STRONGEST WINDS ASSOCIATED WITH THIS STORM ARE EXPECTED TO BE
ALONG ITS SOUTHERN FLANK. THERE IS STILL SOME UNCERTAINTY WITH
REGARDS TO IF SUSTAINED GALE-FORCE WINDS MAKE IT INTO THE MARINE
ZONES ON THE NORTH PACIFIC SIDE OF THE WESTERN ALEUTIANS THURSDAY
NIGHT INTO FRIDAY.
LONG TERM FORECAST (DAYS 4 THROUGH 7/FRIDAY THROUGH MONDAY)
THE UPPER LEVEL FLOW WILL BE FAIRLY AMPLIFIED THROUGH THE EXTENDED
FORECAST PERIOD, BUT THE SUBTROPICAL JET STREAM WILL BE CENTERED
OVER THE NORTH PACIFIC. THIS WILL RESULT IN A FAIRLY COMMON
PATTERN FOR THIS TIME OF YEAR, WITH SOME LEVEL OF UPPER LEVEL
RIDGING PERSISTING OVER SOUTHERN AK. THIS WILL LEAD TO SOME
SUNSHINE MOST DAYS FOR SOUTHWEST AND SOUTHCENTRAL AK (ESPECIALLY
INLAND), WARMING TEMPERATURES, AND DIURNAL CONVECTION. MEANWHILE,
MORE ACTIVE WEATHER WILL PERSIST IN THE BERING SEA/ALEUTIANS AND
GULF OF ALASKA. A DEEP LOW IN THE BERING ON FRIDAY WILL GRADUALLY
WEAKEN OVER THE WEEKEND. A NEW LOW WILL MOVE OUT OF THE PACIFIC
AND TOWARD THE ALEUTIAN CHAIN ON SUNDAY, BUT MODEL SPREAD IN THE
TRACK IS LARGE. DEPENDING ON THE TRACK, THIS COULD AFFECT COASTAL
SW AK WITH RAIN AND WIND ON SUNDAY. YET ANOTHER DEEP LOW WILL MOVE
OUT OF THE NORTHWEST PACIFIC TO THE WESTERN ALEUTIANS ON MONDAY.
FOR THE GULF, A LOW WILL MOVE OUT OF THE NORTHEAST PACIFIC FRIDAY
NIGHT INTO SATURDAY, BUT WILL REMAIN OVER THE SOUTHERN GULF. AN
OCCLUDED FRONT WILL SPREAD OUT ALONG THE GULF COAST, BUT THE WORST
OF THE WEATHER WILL REMAIN OVER THE MARINE AREAS. THIS LOW WILL
THEN DISSIPATE ON SATURDAY. DEPENDING ON THE TRACK OF THE NORTH
PACIFIC LOW OUT WEST, A LOW OR FRONTAL SYSTEM COULD MOVE TO KODIAK
AND THE GULF ON MONDAY.
AVIATION
PANC...VFR CONDITIONS PREVAIL WITH CEILINGS 5000 FT OR GREATER
THROUGH THE TAF PERIOD. LIGHT AND VARIABLE WINDS CONTINUE THIS
MORNING BEFORE SOUTHEASTERLY TURNAGAIN ARM WINDS RETURN THIS
AFTERNOON, GUSTING AS HIGH AS 25 KNOTS THROUGH THE EVENING. WINDS
DIMINISH SOMEWHAT OVERNIGHT BUT GENERALLY REMAIN SOUTHEAST WITH
POTENTIAL TO GUST TO 20 KNOTS THROUGH WEDNESDAY.
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