Extended Forecast Discussion NWS Weather Prediction Center College Park MD 153 AM EST Thu Dec 03 2020 Valid 12Z Sun Dec 06 2020 - 12Z Thu Dec 10 2020 ...Guidance Evaluation/Preferences... Through the 12Z/18Z guidance, ongoing saga of model disappointment continued, owing to a rather unpredictable shortwave pattern amid a mostly predictable longwave pattern. Continued to rely on a broad consensus as there appears to be no clear trend in evolution as the details change daily. Overall, ridging in the Northwest favors troughing to its south and over the eastern half of the CONUS, modulated by several features with overall lower predictability than normal. By next Wed/Thu, preferred some aspects of the ECMWF/Canadian over the GFS with the Pacific flow but continued to heavily rely on the ensemble means as a stabilizer. Fate of the lost upper low off SoCal/Baja is in question but Pacific pattern suggests it will get tugged/pushed back inland in some form. ...Sensible Weather and Hazards... Potentially impactful system exiting the Northeast will pull away Sunday, leaving the CONUS in a relatively dry pattern for the period. Ridging will promote milder than normal temperatures for the High Plains to Upper Midwest/Corn Belt into the central Plains, perhaps by 15-25 degrees. Actual reading will approach 60 degrees into South Dakota on Tuesday. Colder than normal temperatures are favored for much of the East to start the period (Sun-Tue) before trending back toward more typical values. Rainfall will be mostly confined to Florida astride the cold/stationary front and in advance of a secondary front, as well as in the Pac NW as a front moves ashore. Amounts will be light to perhaps modest in higher elevations where snow is likely. Fracasso 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 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