Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 330 PM EDT Wed Aug 28 2019 Valid 12Z Sun Sep 01 2019 - 12Z Thu Sep 05 2019 ...Deep low will lift to the eastern Bering Sea to threaten Alaska this weekend into early next week... The latest models and ensembles strongly agree that a potent low pressure system with surface pressures as deep as the 970 mb range in the models will lift from the Aleutians through the eastern Bering Sea Sunday through early next week as upper ridging over the eastern mainland slips eastward into Canada. A blend of the quite well clustered and reasonable 12 UTC GFS and ECMWF was used in this period of above average forecast confidence. This system will be a hazard for maritime interests and a downstream heavy weather/precipitation threat to focus into western/southwestern Alaska and acrossn the southern Alaska tier over time considering moisture transport and dynamic support aloft. Forecast spread increases by day 7/8, suggesting usage of just the more compatable ensemble means at these longer and less certain time frames. Upper trough amplification by then into the western Bering Sea/Aleutians may support a pattern favorable for another deepening low system. Schichtel 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 - Heavy rain across portions of mainland Alaska and the Aleutians, Sat-Mon, Aug 31-Sep 2. - High winds across portions of mainland Alaska and the Aleutians, Sat-Sun, Aug 31-Sep 1. 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