Alaska Extended Forecast Discussion National Weather Service College Park MD 658 PM EDT Tue Aug 26 2025 Valid 12Z Sat 30 Aug 2025 - 12Z Wed 03 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, although there are some greater differences over the Arctic Ocean and northwestern Canada. With respect to the large Bering Sea low, the ECMWF is generally faster in lifting the low to the northeast, whereas the GFS/GEFS are slower. Going into early next week, the upper ridge/surface high over the Gulf has the best overall model agreement. There is some signal in the guidance for another low pressure system to develop south of the Aleutians about a week out, with the AIFS guidance stronger with this by next Wednesday as it lifts towards the north, so this will continue to be monitored in future forecasts. The ensemble means were gradually increased to about half by next Wednesday. ...Weather/Hazards Highlights... A well organized low pressure system affecting southern Alaska through the end of this week is expected to weaken and lift north by Saturday. Attention then turns to the next big weather maker developing over the Bering Sea that 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. Coastal flooding is also possible for areas near Bristol Bay and the Yukon Delta. 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