Extended Forecast Discussion NWS Weather Prediction Center College Park MD 159 AM EDT Thu Oct 29 2020 Valid 12Z Sun Nov 01 2020 - 12Z Thu Nov 05 2020 ...Overview... An upper trough is forecast to move through the northeastern 1/4 of the CONUS Sun-Mon with a reinforcing shot of cool/cold air. The pattern will transition toward zonal flow by the middle of the week with little in the way of precipitation outside the Pac NW as a couple systems push inland. Milder than normal temperatures are expected for much of the western half of the lower 48. ...Guidance Evaluation/Preferences... Through the 12Z/18Z model cycle, deterministic runs of the GFS/ECMWF/Canadian/UKMET offered a reasonably-clustered starting point for Sun-Tue though the GFS runs were a bit quicker than the rest into the West on Tue. This was not unreasonably given the transition toward more zonal flow but the ECMWF-led consensus was already a bit quicker than the previous forecast. Increased ensemble weighting for next Wed-Thu as the deterministic cluster was slower than the ensemble consensus over Canada but that may not affect much of the CONUS. Over California/Southwest, upper low is forecast to move through the Four Corners around late Tue into early Wed and into TX Thu but likely with little fanfare. ...Weather/Hazard Highlights... The respectable cold front in the Midwest early Sun will sweep through the East Coast later in the day, ushering in the coldest air of the season to some areas of the Mid-Atlantic. Morning lows on Monday may flirt with freezing toward the I-95 corridor with highs only in the 40s through Virginia. Temperatures will moderate Tuesday onward as heights rise and NW winds turn to W and SW by mid week. In the West, temperatures will be about 5-15 degrees above normal to start the period, spreading eastward into the Plains by Tuesday and Great Lakes/Northeast Wednesday/Thursday. Precipitation will generally be light and mostly around the Great Lakes Sun/Mon. With westerly flow aloft into the West, coastal Oregon and especially Washington will see an increase in valley rain and mountain snow Tue-Thu. Fracasso 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