Area Forecast Discussion
Issued by NWS Anchorage, AK
Issued by NWS Anchorage, AK
166 FXAK68 PAFC 250058 AFDAFC Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 458 PM AKDT Mon Jun 24 2024 .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Monday afternoon through Thursday afternoon)... Thunderstorms and warm temperatures will continue to dominate Southcentral weather through mid-week, though there will be a gradual pattern change as a Bering Sea low pushes its front towards Kodiak Island on Wednesday. Forecast confidence is about typical, though the thunderstorm forecast (especially for Wednesday and Thursday) will likely be updated as high-resolution model data becomes available to use for the forecast. Diving into the details... an upper level ridge continues to dominate weather across the state. Weak upper level shortwaves moving around the ridge are helping to spur areas of showers and thunderstorms, with the most prominent convection occurring in the Copper River Basin and along the Talkeetna Mountains today. Further south, an upper low exiting Bristol Bay is also bringing thunderstorms to Kodiak Island as it transits overhead. Between Kodiak Island and the Mat-Su Valleys, an influx of clouds and moister air is helping to keep things more stable. While a thunderstorm or two aren`t out of the question for Western Kenai Peninsula and the Anchorage area, convection is expected to be less robust than yesterday. From Tuesday through Thursday, thunderstorm potential will remain mostly limited to the Copper River Basin and Talkeetna Mountains as surface high pressure and moist, southerly flow help to inhibit convective activity. For Anchorage and the north Gulf coast, the main story will be the return of breezy onshore winds, mostly in the afternoon, as a pressure gradient sets up between the ridge in the Gulf and the thermal trough inland. For Kodiak Island and parts of Eastern Kenai Peninsula, the main story will be the approaching front on Wednesday. The front will be quite weak when it reaches Kodiak Island, with winds expected to remain below 25 kt in coastal waters and rain remaining fairly light. Though precipitation will be limited mostly to the Western Gulf, increasing cloud cover will overspread much of Southern Alaska, bringing an end to our recent spell of sunny days. -KC && .SHORT TERM FORECAST SOUTHWEST ALASKA, THE BERING SEA/ALEUTIANS (Days 1 through 3: Tonight through Thursday)... The remnants of a Bristol Bay low continue to track south while a ridge over the Bering Sea begins to breakdown in response to a shortwave upper-level trough lifting up across the western Aleutians into the southern Bering. Weak disturbances will continue tracking across interior Southwest this evening and tonight. As a result, scattered wet thunderstorms will persist from the Western Alaska Range across the Kuskokwim Valley to inland areas of the Kuskokwim Delta. By Tuesday, a cooler more stable pattern begins to spread inland across Southwest. However, some scattered thunderstorms are still possible along the Western Alaska Range later Tuesday afternoon and evening. Farther out west, a compact surface low, associated with the aforementioned trough, approaches the Aleutian Chain and southern Bering. The low and its front will gradually track to the northeast and encompass much of the Bering and Aleutians through Thursday. Steady rain and sustained winds up to gale force are anticipated. Gusts up to storm force are likely for bays and passes along the AKPen, particularly near Cold Bay. The front begins to weaken as it reaches the Southwest coast on Wednesday morning, but gusts upwards of 50 mph are still possible for locations along the immediate coastline as the front arrives. 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. On Thursday, the low itself continues to drift northeast to the northern Bering and spreads rain to the Kuskokwim Delta. Winds gradually diminish through Thursday. Fenrich && .LONG TERM FORECAST (Days 4 through 7)... A ridge of high pressure in the Interior will continue to dominate through weekend resulting in an isolated rain shower or thunderstorm. High pressure in the Gulf of Alaska will keep the Southcentral dry into the beginning of next week. 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 weekend. -DJ && .AVIATION... PANC...Flow up Inlet and through Turnagain Arm has produced more stable low levels compared with Sunday. In addition, storm motion has shifted and any showers and thunderstorms which form on/along the mountains this afternoon and evening will track from SSE to NNW. Thus, expect the vast majority of convection to remain near the mountains and be more isolated in nature across the northwest Kenai Peninsula and Front Range Chugach than on Sunday. While there could be some debris clouds and a mid level ceiling tonight, conditions will remain VFR. Gusty southerly winds are favored this afternoon into the overnight hours with a combination of the up-Inlet SW winds and the SE Turnagain winds. For Tuesday, winds up Cook Inlet will be weaker while the Turnagain Arm jet looks a bit stronger, so expect a more typical slightly stronger Se winds coming in mid afternoon. && $$