Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 526 PM EDT Wed Mar 18 2020 Valid 12Z Sun Mar 22 2020 - 12Z Thu Mar 26 2020 ...Overview and Guidance/Predictability Assessment... In the wake of a departing Bering Sea system late in the week, the latter portions of the weekend into early next week is likely to feature upper level ridging and surface high pressure, especially across southern Alaska. A fast moving storm system across northern mainland will bring widespread high chances of precipitation. By Day 7-8 (Wed-Thu), model guidance trends toward more troughing as a shortwave approaches the western mainland with the approach of a deeper surface low that is just beyond the current forecast period. ...Weather Highlights/Threats... Model agreement was average to slightly above average for days 4-5 where an equal blend of the deterministic guidance was used (12Z ECMWF/GFS/UKMET/CMC). Beyond that time frame, the latest ECMWF/CMC showed better run to run consistency while the 12Z GFS seemed to be racing ahead of the ensemble means somewhat. Thus, considerably less GFS was used for day 6-8 with increasing weights of the ECENS ensemble mean each day through day 8. This should help mitigate the less predictable small scale variances later in the forecast period while maintaining some WPC forecast continuity. Taylor 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: - Heavy snow across portions of mainland Alaska, Sat, Mar 21 and Mon-Tue, Mar 23-Mar 24. - Much above normal temperatures across portions of mainland Alaska, Sat-Tue, Mar 21-Mar 24. 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