Extended Forecast Discussion NWS Weather Prediction Center College Park MD 250 AM EDT Fri Oct 30 2020 Valid 12Z Mon Nov 02 2020 - 12Z Fri Nov 06 2020 ...Heavy Precipitation pattern for the Pacific Northwest next week... ...Overview... An anomalously strong and cold upper trough will move through the Northeast early next week. Primarily fast zonal flow then sets up over the nation. Aside from wet weather systems increasingly impacting the Northwest with upper trough amplification over time, much of the lower 48 will see little precipitation next week. Below normal temperatures over the East will moderate, while the West will stay above normal for much of next week. ...Guidance Evaluation/Preferences... Model and ensemble forecasts are in much above normal agreement through medium range time scales, strongly bolstering forecast confidence. A blend of the latest GFS/ECMWF and GEFS/ECMWF in particular offers a quite well clustered forecast consistent with the National Blend of Models and WPC continuity. Blend weights were shaded from the models to the ensembles over time to address lingering differences. ...Weather/Hazard Highlights... Respectable cold fronts sweeping over the East into early next week will usher in cold air with some record lows in the Mid-Atlantic as well as strong/high winds for a snowy Northeast. Lake effect snow enhancement will be possible downwind of Lake Erie and Ontario. Above normal temperatures over the West will also spread eastward next week into the Plains/Midwest/Great Lakes/Northeast. Heaviest precipitation totals will focus over the Pacific NW, particularly Washington State with a series of atmospheric rivers. Rains and elevation snows will spread over much of the Northwest later next week. Schichtel Additional 3-7 Day Hazards information can be found on the WPC medium range hazards chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation, winter weather outlook probabilities and heat indices are at: https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml