Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 652 PM EST Mon Nov 18 2019 Valid 12Z Fri Nov 22 2019 - 12Z Tue Nov 26 2019 The forecast period begins on Friday with a large low pressure system centered over the western half of Alaska, and weakening going into the weekend with a fast moving low crossing the northern Gulf of Alaska through Saturday. The models and ensemble means appear to resolve this initial pattern well with some timing differences of individual shortwave perturbations pivoting around the main low, so a majority blend of the latest 12Z models (GFS/ECMWF/UKMET) was used which maintains good WPC continuity. This pattern will favor a rather unsettled period across the southern third of the state featuring heavy precipitation, along with high winds/waves for coastal regions, including the southeast Panhandle region. By Monday, a storm system begins gathering strength across the north-central Pacific and eventually enters the Gulf of Alaska by early next Tuesday. Models continue to struggle both with timing and intensity of this system with the 12Z GFS much stronger and a bit slower, while the ECMWF is notably weaker. The 12Z CMC is much farther south and displaced from the ensemble means, so the CMC was not favored. By the end of the forecast period next Tuesday, there is a broad model signal for a potentially powerful storm system emerging from eastern Russia and entering the Bering Sea. Given how far out in time this event is, the deterministic models show significant differences with timing and intensity of this low. Similar to the Gulf low, the ECMWF is weaker than the GFS, and the CMC is much stronger and farther north. For both of the systems discussed, a blend of the ensemble means (12z GEFS and 00z ECENS) was used for days 7-8. The ECMWF also made up a small portion of the blend for days 7-8 to add a bit of definition given that it was the deterministic model that most closely resembled the mean pattern. Hamrick 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