Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 756 PM EDT Fri May 20 2022 Valid 12Z Tue May 24 2022 - 12Z Sat May 28 2022 ...Overview... The pattern over Alaska through the medium range period will generally consist of an upper high over the Bering Sea with its influence extending east into the mainland, in between a train of lows south of the state and an upper low initially inside the Arctic Circle but slowly sinking south through the latter part of next week. Generally light precipitation is forecast in this pattern, with modest amounts over the Panhandle. ...Guidance/Predictability Assessment... Model guidance remains in generally good agreement with the fairly slowly evolving pattern described above, especially with the blocky ridge across the Bering Sea to the mainland. Some differences persist with the movement/reorientation of the northern upper low--while guidance agrees on some southern meandering, GFS runs remain the farthest north while the ECMWF and CMC extend farther south, but oriented differently. A similar issue is seen with the associated surface lows, which affects frontal timing and extent across northern Alaska. The forecast today continued with conservative height decreases across the northern mainland. Meanwhile, individual and surface lows in the North Pacific south of the state exhibit some considerable differences within the troughy pattern. One main difference is that the GFS/GEFS phase energy together more than other solutions, leading to one stronger surface low south of the eastern Aleutians/Alaska Peninsula around Wed-Thu, while the ECMWF/CMC remain more split with the surface/upper lows. The solutions tend to converge a bit by the end of the week. The WPC forecast was based on a blend of deterministic guidance led by the 12Z GFS and ECWMF early, gradually adding in the influence of the GEFS and EC means as the period progressed. The means inclusion and the blending process served to minimize influences of any individual model, without a good reason to lean toward a certain model or camp at this point. ...Weather and Hazard Highlights... Generally light precipitation is forecast for Alaska through next week, both for the southern part of the state (with some enhancement possible in the Panhandle due to low systems) and some showers farther north near a frontal system coming through northern to central Alaska. River flooding may continue to be an issue over some locations in the middle latitudes of the mainland through at least the first part of next week, due to snow melt and ice jams. Periods of slightly warmer than normal temperatures are expected for the western mainland into the central part of the state under the upper ridge influence. The Panhandle and the southern coast, along with the North Slope, should see cooler than normal highs while lows should be nearer to normal. Tate Hazards: - Flooding likely across portions of mainland Alaska, Mon-Tue, May 23-May 24. 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