Extended Forecast Discussion NWS Weather Prediction Center College Park MD 237 AM EDT Mon Jul 06 2020 Valid 12Z Thu Jul 09 2020 - 12Z Mon Jul 13 2020 ...Guidance/Predictability Assessment... The WPC medium range product suite was made from a composite blend of reasonably clustered larger scale guidance from the 18 UTC GFS/GEFS, the 12 UTC ECMWF/ECMWF ensemble mean, the 01 UTC National Blend of Models and WPC continuity. Widespread differences at the smaller scales is particularly evident with the development of an Eastern Seaboard coastal low with origin from convection over the northeastern Gulf of Mexico now being monitored by NHC. The WPC blend tends to mitigate the less predictable smaller scale system differences and maintains good product continuity. It should be noted that the 12/00 UTC UKMET develops the coastal low much more earnestly offshore and that remains plausible. However, the latest 00 UTC GFS/ECMWF/Canadian have not trended toward the outlier UKMET. ...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 Northern Plains southeastward across the Midwest. Well into the triple digits maximum temperatures will occur from the Desert Southwest/southern Great Basin to the south-central Plains, with hot and humid weather over much of the central and eastern U.S. to include some record heat. A heavy rain/weather threat is also expected to lift from the Southeast to coastal Mid-Atlantic and New England contingent on upper support/coastal low development. 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