Extended Forecast Discussion NWS Weather Prediction Center College Park MD 206 AM EST Sun Nov 01 2020 Valid 12Z Wed Nov 04 2020 - 12Z Sun Nov 08 2020 ...Heavy precipitation for the Pacific Northwest... ...Overview and Weather/Hazard Highlights... Generally zonal large-scale flow can be expected across the CONUS for much of the coming week, with the exception of some embedded shortwaves. Troughing comes into the West by the end of the week, spreading cooler temperatures and precipitation to a larger proportion of the West after some potentially heavy precipitation in the Pacific Northwest given moist inflow and a series of frontal passages, especially in the Cascades and Olympics. Given the deep troughing set to engulf the West and slow eastward translation during the week, rain and lowering elevation snows are forecast to spread across the North-central Great Basin/Rockies/High Plains and farther south into CA. Other than that, most of the CONUS should stay dry through the medium range period, with the exception of rain over the Florida peninsula under easterly post-frontal flow to the north of a tropical development in the Caribbean. ...Guidance Evaluation/Preferences... A composite blend of well clustered guidance from the latest GFS/ECMWF and GEFS/ECMWF ensemble means seems to provide a good starting point for the day 3/4 Wed/Thu forecast package across the CONUS. Leaned heavy on the ECMWF ensemble mean Fri-next weekend. The ECMWF ensemble mean seems to best capture flow amplification over the CONUS, but also offers the closest depiction of the NHC Caribbean tropical system track. The GFS/GEFS are deeper and closer to FL. 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