Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 635 PM EDT Fri Mar 13 2020 Valid 12Z Tue Mar 17 2020 - 12Z Sat Mar 21 2020 ...Overview and Guidance/Predictability Assessment... A series of potentially powerful Pacific systems will lift through a highly unsettled Aleutians and Bering Sea and tend to work inland into the Interior/North Slope then Arctic Ocean, breaking through a lead upper level mean ridge position. There is potential for the development of quite deep lows with well organized frontal structures that would focus winds and widespread and enhanced/widespread precipitation. Temperatures will warm across the Interior/North Slope next week, but remain cold enough to support widespread heavy snows, with a particular risk for northwest Alaska with strongest low approach and shearing over the region later next week. Meanwhile underneath, additional system trough/jet energies will break eastward through the southern portion of a lead main upper ridge position next week over the Gulf of Alaska in a pattern with more modest precipitation potential for southwest/southern/southeast Alaska. ...Weather Highlights/Threats... The WPC Alaskan medium range product suite valid Tuesday-Thursday was mainly derived from a composite blend of reasonably well clustered guidance from the 12 UTC GFS/ECMWF, GEFS/NAEFS/ECMWF ensemble means and the 19 UTC National Blend of Models (NBM). Forecast continuity and predictability seem above normal during this period. Forecast spread increases with embedded systems in the 7/8 day timeframe, so it seems prudent to rely on more consistent and seemingly reasonable GFS/NAEFS and ECMWF ensemble mean guidance and the NBM at these longer time frames along with manual edits to depict system strength/integrity consistent with near average predictability. Schichtel 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 precipitation across portions of the Alaska Peninsula, Mon, Mar 16. - Heavy precipitation across portions of the coastal sections of southern Alaska, Tue, Mar 17. - Heavy snow across portions of northwestern Alaska, Thu-Fri, Mar 19-Mar 20. - High winds across much of western and northwestern Alaska, Wed-Fri, Mar 18-Mar 20. - High winds across the Aleutians, Tue-Wed, Mar 17-Mar 18. - Much above normal temperatures across much of western and northern Alaska, Mon-Fri, Mar 16-Mar 20. 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