Alaska Extended Forecast Discussion National Weather Service College Park MD 637 PM EDT Fri Aug 29 2025 Valid 12Z Tue 02 Sep 2025 - 12Z Sat 06 Sep 2025 ...Into Early September Heavy Rain/Flooding/Wind Threats for Southwest/Western Alaska... ...Guidance Evaluation/Preferences... Favor a composite of best clustered guidance of the 12 UTC GFS/ECMWF models and GEFS/ECMWF ensemble means through medium- range time scales in pesky active flow with overall above average predictability. This plan best maintains WPC product continuity. ...Weather/Hazards Highlights... An amplified/blocky and slow to transition flow pattern over Alaska and vicinity will be highlighted by a series of potent shortwaves/surface low pressure systems primed to work through a Bering Sea/Aleutians mean upper trough to lift up into the Mainland around the periphery of Southeast Alaska to the eastern Interior mean upper ridge. This pattern will remain favorable to produce a protracted period of wet/unsettled weather expected to persist from the extended holiday weekend through much of next week. This will include a series of organized systems and long fetch atmosheric river moisture to fuel periodic and repeat chances for heavy rain/flooding and enhanced/gusty winds from the Alaska Peninsula through the Southwest/Western Alaska and up to the west-central Brooks Range where enhanced snows are also expected. Coastal flooding and overall inland wind threat will be maximized up through Southwest/Western Alaska over the holiday weekend. Meanwhile, Southeast Alaska should enjoy a pleasant week ahead overall as an upper ridge yields continued low rainfall chances and mainly benign weather as a compact closed low lifts well offshore with modest affect over the eastern Gulf of Alaska. Schichtel 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