Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 650 PM EDT Tue Apr 21 2020 Valid 12Z Sat Apr 25 2020 - 12Z Wed Apr 29 2020 ...Guidance/Predictability Assessment... A composite blend of reasonably well clustered guidance from the 12Z ECMWF/GFS produced a good forecast starting point Sat-Sun in a pattern with average predictability. After Sun, the 12Z GFS does not seem as well aligned with the ensemble consensus, particularly with respect to a compact but deep arctic upper low it drops southward across western Alaska (where other guidance keeps the energy farther north). Increased the ensemble mean weightings at longer time frames consistent with growing forecast spread and uncertainty. This forecast maintains good WPC continuity. ...Weather/Threats Highlights... A leading low/frontal system along with an enhanced area of winds/waves/precipitation remains slated for the Gulf of Alaska into early Saturday, before exiting over the Southeast Panhandle. Meanwhile upstream, at least two additional emerging frontal systems with deepening lows and enhanced winds/waves/precipitation will rotate over the Gulf of Alaska to off Southeast and Southern Alaska through early next week on the heels of the lead system. By next Tue-Wed, a deepening low is forecast to enter the western Bering Sea, with the associated frontal system crossing the Aleutians with increasing potential for precipitation and winds. Farther inland over the state, a couple arctic mid-upper level troughs/impulses will work over the North Slope and the Interior over the coming week, significantly cooling the recent warm spell. A few focused areas of snow showers are possible with the passing mid/upper-level waves, but the air mass will be quite dry, not supporting much in the way of widespread precipitation. Ryan 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 Hazards: - Much below normal temperatures across portions of mainland Alaska, Fri-Sun, Apr 24-Apr 26. 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