650
FXAK68 PAFC 011303
AFDAFC
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
503 AM AKDT TUE APR 1 2025
SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 3)
THERE IS VERY LITTLE CHANGE IN THE OVERALL PATTERN FOR MUCH OF
SOUTHCENTRAL THROUGH AT LEAST THURSDAY MORNING. WITH UPPER LEVEL
RIDGING ENCOMPASSING A LARGE CHUNK OF SOUTHCENTRAL AND THE GULF OF
ALASKA, MOSTLY DRY CONDITIONS ARE EXPECTED TO CONTINUE ACROSS THE
REGION, WITH SOME HIGHER ELEVATION UPSLOPE PRECIPITATION POSSIBLE
ALONG THE ALASKA RANGE AND TALKEETNA MOUNTAINS. MOSTLY SUNNY TO
PARTLY CLOUDY SKIES TODAY AND TOMORROW FOR AREAS ALONG THE COAST,
AS WELL AS ANCHORAGE, WESTERN KENAI AND THE MAT VALLEY. HIGH CLOUD
COVER SPILLS OVER INTO PORTIONS OF THE COPPER RIVER BASIN AND
SUSITNA VALLEY AS WEAK SHORTWAVES MOVE OVER TOP THE RIDGE.
INCREASED CLOUD COVER RETURNS THE MOST AREAS BY THURSDAY AS A
NORTH PACIFIC FRONT EDGES INTO THE REGION. ADDITIONALLY, THERE IS
AN INCREASED CHANCE FOR LIGHT PRECIPITATION AND HIGHER ELEVATION
SNOW (MAINLY ALONG THE COAST) AS THE FRONT APPROACHES.
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (DAYS
1 THROUGH 3: TODAY THROUGH WEDNESDAY)...
ACTIVE WEATHER IS ONGOING ACROSS BOTH SOUTHWEST ALASKA AND THE
BERING THIS MORNING. WATER VAPOR IMAGERY SHOWS MULTIPLE WEAK
DISTURBANCES OVER THE BERING ARE HELPING TO FLATTEN A RIDGE OF
HIGH PRESSURE LOCATED OVER THE ALEUTIAN CHAIN. UPSTREAM OF THE
RIDGE, A BROADER TROUGH IS BEGINNING TO TAKE SHAPE OVER THE
WESTERN BERING AND WESTERN ALEUTIANS. A DISSIPATING FRONT HAS
SAGGED SOUTHWARD INTO THE KUSKOKWIM DELTA AND WESTERN PORTIONS OF
THE LOWER KUSKOKWIM VALLEY, AND MAINTAINED A BARRAGE OF LOW
STRATUS, PERIODS OF FOG, AND LIGHT SNOW. BETHEL AND ANIAK, IN
PARTICULAR, HAVE BOUNCED BETWEEN ONE AND FOUR MILES OF VISIBILITY
THROUGH MUCH OF THE OVERNIGHT HOURS. A TROUGH OVER THE BERING WILL
PUSH INTO THE KUSKOKWIM COAST LATER THIS EVENING AND WILL LIKELY
CONTRIBUTE TO ADDITIONAL PERIODS OF REDUCED VISIBILITY FROM LIGHT
PRECIPITATION. AREAS FURTHER SOUTH ACROSS THE GREATER BRISTOL BAY
REGION HAVE REMAINED LARGELY DRY AND ARE FORECAST TO STAY DRY
INTO WEDNESDAY.
OUT OVER THE WESTERN ALEUTIANS, A TROUGH AND FRONT ARE QUICKLY
APPROACHING THE CENTRAL ALEUTIANS. WARMER TEMPERATURES IN THE
UPPER 30S ARE FORECAST TO GRADUALLY COOL THROUGH THE AFTERNOON.
ANY DEVELOPMENT OF LIGHT RAIN WILL TRANSITION TO SNOW THROUGH
TONIGHT WITH PERHAPS A COUPLE OF INCHES IN THE WAY OF ACCUMULATION
POSSIBLE. WHAT REMAINS OF THE FRONT WILL CLIP THE PRIBILOF
ISLANDS LATER THIS AFTERNOON AND EVENING WITH A SHORT ROUND OF
LIGHT RAIN.
