Alaska Extended Forecast Discussion National Weather Service College Park MD 647 PM EDT Wed Aug 27 2025 Valid 12Z Sun 31 Aug 2025 - 12Z Thu 4 Sep 2025 ***Strong Bering Sea storm system expected to bring heavy rain and gusty winds to portions of western Alaska this weekend*** ...Guidance Evaluation/Preferences... The 12Z model guidance suite features good synoptic scale agreement across mainland Alaska and adjacent maritime areas for the weekend, with a general deterministic model blend sufficing as a starting point. With respect to the large Bering Sea low, the overall trend compared to yesterday has been about 100-200 miles southwest, and thus a slightly slower passage is now more likely. There is some signal in the guidance for another low pressure system to develop south of the Aleutians about a week out, but it does not appear to be as strong as yesterday's guidance depicted. Model spread increases substantially by next Wednesday and Thursday as the overall ridge tries to break down over the North Pacific. The ensemble means were gradually increased to about 50-60% by the end of the forecast period. ...Weather/Hazards Highlights... The next big weather maker developing over the Bering Sea this weekend will initially affect the Aleutians starting on Saturday with heavy rain and strong winds, and then this reaches western mainland Alaska going into Sunday and Monday. This will be accompanied by strong southerly flow that will advect deeper moisture northward and bring periods of moderate to locally heavy rainfall from the Alaska Peninsula to the western Brooks Range and the Seward Peninsula. Coastal flooding is also possible for areas near Bristol Bay and the Yukon Delta, but the overall inland wind threat is less compared to yesterday's forecast, so the wind hazard area is now confined more to the southwestern coastal areas. In addition, this storm system is forecast to bring a warming trend to much of the state early next week after a cooler weather pattern this weekend. Meanwhile, southeast Alaska should enjoy a pleasant week ahead overall as the upper ridge results in low rainfall chances and more sunny conditions. 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