Extended Forecast Discussion NWS Weather Prediction Center College Park MD 118 PM EDT Sun Jul 05 2020 Valid 12Z Wed Jul 08 2020 - 12Z Sun Jul 12 2020 ...Guidance/Predictability Assessment... The WPC medium range product suite was primarily derived from a composite blend of the 06 UTC GFS, the 00 UTC ECMWF/Canadian, and the 00 UTC ECENS/06 UTC GEFS ensemble means. There is a reasonably compatible larger scale pattern evolution aloft, but with some significant differences at the smaller scales, particularly across the eastern U.S. The described blend seems to smooth out much of the less predictable smaller scale system differences. This forecast update maintains relatively good WPC product continuity. ...Weather Pattern/Hazard Highlights... Pacific upper trough energies will work inland over an unsettled Northwest and western Canada. A steady stream of ejecting impulses then progress downstream over southern Canada and the U.S. northern tier. This will force a series of moderating fronts across the region and spawn periods with strong instability/convection and locally heavy downpours. Potential may focus from the Northern Plains to the Upper Midwest. Lead flow and mean upper ridging may bring the most anomalous heat over the Midwest/Northeast. Elsewhere, triple digit maximum daytime temperatures will occur from the Desert Southwest/southern Great Basin to the south-central Plains and hot and humid weather (including some record warm overnight temperatures) will rule a broad expanse south of these fronts over much of the central and eastern U.S. Some heavy convective downpours/local runoff issues may focus over the South/Southeast around a slow moving upper trough/closed low. Potential development of a leading and slowly lifting coastal low and frontal system midweek into next weekend may also focus heavy rainfall/weather for coastal portions from the Southeast/Mid-Atlantic to New England. Ryan/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