Alaska Extended Forecast Discussion National Weather Service College Park MD 747 PM EDT Sun Sep 14 2025 Valid 12Z Thu 18 Sep 2025 - 12Z Mon 22 Sep 2025 ***Heavy rain and gale force winds expected from the Kenai Peninsula to Southeast Alaska*** ...Guidance Evaluation/Preferences... The 12Z model guidance suite initially has a good overall depiction on the overall weather pattern across the domain, but mesoscale and timing differences increase especially across the north Pacific and the Gulf going forward into the weekend and next Monday. The tricky part of the forecast is triple low formation and how they interact with the main upper level low that will be situated over the northern Gulf. A general deterministic model blend suffices as a good starting point for Thursday. The ensemble means were gradually increased to about half by next Monday. ...Weather/Hazards Highlights... Expect a continued series of deepened low pressure systems late this week and into next weekend to bring high winds across the Aleutians/Southern Bering Sea, and then moderately impact Southwest Alaska and the Alaska Peninsula. Guidance signals are growing in support for the deepest moisture plumes to focus repeat periods of moderate to heavy rainfall and high winds from Kodiak Island to especially the Kenai Peninsula/South-Central Alaska and Southeast Alaska. Several inches of rainfall are likely from the Kenai Peninsula to Southeast Alaska as multiple surges of moisture move into the region, with the highest totals across the windward terrain from the St. Elias Mountains to near Sitka. Strong winds of gale force are likely for the near shore waters owing to enhancement of the coastal barrier jet for these same general areas, with the highest winds expected on the 18th. In terms of temperatures, a gradual cooling trend is expected to commence across the mainland as a polar front slowly sinks southward throughout the period. Hamrick Additional 3-7 Day Hazard Information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range Alaskan products including 500mb, surface fronts/pressures progs and sensible weather grids can also be found at: https://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif https://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml https://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html