Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 756 PM EDT Tue Oct 18 2022 Valid 12Z Sat Oct 22 2022 - 12Z Wed Oct 26 2022 ...Emerging storm threat from the Aleutians Friday through the Gulf of Alaska/coastal communities this weekend... ...Active pattern from Bering Sea Lows into Western Alaska through the period... ...Overview and Guidance/Predictability Assessment and Weather/Hazards Highlights... A mean trough/upper low will be in place over the Bering Sea back to northeast Russia with multiple impulses near the North Slope during this period which will largely keep the region in an active pattern. Much of West/Southern Alaska and portions of the Interior will be unsettled during the course of the extended forecast as multiple energy impulses track through the flow ushering in gusty winds, coastal surf and wintry precipitation. Although this synoptic pattern has above average predictability, it does decrease confidence on specifics with each individual system as it tracks through the region. The 12Z deterministic guidance from the ECWMF, GFS, CMC (UKMET at least initially) are fairly clustered with the surface low near the AK Pen that tracks toward the southern/Southeast. From then on there is increasing spread with the next couple of systems entering in from the North Pacific and Bering Sea. Some of the energy from TD 24W and 92W in the western Pacific will be absorbed into the flow which also increases the spread. Similar to previous runs, 12Z GEFS, NAEFS and ECMWF ensemble means continue to have above average predictability and seem to provide a good forecast starting point for these longer time frames, albeit with less detail consistent with growing uncertainty. There is an emerging guidance signal to allow development of a more consolidated Bering Sea maritime low early next week to monitor. Upstream, forecast spread continues to increase dramatically with the 12 UTC Canadian/UKMET offering a more phased solution lending development of a much deeper new storm along/south of the Aleutians Friday to across the Gulf of Alaska this weekend compared to the weaker and more offshore 12 UTC GFS/ECMWF. Utilizing a heavy weighting of the 12Z GEFS, NAEFS and the ECMWF ensemble means offer a compromise track offshore and manual modifications were then applied to that composite to decently deepen the low more than WPC continuity given potential in an energetic flow stream. Campbell/Schichtel Hazards: - High winds across portions of the Aleutians, Mon-Tue, Oct 24-Oct 25. 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