Alaska Extended Forecast Discussion National Weather Service College Park MD 559 PM EDT Sun Aug 31 2025 Valid 12Z Thu 04 Sep 2025 - 12Z Mon 08 Sep 2025 ...Heavy Rain/Flooding/Wind threat pattern with repeat focus over Southwest/Western into Southern Alaska to persist this week... ...Guidance Evaluation/Preferences... Favor a 12 UTC GEFS/ECMWF/Canadian ensemble means composite solution through these medium-range time scales to best maintain WPC product continuity. This is despite slowly but steadily growing system timing and strength variances in the models, albeit within an overall well supported larger scale pattern evolution that should remain favorable for repeat stormy and unsettled flow. ...Weather/Hazards Highlights... The threat pattern over Alaska and vicinity will be highlighted by a series of wet/potent surface low pressure systems primed to work from a Bering Sea/Aleutians mean upper trough position to lift up into the Mainland around the periphery of an amplified Southeast Alaska to the eastern Interior mean upper ridge position. This pattern will remain favorable to produce a protracted period of wet/unsettled weather expected to persist from the extend through much of the upcoming week. This will include a continued significant series of organized systems and long fetch atmosheric river moisture to fuel periodic and repeat chances for heavy rain and continued runoff/flooding isues with focus from the Alaska Peninsula through the Southwest/Western Alaska and up to the west- central Brooks Range where enhanced snows are also expected. By this period, a main lead lows to focus activity is expected to lift from the Alaska Peninsula and southeast Bristol Bay midweek prior to shearing through the Mainland later week. Upstream, a deeper storm track is meanwhile slated to bring high winds/unsettled flow and maritime threats across the Aleutians and nearby waters. Along with maritime hazards entering the southern Bering Sea/Bristol Bay and western Gulf of Alaska, this storm and potential triple-point low development may focus subsequent high wind and heavy rainfall threat impacts with downstream energy translation into Southwest/Western Alaska along with the Alaskan Peninsula/Kodiak Island this week. Activity should also then affect coastal SouthCentral Alaska by next weekend and eventually finally bring increasing rain chances back to Southeast Alaska after quite a pleasant week of continued late summer weather. 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