Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 617 PM EST Tue Nov 17 2020 Valid 12Z Sat Nov 21 2020 - 12Z Wed Nov 25 2020 ...Overview and Guidance/Predictability Assessment... Active pattern across the high latitudes this weekend into next week as an upper high near far northeastern Alaska splits WNW-ESE. This favors continued/reinforced troughing across the Bering into the Gulf via several systems. Lead system will translate through the Gulf (old parent low in the Bering) early Saturday and into the Panhandle. Next system will follow behind, astride the Aleutians and into the Gulf by early Monday. Last system will move into the western Bering next Tuesday and toward the AKPen around next Wednesday. The 12Z models/ensembles were in decent agreement to start with the first system, though the GFS/UKMET were a bit different than the ECMWF/Canadian. Favored the ECMWF-led consensus nearer to the ensemble means. For the 2nd system (Sun-Mon), GFS appeared too quick given the slower trend overall, so favored the ECMWF/Canadian/UKMET which were displaced just a bit south of the slower ensemble means. This would keep that surface low a bit farther off the coast, perhaps with greater affect to the Panhandle late Monday. For the final system in the Bering next Tuesday, models were spread in each direction so trended completely to the ensemble means as a course of least regret. To the north, upper ridging will give way to lower heights with time in weak southeasterly mid-level flow. ...Weather/Threats Highlights... Focus for heavier precipitation will lie along southern coastal areas into the Panhandle every 1-2 days or so with each system. Given the slightly different approaches for each system, appears that the precipitation could be spatially spread out. First system will bring windy conditions and heavy rain/snow to coastal Southcentral into the Panhandle, followed by the second system Monday that may shift that axis to the central/southern Panhandle as the triple point may head toward Haida Gwaii. Last system may have a less favorable moisture source connection, but still could spread some modest rain to the Aleutians next week. Fracasso Hazards: - Heavy precipitation across portions of mainland Alaska and the Aleutians, Sat, Nov 21. - High winds across portions of mainland Alaska and the Aleutians, Fri-Sat, Nov 20-Nov 21. 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