Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 725 PM EDT Sun Mar 22 2020 Valid 12Z Thu Mar 26 2020 - 12Z Mon Mar 30 2020 ...Turning colder for much of the Interior late next week... Upper pattern will turn toward much lower heights over the Interior of Alaska next weekend as upper ridging splits off through the Bering Sea. The evolution of an upper low south of Kamchatka has not been handled well at all the past couple of days, and this ties to both the upper ridge strength/shape and northern stream flow across far northeastern Russia. The end result still comes together from various avenues, but how the interim days sequence together remains hard to determine. The ECMWF ensemble mean has been least susceptible to run-to-run changes, mostly by definition, but at least provided a good baseline to the forecast. West of 180, the splitting upper low (perhaps now in three pieces and not two) may be slow enough to allow the ridge to its east to surge northward and pinch off over far northeastern Russia which would allow energy to shear eastward into southwestern Alaska as the western part of an upper low over the Canadian archipelago sinks southward. This would still bring a swath of modest snow to the Interior, focused from the Alaska Range northward, before it all pushes into the Gulf next week Sun/Mon. The 12Z GFS/Canadian/ECMWF had at least enough agreement to use in the blend for some detail with the ECMWF ensemble mean and 12Z NAEFS mean, maintaining an increasingly drier and colder flow over the Interior/North Slope. Back to the west by next weekend, flow looks increasingly westerly as the ensembles show strong upper ridging beneath troughing over Kamchatka and a strong jet (170kts?) near the western/central Aleutians. Fracasso 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