Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 708 PM EDT Wed Apr 13 2022 Valid 12Z Sun Apr 17 2022 - 12Z Thu Apr 21 2022 ...Deep cyclone transitions from western Pacific Typhoon Malakas forecast to affect the Aleutians Sunday-Tuesday... ...Pattern and Weather/Hazard Highlights... A deep cyclone originates from Typhoon Malakas currently located in the western Pacific is forecast to approach the Aleutians for the beginning of next week. Wrapping rains driven by high winds associated with the significant storm will also offer a widespread maritime threat. Otherwise, an upper level ridge axis should remain in place across much of mainland Alaska, with a surface high settling north of the Arctic Coast. However, a weak undercutting upper low will likely track westward across the Interior this weekend and then meander over the Bering Sea. Meanwhile, a strong low pressure system over the Bering Sea should weaken by the weekend. In this pattern, much of the state should begin the period with temperatures generally near to above average, and then colder weather arrives in time for the weekend for eastern areas of the state as cold air moves in from western Canada. Milder conditions should continue into early next week for northern Alaska near a closed upper high and over the southwestern mainland with deep Aleutian system affect. In terms of precipitation, most of the Interior region should remain dry and any periods of rain and mountain snow will likely be modest for southern and southeast Alaska as storm systems spin well offshore. ...Guidance/Predictability Assessment... Pretty much the only system of concern continues to be the extratropical counterpart of Typhoon Malakas forecast to move near/through the Aleutians early next week. Model QPF and cyclone depth had backed off in earlier runs today (especially the GFS). However, the 12Z ECMWF and CMC went with a stronger cyclone and more northerly track in a similar fashion as yesterday's GFS. A composite blend of 40% from the 06Z GFS/12Z GFS/12Z GEFS, 40% from the 12Z ECMWF/12Z EC mean and 20% from the 12Z Canadian/CMC mean yielded solutions that are quite compatible with WPC continuity. It should offer some system details to the impending cyclone and also to most other features evident over the rest of Alaska in a pattern with near average predictability. By Days 6-8, the blend transitions to mostly a consensus of the ensemble means, which should provide a decent starting point for the longer range forecasts. Kong/Schichtel Hazards: - Heavy precipitation across portions of mainland Alaska and the Aleutians, Tue, Apr 19. - Heavy precipitation across portions of the Aleutians, Sun-Mon, Apr 17-Apr 18. - High winds across portions of mainland Alaska and the Aleutians, Tue, Apr 19. - High winds across portions of the Aleutians, Sun-Mon, Apr 17-Apr 18. Additional 3-7 Day Hazard Information can be found on the WPC medium range hazards outlook 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