Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 601 PM EDT Mon Mar 29 2021 Valid 12Z Fri Apr 02 2021 - 12Z Tue Apr 06 2021 ...Guidance/Uncertainty Assessment... The 12 UTC GFS/ECMWF solutions seem reasonably clustered and have decent ensemble support into day 4/Friday. Model solutions diverge quickly after that, still due to upstream sensitivities in both the amplitude evolution and stream interaction without a clear signal for any singular solution. Accordingly, a 12 UTC GFS/ECMWF and GEFS/ECMWF ensemble mean composite was used as a basis for the day 4/Friday forecast before quickly transitioning to a 50-50 composite of the GEFS/ECMWF ensemble means days 5-8 (Saturday-next Tuesday). The ensemble means are decently compatible considering the rapidly increasing forecast spread and maintain better WPC continuity than the models. ...Weather/Hazards Highlights... Lingering upper trough support over the Interior may favor unsettled and cooled weather to include some locally enhanced snows Friday. Meanwhile to the south, an amplified upper trough dug over the eastern Gulf of Alaska will support a lingering precipitation focus into the Panhandle. Upstream, an unsettling northern Bering Sea system Friday will progress into the mainland by the weekend. This should support some threat of enhanced snows from western and southwestern Alaska into the central mainland. There is additional but uncertain western Bering Sea system potential by early next week that could effect the Aleutians. These system energies may tend to dig to the lee of a mean upper ridge built up through the Aleutians. This pattern may favor periodic reinforcement of surface lows from the northern to eastern Gulf of Alaska that would offer a recurring threat for lead flow to fuel periods of moderate terrain enhancing precipitation for southeast Alaska. Schichtel Hazards: - Heavy snow across portions of mainland Alaska, Fri-Sat, Apr 2-Apr 3. Additional 3-7 Day Hazard information can be found on the WPC medium range hazards 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