Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 707 PM EDT Mon Mar 30 2020 Valid 12Z Fri Apr 03 2020 - 12Z Tue Apr 07 2020 A relatively progressive weather pattern appears likely across Alaska and the North Pacific during the extended forecast period. A strong upper-level jet along the northern periphery of a building upper-level ridge axis near the date line and along the southern periphery of a broad region of cyclonic flow across eastern Siberia will result in an increasingly active storm track across the Bering Sea. Ensembles show general agreement that this relatively progressive flow regime should persist across Alaska and the Bering Sea through the extended forecast period (and beyond), with relatively strong shortwaves traversing the North Pacific jet spaced 2-3 days apart. A leading frontal system should bring precipitation and gusty winds to portions of southern mainland Alaska and the Alaska Panhandle on Fri (day 4). Deterministic solutions showed quite a bit of variability and inconsistency throughout the extended forecast period, making it difficult to prefer a single model solution for the forecast across Alaska and surrounding waters. A blend of the ECMWF/UKMET along with the ECENS/GEFS ensemble means represented a reasonable consensus during days 4-5, as a deep low pressure system moves across the western/central Bering Sea. After that, deterministic spread becomes quite large, by Sun (day 6) as the weakening low pressure system crosses mainland Alaska, and a new low develops farther south across the northern Gulf of Alaska on Mon (day 7). This system appears likely to bring a period of relatively widespread precipitation to mainland Alaska Sun-Mon, with some potential for gusty winds along the Bering Sea coast. By Mon and into Tue, as the low develops in the Gulf, expect precipitation to increase across the Alaska Panhandle. Given the increased guidance spread during days 6-8, a majority ensemble blend (ECENS/GEFS ensemble means) was used during that time frame. Ensemble means showed much better overall consensus than did deterministic solutions. Ryan Hazards: - Heavy precipitation across portions of mainland Alaska, Thu, Apr 2. - Much above normal temperatures across portions of mainland Alaska, Thu-Fri, Apr 2-Apr 3. 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