Extended Forecast Discussion NWS Weather Prediction Center College Park MD 207 AM EDT Tue Jul 07 2020 Valid 12Z Fri Jul 10 2020 - 12Z Tue Jul 14 2020 ...Guidance/Predictability Assessment... The WPC product suite was mainly derived from a composite of reasonably clustered guidance from the 18 UTC GFS/GEFS mean, 12 UTC ECMWF/ECMWF ensemble mean and 01 UTC National Blend of Models. This blend maintains good WPC continuity and seems supported by newer 00 UTC model guidance. Smaller scale differences remain with an Eastern Seaboard coastal low currently being monitored by NHC. The WPC composite offers moderate development versus deeper recent UKMET runs, whose solutions fall within ensemble forecast spread and seem to benefit from a more offshore track east of the main upper trough and over warmed water. . ...Weather Pattern/Hazard Highlights... Upper trough energies will periodically work inland over an unsettled Northwestern U.S. and western Canada. A steady stream of ejecting impulses then progress downstream over southern Canada and the U.S. northern tier. This will force moderating fronts over the broad region and spawn some strong to severe thunderstorms. Convective rainfall potential may focus from the Midwest to the Northeast and with a stalled/wavy front over the humid South/Southeast. Triple digits maximum temperatures (approaching/exceeding some heat records) are likely from portions of CA and the Southwest/southern Great Basin to the south-central Plains, with heat indices making it feel closer to 115 in some places. A heavy rain/weather threat is also expected to lift from the coastal Mid-Atlantic to New England contingent on potential coastal low development and track. 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