Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 425 PM EST Thu Feb 11 2021 Valid 12Z Mon Feb 15 2021 - 12Z Fri Feb 19 2021 ...Guidance/Uncertainty and Weather/Hazards Assessments... An active, stormy pattern is expected across southern portions of the region as a series of low pressure systems track from the Bering Sea across the Gulf and southern Mainland within the broad upper level trough. Meanwhile, the North Slope and areas into the Interior will mainly be cold and dry as impulses traverse through the upper ridge. Below normal temperatures across the Panhandle initially with moderate by early next week. These deep lows tracking from the Bering to the western Gulf of Alaska may be impactful to the Aleutians, southwest Alaska and nearby Alaska Peninsula and Kodiak as the flow wraps around. Due to model spread increasing by mid/late periods over the eastern Gulf of Alaska, there is uncertainty as to whether organized precipitation will affect southern Mainland and the Southeast. Overall the deterministic models and their respective ensemble means are fairly clustered and in mutual agreement with multiple systems passing through the Bering Sea. A combination of the 12Z GFS/ECMWF/CMC and GEFS/ECMWF ensemble means provided a decent forecast for the extended periods. The weighting of the ensemble means were increased for days 7 and 8 where the spread over the eastern Gulf was more pronounced. Campbell Hazards: - Much below normal temperatures across portions of the Alaska Panhandle, Sun, Feb 14. 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 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