Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 756 PM EDT Sat May 21 2022 Valid 12Z Wed May 25 2022 - 12Z Sun May 29 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 with troughing possibly sinking south into the northern mainland through the latter part of next week. Generally light precipitation is forecast in this pattern, mostly over the southern half of the state but with occasional rain/snow showers in the north as well. ...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, models are inconsistent on the east-west placement of the centroid of the low and how far south branches of the associated troughing extend. After models were showing the opposite yesterday, GFS runs are now more aggressive with digging the northern stream trough into the state late next week than the ECMWF/CMC, so preferred a more conservative approach with the trough extent and frontal position. Meanwhile, individual and surface lows in the North Pacific south of the state exhibit some considerable differences within the troughy pattern. The ECMWF and GFS are showing somewhat closer solutions today while the UKMET and CMC have differences in phasing of the energy. In general the exact low tracks and individual 500mb lows are uncertain. 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 and decreasing weighting of the GFS. Thus favored the ECMWF in terms of the deterministic models, but not dramatically due to the means inclusion and the blending process. ...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 southern 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 far southeastern mainland will likely be cooler than normal, while the North Slope could see a mix of above and below normal temperatures. Tate 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