Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 323 AM EDT Sat Jul 20 2019 Valid 12Z Sat Jul 20 2019 - 12Z Mon Jul 22 2019 ...Dangerous heat wave ongoing from the Central U.S. to the East Coast... ...There is a slight risk of severe thunderstorms over parts of the Great Lakes into the Middle Mississippi Valley and the Central High Plains... There is a slight risk of excessive rainfall from parts of the Central High Plains into parts of the Middle Mississippi Valley... Excessive Heat Warnings and Heat Advisory extend from parts of the Texas Panhandle to the Middle Mississippi/Ohio Valleys and parts of the Great Lakes as well as parts of the Northeast southward to the Southern Mid-Atlantic as upper-level ridging extends from parts of the Southwest eastward to the Northeast/Mid-Atlantic. Daytime temperatures in the mid to upper 90s combined with high humidity will result in heat indices as high as 115 for some. As overnight temperatures will provide little relief as temperatures struggle to get below the upper 70s or even low 80s. Possible record high minimum temperatures are forecast from parts of the Middle Mississippi Valley into the Great Lakes/Ohio Valley and from parts of New England southward to the Carolinas into the Tennessee Valley on Saturday into Monday. Furthermore, record high temperatures are forecasted for parts of the Great Lakes/Ohio Valley into parts of the Mid-Atlantic on Saturday into Sunday. Please see www.weather.gov for the latest on the coverage of warnings and advisories, and also tips on how to stay safe in this heat. A slow moving front crossing the Great Lakes into Central Plains will focus convection over this region, with SPC highlighting the Great Lakes into parts of the Middle Mississippi Valley with a slight risk for severe thunderstorms. The system also has a slight risk of excessive rainfall that could produce flash flooding on Saturday. The showers and thunderstorms will extend from parts of the Mid-Atlantic to the Middle Mississippi Valley by Monday morning. Elsewhere, diurnally driven showers and thunderstorms are expected over much of the Southeast into the Central Gulf Coast and Tennessee Valley Saturday into Monday. Overnight Sunday, showers and thunderstorms will develop over parts of the Central/Southern High Plains into Monday morning. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php