Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 617 PM EDT Fri Apr 15 2022 Valid 12Z Tue Apr 19 2022 - 12Z Sat Apr 23 2022 ...Deep cyclone transitioning from western Pacific Typhoon Malakas to affect the Aleutians early next week... ...Overview... The main focus of significant systems during next week will be near the Aleutians and over the northeastern Pacific, but storm activity should eventually focus more into the Gulf of Alaska. Deep low pressure originally associated with Typhoon Malakas should track over and then southeastward from the Aleutians early next week, bringing strong winds/enhanced precipitation and maritime threats. Another potentially strong system could track near the Aleutians later in the week. This system has lower confidence in the details, but the guidance signal has improved. Meanwhile an area of mean low pressure will likely exist south of the Panhandle for most of the period, with an initial system ultimately being replaced by a somewhat weakened form of the leading Aleutians storm. The combination of these features may bring some moisture northward into the Panhandle. Farther north, an upper ridge centered near the northern coast of the mainland should weaken somewhat but lingering ridging could persist into late week, while lower heights with troughing/one or more weak upper lows may prevail near the southern coast. ...Guidance/Predictability Assessment... A blend of decently clustered guidance from the 12 UTC GFS/ECMWF/UKMET/Canadian seems to provide a good forecast basis for days 4/5 (Tue/Wed). Forecast spread growth into longer time frames seems to favor increasingly incorporating 12 UTC GEFS/ECMWF ensemble means that stay compatible into days 7/8. Manual adjustments were applied to ensure sufficient depth for a later period offshore low that seems to have the good closed upper trough support off the Aleutians. Individual models and ensemble members are naturally more varied, but many now have some deep solutions and the 12 UTC GFS/ECMWF happen to share a similar depiction for day 7/next Friday. ...Weather/Hazard Highlights... The extratropical reflection of Typhoon Malakas tracking near the Aleutians Monday into Tuesday will produce a broad area of strong winds/maritime threats and precipitation from the Bering Sea through the North Pacific early next week. Another strong storm may track near the Aleutians next Thursday-Friday with associated enhanced winds and precipitation. This system should extend its influence to the Alaska Peninsula and eventually onward into next weekend with slowing downstream progression over the Gulf of Alaska under a mean upper low/trough. Relative to the first system, there is greater uncertainty with details of the late week system so continue to monitor latest forecasts for updated information. After Monday a couple surface systems to the south of the Panhandle may push moisture far enough north to bring precipitation to portions of the region. Confidence is fairly low for exact amounts/coverage, but most activity should be on the lighter side. Much of the mainland should be fairly dry with at most very light/scattered precipitation. In general expect above normal temperatures over most of the northwestern half of the mainland and below normal readings over the southeastern half of the mainland and the Panhandle. Some areas may see slightly warmer anomalies for morning lows relative to daytime highs. Schichtel Hazards: - Heavy precipitation for parts of mainland Alaska and the Aleutians, Thu-Fri, Apr 21-Apr 22. - Heavy precipitation across portions of the Aleutians, Mon, Apr 18 and Thu-Fri, Apr 21-Apr 22. - High winds across portions of mainland Alaska and the Aleutians, Thu-Fri, Apr 21-Apr 22. - High winds across portions of the Aleutians, Mon, Apr 18 and Thu-Fri, Apr 21-Apr 22. 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