Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 335 PM EST Sun Dec 05 2021 Valid 12Z Thu Dec 09 2021 - 12Z Mon Dec 13 2021 ...Another Major Storm for Alaska... ...Overview and Guidance Evaluation/Preferences and Weather/Hazard Highlights... Amplifying upper trough energies will support deep southern Bering Sea storm genesis into Thursday, with model guidance dropping low system pressure into the 950's mb. This system presents a significant maritime and Aleutian wind, wave and wrapping precipitation threat. The powerful storm is slated to slam into southwest Alaska, the Alaskan Peninsula, Kodiak Island and southern Alaska Thursday into Friday. Downstream translation and northern Gulf triple point low redevelopment Friday into next weekend will act to threaten the region with high winds and offshore waves along with heavy precipitation onward into southeast Alaska through next weekend. 12 UTC GFS/ECMWF solutions seem best clustered days 4-6 (Thu-Sat), but offer storm timing and energy transfer differences back over the Bering in particular for days 7/8. Accordingly opted to shift WPC forecast focus increasingly from the GFS/ECMWF to the GEFS/ECMWF ensemble means at these later time frames in a period with rapidly decreasing predictability. That said, there is a decent guidance signal to support additional deep Bering Sea storm genesis at these less certain longer time frames to monitor. Schichtel 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