Area Forecast Discussion
Issued by NWS Anchorage, AK
Issued by NWS Anchorage, AK
772 FXAK68 PAFC 260000 AFDAFC Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 400 PM AKDT Tue Jun 25 2024 .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)... In the upper levels, a ridge over mainland and a large low over the Bering Sea. The Bering low with its front will push eastward, reaching the western Gulf and Kodiak area on Wednesday and lingering through Thursday. The trough will phase with a Pacific low to keep southeasterly and onshore flow moving across the area. There is lower confidence with how far north and east into Southcentral this front will proceed as the low attempts to erode the mainland ridge. High pressure will weaken slightly with the additional embedded troughs pass moving through the ridge, but the overall pattern will likely remain blocked as the ridge holds stubbornly in place, preventing the low from progressing any farther east. Midlevel temperatures will remain quite warm over (10C to 14C), especially for the Copper River Basin and northerly Susitna Valley. Relatively cooler air (by just a few degrees) with along the front will help promote up Cook Inlet flow. Kodiak and portions of the southern Kenai Peninsula could be a little bit cooler and low stratus and fog will remain possible over the next few mornings. It is possible for cooler temperatures and low level moisture to reach into Anchorage and northern Cook Inlet, though confidence is much lower and primarily associated with the location the synoptic features. Isolated to scattered thunderstorms will remain possible for the Copper River Basin and Susitna Valley with easterly flow throughout the short term forecast. The midlevel temperatures will be warmest along the eastern slopes and foothills of the Talkeetnas and the Copper River Basin, helping to promote lift for thunderstorm development. Thunderstorms that develop will move in a northwesterly direction, spreading across the northern Copper River Basin and Susitna Valley. Due to the isolated and scattered nature of these storms, it is hard to pin point where QPF will be located exactly. However, recent thunderstorms have produced wetting rains and that will likely continue with any thunderstorm development. The highest convective potential will likely be Wednesday afternoon and evening, especially for more widespread scattered thunderstorms in the northern Susitna Valley, including the Alaska Range, and all the foothills surrounding the Copper River Basin. Potential decreases after midweek, becoming more isolated, though the eastern Alaska Range could hold onto some of that convective potential. rux && .SHORT TERM FORECAST SOUTHWEST ALASKA, THE BERING SEA/ALEUTIANS (Days 1 through 3: Tonight through Friday night)... Weak disturbances will continue tracking across interior Southwest Alaska this evening into Wednesday. As a result, scattered wet thunderstorms are possible this afternoon/evening and Wednesday afternoon/evening across eastern portions of the Middle Kuskokwim Valley and the Western Alaska Range. Cooler and more stable conditions arrive at the coast today and slowly work inland during the next couple of days as a result of a strong Bering Sea low. The surface low and its upper-level counterpart are currently centered over the southern Bering with its front extended across much of the Bering, the eastern Aleutians, and the AKPen. Steady rain and gale-force sustained winds accompany the front, with gusts up to storm force occurring through some bays and passes of the AKPen, particularly near Cold Bay. The front will continue lifting to Southwest Alaska and is expected the reach the coast Wednesday morning while the low itself still expands across most of the Bering. With the front, gale-force southeasterly winds and gusts up to 50 mph are expected to produce high surface along the northern Kuskokwim Bay coast (especially the communities of Kwigillingok and Kongiganak) from Wednesday morning through early Thursday morning. Thus, a High Surf Advisory is in effect for the northern Kuskokwim Bay coast. Waves and surf will peak Wednesday afternoon during high tide, with waves expected to rise 3 to 6 feet above the normal highest tide line. The front weakens on Thursday along the Southwest coast as the low itself slowly drifts to the northeast into the northern Bering. The bulk of the precipitation will be focused along the southern- facing side of the Kuskokwim Mountains (interior Bristol Bay) as a result of strong southeasterly cross-barrier flow, as well as the Kuskokwim Delta coast. On Friday, as this low continues weakening and tracking towards Russia, another system traverses the Aleutian Chain and heads towards the AKPen. Fenrich && .LONG TERM FORECAST (Days 4 through 7)... A ridge will remain over the area for the weekend for Southcentral and Copper River Basin. An isolated rain shower or thunderstorm is possible though into the beginning of next week. In the Southwest, a series of lows progress through the Bering Sea into the Interior Southwest bringing cooler temperatures, clouds and frequent rain showers to the area through the early next week. -DJ && .AVIATION... PANC... VFR conditions are forecast through the TAF period, with ceilings at or greater than 5000 ft. Winds will remain mostly southwesterly, with sporadic gusts as high as 20 kt in the afternoon and evening. Southwesterly up-inlet flow is expected to dominate southeasterly flow out of Turnagain Arm in the afternoons and evenings, but winds could shift more southerly if these opposing flows merge near the terminal. Otherwise, we are monitoring the potential for fog and low stratus to move up Cook Inlet again tomorrow, though confidence remains low. -KC && $$