Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 524 PM EST Tue Dec 22 2020 Valid 12Z Sat Dec 26 2020 - 12Z Wed Dec 30 2020 ...Guidance and Uncertainty Assessment... For the forecast period, global deterministic and ensemble guidance shows relatively good agreement and consistency from the previous cycle. A intense and large cyclone is expected to track across the Aleutians into the Bering Sea this weekend. This system shows very good agreement in the 12Z guidance (ECMWF/GFS/CMC/UKMET) with respect to its depth and location. As that system weakens and occludes, several additional shortwaves will track in the fast flow underneath it where the deterministic models show timing and strength differences to various waves of low pressure. By this point, the WPC blend used an increasing amount of the ECENS/GEFS to dampen out the uncertainty and to keep some component of continuity in the day 6-8 period. ...Weather/Hazards Highlights... The aforementioned large scale cyclone is forecast to intensify and track toward the Aleutians, where gale to storm force winds and periods of heavy precipitation may be possible through the Christmas holiday weekend. The system should slowly weaken early next week as it spreads moderate precipitation across the Alaska Peninsula. Across mainland Alaska, milder than average temperatures will prevail through the weekend before gradually cooling down to near normal levels for both the northern and southern portions of the state. Taylor 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