Area Forecast Discussion
Issued by NWS Anchorage, AK
Issued by NWS Anchorage, AK
436 FXAK68 PAFC 021245 AFDAFC Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 445 AM AKDT Tue Jul 2 2024 .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)... Not much change to the overall pattern is expected for the next couple days as a low meandering close to Kodiak pulls south into the North Pacific and a weak ridge of high pressure spanning along a west-east axis slowly builds over Southcentral through Wednesday. A couple very weak waves rotating around this ridge from the Yukon this morning will help set off areas of rain showers across the northeastern half of the Copper Basin today. None of this activity is looking too impressive, and little more than a tenth of an inch of rainfall is expected for any part of the Copper Basin before showers mostly dissipate by this evening. Away from the briefly cooler and showery pattern setting up to the northeast, it looks like a better afternoon at least is in store across western parts of the outlook area. Scattered to broken cloud cover in place this morning across the Mat-Su and Kenai Peninsula is expected to erode somewhat with subsidence drying around the developing upper level ridge drifting in from the north. Despite the strengthening high pressure, low level flow will remain south to southwesterly (especially near the Cook Inlet), and this will tamp down highs in the low to mid 60s for much of the region even with partial sun returning. Much of the same is expected for Wednesday as the narrow ridge remains mostly intact and the Gulf low moves even farther out into the Pacific. By Thursday (July 4th), hints of a bigger pattern change will begin to be felt by some. A series of shortwaves interacting with a band of moisture streaming around the ridge from the Bering Sea into the Interior will begin to encroach from the north, with a stronger trough expected to approach the Alaska Range by the afternoon. Increasing cloud cover will spread in from north to south through the evening, with steady light rain also spreading in ahead of the wave first into the Susitna Valley, then expanding south towards the Matanuska Valley late in the evening. Fortunately, it doesn`t look like a washout holiday for most, with the best potential for rainfall holding off until very late in the day for all but portions of the Susitna Valley. -AS && .SHORT TERM FORECAST SOUTHWEST ALASKA, BERING SEA/ALEUTIANS (Days 1 through 3)... High pressure ridging builds over Southwest Alaska today, cutting off precipitation for most areas but bringing in some patchy fog and/or low ceilings along the coast today. Shortwaves riding overtop the ridge will drop south into Southwest Alaska late Wednesday night/early Thursday morning. This will allow for a shift to a more rainy pattern beginning in the Kuskokwim Delta before tracking eastward. Further west, a front extending off a Kamchatka low moves into the western Bering Sea this morning, bringing widespread rain showers to the Western and Central Aleutians. && .LONG TERM FORECAST (Days 4 through 7: Friday through Monday)... The ridge of high pressure over Southcentral Alaska will start to gradually weaken through early next week. This, coupled with an approaching frontal system from the west, will produce a southeasterly wind flow across the area. Cooler temperatures and sporadic widespread precipitation over the region is possible over the long 4th of July weekend. Precipitation should remain in the mid to upper elevations but we cannot rule out intermittent rain over much of Southcentral Alaska and the Copper River Basin through Monday. Several troughs of low pressure extending from a cutoff low in the North Pacific will bring some heavier periods of precipitation across Kenai Peninsula, Kodiak Island and the Northern Alaskan Peninsula through Monday afternoon. Out west, the Bering/Aleutians and Southwest Alaska can also expect showery conditions through the weekend as an upper-level trough and multiple shortwaves rotate across the regions. -DD && .AVIATION... PANC...VFR conditions expected to persist Tuesday into Wednesday while weakening ridge of high pressure over interior Alaska sags southward into the region. Light southerly winds in the morning will gradually transition to a westerly direction this afternoon. The Turnagain Arm wind should be largely absent for the first time in several days. && $$