Alaska Extended Forecast Discussion National Weather Service College Park MD 633 PM EDT Mon Aug 25 2025 Valid 12Z Fri 29 Aug 2025 - 12Z Tue 02 Sep 2025 ...Multi-Storm Heavy Rain/Flooding/Wind threats for Alaska fueled by Atmospheric Rivers... ...Guidance Evaluation/Preferences... 12 UTC GFS/ECMWF/UKMET/Canadian models and GEFS/ECMWF/Canadian ensemble solutions now seem reasonably well clustered through medium range time scales, bolstering forecast confidence in quite the stormy pattern. Favor a composite trending blend weightings increasingly toward the ensemble means over time as consistent with predictability. WPC product continuity is well maintained. ...Weather/Hazards Highlights... A moisture pooling frontal system and amplified/supporting upper trough will work eastward and inland over the mainland Friday into Saturday to temporarily dampen ambient short range upper ridging while sweeping unsettled conditions/organized rainfall across the broad region. There will meanwhile be a lingering heavy rain focus into SouthCentral Alaska with undercutting low energies, especially with favored terrain, as fueled by the final vestiges of a short range primed atmospheric river with tropical West Pacific connections. The upper ridge should build back over the Interior in the wake of system passage later weekend. Upstream...there remains a strong signal to highlight development and track of a deep storm across the Aleutians to the Bering Sea Friday and the weekend to produce wrapping high winds/waves and heavy rain threats given another long fetch moisture connection. This protracted maritime threat will also work steadily downstream to support another round of impactful weather by later in the holiday weekend to include a wind/rain threat for West/Southwest Alaska as well as with northern Gulf of Alaska triple-point low formation to affect the Alaska Peninsula/Kodiak Island and SouthCentral Alaska into early next week. 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