Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 712 PM EDT Mon Oct 17 2022 Valid 12Z Fri Oct 21 2022 - 12Z Tue Oct 25 2022 ...Southeast Alaska heavy precipitation threat into Friday... ...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... The 12 UTC GFS/ECMWF/Canadian model solutions seem well clustered for Friday and are well supported by ensembles in a pattern with above normal predictability. In this period, low energies will keep from the northern Bering Sea and Western/Southwest Alaska into the Interior unsettled with periods of wintry precipitation and some gusty winds/coastal surf. This includes influence from Arctic stream upper trough/low energies lingering near the North Slope. A lingering mean upper trough from the northern Bering Sea back into Northeast Russia will act to hold onto this active pattern over the weekend into next week, but offers a less certain daily embedded weather system focus. The compatible and better run to run consistent 12 UTC GEFS/NAEFS/ECMWF ensemble means 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. Meanwhile, northern Gulf of Alaska low genesis and a potent trailing front set to work eastward across the Gulf of Alaska into Friday will focus a maritime threat along with wrapping/frontal inflow into Southeast Alaska into Friday. The 12 UTC GFS/ECMWF/UKMET/Canadian now offer a well clustered solution for this period, bolstering forecast confidence. Upstream, forecast spread increases 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. The 12 UTC GEFS/NAEFS/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. The earlier 00 UTC ECMWF and now the newer 18 UTC GFS trended toward this preferred and collaborated solution that offers an emerging maritime/precipitation/wind threat from the Aleutians, the Alaskan Peninsula, Kodiak Island to South-central and Southeast Alaska. Schichtel Hazards: - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Thu-Fri, Oct 20-Oct 21. - High winds across portions of mainland Alaska, Thu-Sat, Oct 20-Oct 22. 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