![National Oceanic and Atmospheric Administration](/build/images/header/noaa.d87e0251.png)
![National Weather Service](/build/images/header/nws.4e6585d8.png)
![United States Department of Commerce](/build/images/header/doc.b38ba91a.png)
Area Forecast Discussion
Issued by NWS Anchorage, AK
Issued by NWS Anchorage, AK
453 FXAK68 PAFC 190057 AFDAFC Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 457 PM AKDT Tue Jun 18 2024 .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Today through Thursday night)... The upper level ridge that has been promoting the clear and convective pattern over interior Southcentral is starting to edge eastward as a front is pushing northward toward the southwest Gulf. This pattern shift toward a more unstable airmass approaching coastal Southcentral will push any remaining convective potential northward in the Copper River Basin this afternoon and evening. Areas of marine stratus that pushed up Cook Inlet the last few mornings has dissipated, and is expected to continue diminishing in presence the next few mornings as the ridge moves eastward. Some patchy fog may form over the marine zones, but this should dissipate rapidly as the day warms. Where the stratus has not dissipated is over the Gulf and Prince William Sound. The subsidence from the ridge and persistent southwest flow onto the coast will make it difficult for this stratus to clear out until Wednesday of even Thursday. Therefore expecting from Seward to Valdez to Cordova to remain under this marine stratus through tonight. By Thursday, the pattern will have shifted enough to have cleared out the low clouds, but with southeast flow aloft, more general cloudiness is expected over Southcentral for the end of the week. The stable stratus marine layer clouds over the northern Gulf of Alaska to be replaced by stratiform clouds from the incoming trough, all-in-all little change in sky coverage expected for places like Kodiak. With the change in stability for Kodiak however, light rain has begun, and is expected to continue for Kodiak the next few days. && .SHORT TERM FORECAST SOUTHWEST ALASKA, THE BERING SEA/ALEUTIANS (Days 1 through 3: This afternoon through Friday afternoon)... Fairly benign weather persists through Friday afternoon as the storm track remains south of Alaska. Several lows moving along the periphery of the forecast area will keep periods of breezier and wetter weather in the forecast, but no particularly hazardous weather is expected at this time. Instead, the primary weather to watch for Southwest Alaska will be the potential for thunderstorms this afternoon, and on Thursday and Friday afternoons. For the Bering Sea and Aleutian Islands, a ridge will bring the potential for widespread low stratus and fog. Forecast confidence is fairly good at the large scale, but there are a few forecast details where uncertainty is greater. One such detail will be the areal coverage and severity of fog across the Bering Sea and Aleutian Islands. For now, have introduced a large area of fog to the Western and Central Bering/Aleutians. Fog is inherently difficult to forecast because it relies on small-scale interactions that weather models have difficulty representing. Further complicating this is the scarcity of weather observations in the Bering Sea and along the Aleutian Chain, making it difficult for us to monitor patches of fog moving through the area. Subsidence under the ridge and plentiful moisture from the Bering Sea will likely lead to areas of fog, but the difficulty will be determining exactly where and exactly how thick the fog may be. The other forecast element with lower confidence is thunderstorm potential. Currently, weather models are showing instability across parts of Southwest Alaska for Thursday afternoon and Friday afternoon. Thursday afternoon`s convection forecast will be complicated by the potential for lingering cloud cover as a North Pacific low will be located just south of the Alaska Peninsula. Friday afternoon looks a bit better, but there are differences in where the best thermal instability (and therefore, convective initiation) will occur. Current thinking is that the Middle Kuskokwim Delta and Western Alaska Range have the best chances of seeing thunderstorms on both afternoons, with the potential for Kuskokwim Delta to see thunderstorms Thursday afternoon if cloud cover clears enough. -KC && .LONG TERM FORECAST (Days 4 through 7: Saturday through Tuesday)... Mainland Alaska remains under the influence of an upper level ridge extending from Northwestern Canada through the forecast period. Warmer than normal temperatures are expected over the Southern half of the Mainland. On the surface, thermal troughs support widespread convection. Arctic areas continue under a broad low, with the Northwestern Bering low looping back into Siberia for Tuesday. A very broad low stretches from Kamchatka across the Aleutians and Bering into the Gulf of Alaska and Eastern North Pacific. Model guidance continues in good confidence through most of the period, but outliers develop into the new week. A series of troughs slip along the Aleutians, spreading showers over the Alaska Peninsula Southwest Alaska and Kodiak Island through Tuesday. In the far West, a better organized front moves into the Central Aleutians and Bering through Tuesday. A trough from the Eastern North Pacific low brings showers to coastal locations from the Canadian Border to Prince William Sound for the weekend. -Kutz && .AVIATION... PANC...Areas of stratus continue to linger around portions of the Cook Inlet this afternoon with any MVFR ceilings in the northern reaches of the inlet expected to become VFR by late afternoon. VFR conditions are expected to continue from late this afternoon through tomorrow. -CC && $$