Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 516 PM EST Sun Nov 15 2020 Valid 12Z Thu Nov 19 2020 - 12Z Mon Nov 23 2020 ...Stormy Pattern for the Bering Sea and Gulf of Alaska... ...Guidance/Predictability Assessment... The WPC Alaskan medium range product suite was primarily derived from a composite blend of the quite compatible 12 UTC GFS/ECMWF/Canadian, 12 UTC GEFS/ECMWF ensemble means and 19 UTC National Blend of Models days 4/5 (Thu/Fri) in a pattern with above average system predictability. Opted for a still compatible ensemble mean and National Blend of Models composite blend days 6-8 amid growing forecast uncertainty, but again manually adjusted offshore lows deeper consistent with favorable upper support and model trends. ...Weather/Threats Highlights... Upper ridging over the Interior/North Slope will moderate temperatures significantly mid-later week in a mainly benign pattern. Meanwhile, cooling lead upper troughing lingering underneath over the far eastern Gulf of Alaska and Southeast Panhandle will slowly lose influence over the area Thursday. Upstream, there remains a strong guidance signal supporting amplified upper trough/closed low developments into the Bering Sea and Aleutians mid-later week, then again next Sun/Mon. These will offer several significant threats for deep offshore storms to focus enhanced winds/waves and precipitation across the region. Downstream energy transfer later week through early next week will also increasingly threaten southwest Alaska, southern Alaska, then southeast Alaska as ample upper trough/deepened storm energies work more in earnest across the Gulf of Alaska. 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 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