Area Forecast Discussion
Issued by NWS Anchorage, AK
Issued by NWS Anchorage, AK
442 FXAK68 PAFC 220035 AFDAFC Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 435 PM AKDT Sat Sep 21 2024 .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Tonight through Tuesday)... Conditions across Southcentral and the Gulf of Alaska remain mostly dry and clear this afternoon, although areas of cloud cover linger across the Copper River Basin. Active weather ramps back up again on Sunday morning when a front reaches Kodiak Island and the western Gulf. Steady precipitation and increased winds with the front will spread across the rest of the Gulf and Southcentral coast through Sunday. Northeasterly winds up to storm force are expected across portions of the northern Gulf Sunday evening and overnight. The low itself enters the western Gulf early Monday morning and tracks into the northern Gulf where it is expected to linger through mid week. Most of the precipitation with this system will be focused along the north Gulf coast for Sunday, although some precipitation will spread north to portions of interior Southcentral on Monday and Tuesday. Wind strength and precipitation intensity generally start to decrease heading into mid week as the system gradually weakens. && .SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days 1 through 3)... A deep occluded low will continue to be the focus for the forecast as it tracks along the Aleutians and into the Alaska Peninsula through late Sunday. Showery conditions as well as small craft to gale force easterly winds will clip the Central and Eastern Aleutians tonight and tomorrow as the chain sits immediately north of the low`s progress. Conditions further east and across Southwest Alaska will remain cool and dry through at least Saturday night. By Sunday morning, however, an occluded front will reach the Western Alaska Range with some precipitation expected for the AKPEN on Sunday. Models have trended slightly south with the track of the low, which may allow the rest of Southwest Alaska to maintain dry conditions into Monday while the low and its associated front shift into the Gulf. Behind and north of the low, persistent northerly flow is forecast to develop through the eastern Bering. The rest of the forecast will entail the southward movement of a cooler airmass across Southwest Alaska and into the Eastern Aleutians. Portions of the Kuskokwim Delta and Lower Kuskokwim Valley will flirt with freezing overnight low temperatures Monday and Tuesday night, though precipitation chances will remain minimal. && .LONG TERM FORECAST (Days 4 through 7: Wednesday through Saturday)... The long-term pattern across the area generally looks to be characterized by a longwave trough over the Bering with numerous shortwaves rotating around the base of the trough and lifting into the Gulf of Alaska and into Southcentral Alaska. The result will be unsettled weather; especially across the North Gulf Coast where most precipitation looks to fall for Wednesday into Thursday as a surface low in the Gulf throws moisture northward. This low weakens a slides to the southeast Thursday evening as additional weak shortwaves lift across the area helping to keep light shower chances going through Friday. A shortwave drops out of Eastern Russia Thursday night and helps to re-energize the Bering trough for Friday. The associated surface low moves from northwestern Bering Sea Wednesday to the southeastern Bering by Friday. This system looks to bring cold air down from Russia and across the Bering on its journey from north to south. Scattered showers and windy conditions are anticipated across the Aleutian Chain and Pribilof Islands with steadier rain along the Southwestern coast. The front then looks to enter the western Gulf of Alaska by Saturday delivering another round of rain likely to Kodiak Island, the Eastern Kenai Peninsula, as well as Prince William Sound. There is still a lot of uncertainty with how far rain could make it inland with this system. And, with likely southeasterly flow aloft, rain would be light. The pattern will become favorable for cyclogenesis to occur in the North Pacific on Saturday as the cold air driving southward from the Bering interacts with warm air from the sub-tropical jet. While a storm system does look to form, confidence is very low on exactly where in the North Pacific it will form, where it will track, and how fast the system will strengthen. && .AVIATION... PANC...VFR conditions and light winds will persist. A strong occluded front will lift northward across the Gulf Sunday which will lead to increasing winds across the Kenai and Chugach Mountains. However, strong down-Inlet pressure gradients will keep these winds away from the terminal. && $$