Area Forecast Discussion
Issued by NWS Anchorage, AK
Issued by NWS Anchorage, AK
562 FXAK68 PAFC 221233 AFDAFC Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 433 AM AKDT Sun Sep 22 2024 .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Today through Tuesday night)... Clear skies overnight has led to numerous locations around Southcentral, including Soldotna, east Anchorage, and Glennallen, to drop into the 20s for low temperatures this morning. This will not be the case again tonight as the next weather system is moving rapidly toward Southcentral today. Expect increasing clouds for the entire region today with Kodiak starting to rain later this morning and that rain spreading to the north Gulf coast this afternoon into this evening. While this low will bring widespread Gale force winds to the Gulf, with some Storm force winds in the barrier jet that will develop overnight along the north Gulf coast, this low will rapidly weaken as it moves into the northern Gulf on Monday. However, it will be slow to leave the area, remaining quasi-stationary into Wednesday. That leaves the next few days with rain along the north Gulf coast the next few days and clouds inland. Cross barrier flow should cut off most of the rain from moving too far inland, but this flow will weaken and then probably allow more showers into inland areas Monday and Tuesday. The most challenging aspect of the forecast will be around Kodiak for Monday into Tuesday night. While the rain should shut off on Monday as the passing low puts Kodiak into northwest flow the uncertainty is whether the front wrapped around the weakening low will be able to edge westward enough to bring in more rain on Tuesday or Wednesday. Models are a real mixed bag with this as they appear to be struggling with what to do with the colder air filtering into the Gulf from Southwest Alaska on those days. At this point, have the keeping the main rain farther east of Kodiak, but it is worth looking into as this system moves through the area. && .SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days 1 through 3)... Our deep occluded low just south of the Alaska Peninsula will spend the next 24-hr working its way into the Gulf of Alaska. Gale force winds will spread along the front, pushing across the Alaska Peninsula and into the southeastern Bering Sea. Elevated winds will push along the backside of the low and produce gale force gusts through the gaps and passes of the southern AKPen and the Eastern Aleutians. Additionally, gales will push their way into Bristol Bay through the Kamishak Gap. Conditions across Southwest Alaska will remain cool and dry. The exception is, an occluded front will reach the Western Alaska Range with some precipitation expected for the AKPEN on today. As the front moves out through Monday morning, precipitation chances will diminish. 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. && .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 today 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. && $$