BEHIND THE WESTERN BERING TROUGH AND FRONT, A MUCH COOLER AIRMASS
IS FORECAST TO SPREAD ACROSS THE BERING THIS AFTERNOON AND INTO
WEDNESDAY WHILE HIGH PRESSURE, PREVIOUSLY OVER THE ALEUTIANS,
SHIFTS EASTWARD INTO THE GULF OF ALASKA. WHILE DETAILS ARE STILL
BEING RESOLVED, IT IS BECOMING INCREASINGLY LIKELY THAT THE
PHASING OF A DEEPENING TROUGH WITH A DEEP NORTH PACIFIC LOW WELL
SOUTH OF THE EASTERN ALEUTIANS WILL COMMENCE. A SUBSTANTIAL
DEFORMATION BAND THEN FORMS OVER THE EASTERN ALEUTIANS WITH
PRECIPITATION EXPANDING IN COVERAGE AS THE NORTH PACIFIC LOW WRAPS
NORTHWARD INTO THE ALASKA PENINSULA THROUGH THURSDAY. THIS WILL
PRESENT SOME CHALLENGES WITH DETERMINING WHERE A NORTH-TO-SOUTH
FREEZING LINE STALLS SOMEWHERE BETWEEN UNALASKA AND COLD BAY.
CONFIDENCE IS RELATIVELY HIGH THAT UNALASKA IS IN STORE FOR AN
EXTENDED PERIOD OF MODERATE TO HEAVY SNOW, BEGINNING SOME TIME ON
THURSDAY, WHILE AREAS TO THE EAST MAY MIX WITH RAIN AT TIMES,
DECREASING POTENTIAL SNOW ACCUMULATIONS. THE CONTINUED SOUTH
ADVECTION OF COLD AIR WILL ALSO SIGNAL STRONG NORTHERLY WINDS
THROUGH THE SOUTHERN BERING AND INTO THE EASTERN ALEUTIANS, WHICH
COULD HAVE BLIZZARD IMPLICATIONS IF THE RIGHT INGREDIENTS ALIGN.
STAY TUNED FOR MORE.
-BL/AM
LONG TERM FORECAST (DAYS 4 THROUGH 7: FRIDAY TO MONDAY)
AN UPPER LEVEL TROUGH OVER CENTRAL BERING ELONGATES SOUTHWARD ACROSS
THE ALEUTIANS THURSDAY INTO FRIDAY. THIS IS FOLLOWED BY A STRONG
LOW PRESSURE SYSTEM THAT LIFTS FROM THE NORTH PACIFIC TOWARD THE
ALASKA PENINSULA FRIDAY AFTERNOON. WIDESPREAD GALES ARE EXPECTED
ACROSS THE ALEUTIAN CHAIN AND NORTHERN GULF COAST. THE MOST
INTENSE WINDS ARE EXPECTED TO ARRIVE FRIDAY AFTERNOON ACROSS THE
ALASKA PENINSULA. SOUTHERLY FLOW WILL BRING ABOVE AVERAGE
TEMPERATURES AND MOSTLY RAIN FOR AREAS EAST OF THE ALASKA
PENINSULA. NORTHERLY FLOW TO THE WEST WILL BRING SNOW TO UNALASKA,
WITH RECORD APRIL SNOWFALL AMOUNTS POSSIBLE (8 INCHES OR GREATER)
THROUGH SATURDAY MORNING, AND LIGHTER RATES CONTINUING THROUGH
SUNDAY AFTERNOON. SEVERAL INCHES OF RAIN ARE EXPECTED FOR KODIAK,
THE EASTERN KENAI PENINSULA, AND NORTHERN GULF COAST WHILE THE LOW
TRACKS SLOWLY EASTWARD, SOUTH OF KODIAK ISLAND AND THE WESTERN
GULF THROUGH MONDAY.
.AVIATION...
PANC...VFR CONDITIONS AND LIGHT WINDS WILL PERSIST.
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