Extended Forecast Discussion NWS Weather Prediction Center College Park MD 222 PM EDT Fri Aug 07 2020 Valid 12Z Mon Aug 10 2020 - 12Z Fri Aug 14 2020 ...Overview and Guidance/Predictability Assessment... Guidance reasonably agrees that two closed upper lows will track eastward over Canada as trough energies and moderating/convection focusing fronts work their way across the northern half of the U.S.. Underneath, hot upper ridging will prevail over the southern half of our nation. The WPC medium range product suite was mainly derived from a composite of well clustered guidance from the 06Z GFS and the 00Z ECMWF in a pattern with above normal predictability. Forecast spread growth and flow continuity favors a transition into day 7/Fri toward a blend of the 00Z EC ensemble mean and the 06Z GEFS. ...Weather/Hazard Highlights... A cold front working it way across the northern Plains will likely trigger clusters of thunderstorms which could bring areas of heavy rainfall from the upper Midwest into the Great Lakes later on Monday into Tuesday. As the trailing portion of the cold front stalls across the central Plains, episodes of strong to severe thunderstorms are likely to track from the north-central U.S. toward the eastern U.S., from Tuesday through the end of next week. Meanwhile, the Southeast/Florida will see diurnal convection of varying intensity, with a weakening front over the Southeast providing an added focus early in the period. Within the broad area of shower/thunderstorm potential there will likely be areas of heavy rainfall. Temperatures are not expected to stray too far from normal during the medium-range period for the entire lower 48. Nevertheless, above normal temperatures will prevail across the northern tier states into New England even behind the cold front due to less cloudiness. Meanwhile, a good chance of afternoon/evening thunderstorms will keep high temperatures cooler than normal for the central to southern portions of the country. Over the southern High Plains, triple-digit high temperatures are forecast to continue through the end of next week. In contrast, cooler air will work its way across the Northwest behind a Pacific cold front. Kong/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