Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 605 PM EDT Mon Apr 17 2023 Valid 12Z Fri Apr 21 2023 - 12Z Tue Apr 25 2023 ...Easing cold pattern to return this weekend... ...Guidance Evaluation/Predictability Assessment... Dominant closed upper high settlement near the Bering Strait/Chukchi Sea and overall blocky pattern for this forecast period for Alaska and vicinity is well shown in guidance, but now with more surrounding system differences, especially over the Gulf of Alaska through Days 4-8. Prefer a composite of reasonably compatible 12 UTC GEFS/ECMWF ensemble means for maximum WPC product continuity amid growing uncertainties. This solution was collaborated with local Alaskan forecast offices. One caveat is that the pattern prove slower to breakdown early next week than recent models and ensembles indicate considering historical guidance bias with established blocks. ...Overview and Weather/Hazard Highlights... Amplified upper ridging now to the west of the state will reform into a strong closed upper near the Bering Strait/Chukchi Sea to anchor establishment and persistence of a large scale Omega-style blocking pattern over the state and broad vicinity as upper troughs/closed low increasingly become solidified all around the powerhouse closed upper high. Short term height rises over the mainland will accompany a temporary easing of an ongoing cold pattern into later this week. However, there is a strong signal for a renewed cooling upper trough to dig southward down through the mainland by the weekend that will linger into the last week of April. The North Slope and Interior then South-central to northern Southeast Alaska should steadily become colder and unsettled again in this pattern. Farther south, there is a risk of deeper than expected Gulf of Alaska low developments to monitor given potentially potent, but quite uncertain energy interactions within a mean upper trough position held over the area. Periods of light to locally moderate precipitation will mainly be limited to Southeast Alaska. There is potential there for enhancement from next weekend into next week if a recent northward trend of guidance leads to a closer proximity of any of the uncertain Gulf of Alaska lows. Schichtel Hazards: - Much below normal temperatures across portions of central, eastern, as well as interior southern mainland Alaska, Sun-Mon, Apr 23-Apr 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