Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 722 PM EDT Mon Mar 20 2023 Valid 12Z Fri Mar 24 2023 - 12Z Tue Mar 28 2023 ...Overview/Guidance Evaluation/Predictability Assessment... A broad upper trough will be situated over northwestern Alaska for the end of the week, and shortwave energy pivoting around the southern periphery of this trough will support a relatively weak surface low over the eastern Gulf that should be drifting southeast through Saturday. Another well organized low pressure system is forecast to make weather headlines going into the weekend as it approaches the western Bering and eastern Siberia as an upper level trough becomes amplified over this region, and a downstream upper ridge will likely be in place across eastern mainland Alaska and western Canada for Sunday into Monday. The model guidance initially has a good overall depiction of the synoptic scale pattern, so a multi-deterministic model blend sufficed as a starting point in the forecast process for the end of the week and into early Saturday. The CMC is a bit farther west with the track of the Bering low across eastern Siberia compared to the model consensus later on Saturday and into Sunday. The GFS becomes stronger with a trailing low across the Aleutians by Sunday and stronger with the downstream ridge axis across the Gulf and eastern Alaska. More of the ensemble means were incorporated into the forecast for the Sunday to Tuesday time period to account for increasing model differences. ...Weather/Hazard Highlights... Some coastal rain and mountain snow will likely be ongoing from the northern Gulf low late in the week, although the heaviest precipitation is likely to be over by that time. However, the main weather story is expected to be the increase in snow and wind associated with the approach of the next Bering Sea low pressure system over the weekend. Heavy snow is likely for western portions of the Brooks Range where 1 to 2 feet of snowfall accumulation is possible from Saturday night to early Monday. Heavy snow is also increasingly likely for southern portions of the Seward Peninsula where greater than a foot of heavy wet snow is possible as well. High wind gusts on the order of 40 to 60 mph will be possible across coastal portions of western Alaska as a strong pressure gradient develops, and some coastal flooding may also be a problem. In terms of temperatures, expect readings to generally be running 10 to 25 degrees above late March averages for central and northern portions of the state for the weekend as deep southerly flow ahead of the Bering Sea low advects a much warmer maritime air mass across the Interior, with the potential for many inland areas reaching highs above freezing on Sunday, even including areas north of the Brooks Range. A return to more seasonal March conditions is likely by early next week as a cold front crosses most of the state. Hamrick Hazards: - High winds across portions of western mainland Alaska and the Aleutians, Sat, Mar 25. - Heavy snow across portions of western mainland Alaska, Sat-Sun, Mar 25-Mar 26. 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