Area Forecast Discussion
Issued by NWS Anchorage, AK
Issued by NWS Anchorage, AK
804 FXAK68 PAFC 221344 AFDAFC Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 544 AM AKDT Wed May 22 2024 .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)... Cool and mostly cloudy weather is expected for much of southcentral Alaska over the next few days. Satellite imagery currently shows a large upper-level low currently positioned across western Alaska with one potent shortwave trough now ejecting east towards Yukon. Precipitation associated with this trough has brought fairly widespread rain (/high elevation snow) to the area over the past 24 hours, particularly along the coast where frontal precip + upsloping flow has resulted in approximately 0.25 to 1 inch of rain for much of the coastal communities along the Gulf of Alaska. While the primary band shifts east towards Yakutat, lingering precip along the Gulf Coast of the Kenai and Prince William Sound will pick back up later today, if it ever stops to begin with, as another shortwave trough begins to rotate across the area. Rain, lighter in intensity than along the coast, will also shift north up through the Kenai Peninsula later today and eventually towards Anchorage and the Mat-Su Valley. For much of the day, coastal ridging will continue to drive strong SE flow through the mountain gaps and Turnagain Arm. Downsloping, drying air may keep much, if not most, precip from falling to the surface on the west/north side of the mountains. The pressure gradient will relax tonight as a low develops across the north Gulf Coast in tandem with the primary upper-level trough axis shifting east. This will result in the strong Turnagain, Knik, and Copper River Basin winds gradually abating late today and tonight. Precipitation will pick up late tonight into tomorrow along the Richardson and Tok highways, north and east of Glennallen. Snowflakes may be seen down to approximately 2000` with some light snow accumulation towards Isabel and Mentasta passes. Outside of the Copper River Basin, much of Thursday will be dry or mostly dry for the area as ridging briefly moves overhead. This will be shortlived as the last weather-making upper-level low is quickly replaced with another. Precipitation will persist across the Gulf of Alaska coastal communities for much of Friday, with areas away from the Gulf also having a chance to receive at least some rain. One thing is for sure: it`ll remain cloudy for the days to come with temperatures remaining near or below climatological average. -Brown && .SHORT TERM FORECAST SOUTHWEST ALASKA, BERING SEA/ALEUTIANS (Days 1 through 3: Today through Friday)... Two storms move across the Bering Sea, Aleutian Islands, and Southwest Alaska through Friday, keeping unsettled weather in the forecast. Forecast confidence is relatively high; the biggest challenge will be forecasting minor snow accumulations for the Pribilof Islands and Kuskokwim Delta coast before precipitation changes over to rain late tonight into Thursday morning. No major hazards are being monitored at this time. The first storm is an occluded low currently moving onshore near Nunivak Island. Widespread showers across Southwest Alaska this morning will gradually taper off through the day. With cold air wrapping around the backside of the low and streaming in aloft, expect temperatures across Southern Alaska and the Pribilof Islands to dip near freezing tonight and early tomorrow morning. The second storm is a moderately strong low moving towards the Western Aleutians. Its front extends out ahead of it and is currently approaching the Central Aleutians. As the front treks eastward, lingering cold air will bring the potential for light snow accumulations along the Pribilof Islands late tonight, and for Nunivak Island and the Kuskokwim Delta coastline on Thursday morning. In addition to precipitation, this low will also bring a broad swath of gales and showers as cold air wraps back around the low. These stronger winds move across the Central Aleutians Thursday morning, then weaken as they move over the Eastern Aleutians Thursday evening. By Friday, widespread showers spread across Southwest Alaska as the occluding low center moves onshore. -KC && .LONG TERM FORECAST (Days 4 through 7) Saturday through Tuesday... The Eastern Bering upper level low continues to ooze its way Southeastward across the Alaska Peninsula, into and across the Gulf of Alaska through the beginning of the week. A rather energetic impulse over Northwestern Alaska helps flatten a Western Bering ridge, and draw a trough back into the Bering through the weekend, and helps establish a link-up with a second low out of the Russian Far East through Tuesday. With smaller troughs and weak surface low centers rotating through the pattern along the Aleutians, periods of rainfall are expected over the Aleutians, AKPEN, Kodiak Island and the Southern Kenai Peninsula through the forecast period. - Kutz && .AVIATION... PANC...VFR conditions will persist through at least this afternoon. Southeast winds will likely briefly reach back into the terminal ahead of a weakening front approaching form the southwest this afternoon, but should stay much weaker compared to yesterday evening. Winds will weaken and become southwesterly as the front moves past this evening. Rain showers will also move in as the winds shift around, potentially lowering ceilings into MVFR range this evening into tonight as a push of low level moisture moves up the Cook Inlet behind the front. && $$