Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Sat Jun 30 2018 Valid 00Z Sun Jul 01 2018 - 00Z Tue Jul 03 2018 ...Severe weather and flash flooding possible for parts of the Plains to the Upper Great Lakes... ...Widespread and dangerous heat wave to continue through the weekend for much of the eastern half of the country... The ongoing heat wave is expected to continue over much of the eastern half of the country, where afternoon highs could be as much as 10 to 20 degrees above normal. These values combined with high humidity, will lead to dangerous heat indices approaching or exceeding 100 degrees for many places. Daytime maximum and overnight high-minimum temperature records are in jeopardy and widespread excessive heat warnings/watches and heat advisories are in effect from the Central Plains to the Ohio Valley and parts of the Northeast. Additionally, hot and dry conditions across portions of California and the Southwest will keep an elevated risk of fire danger in place. Numerous locations have red flag warnings in effect. A cold front moving slowly eastward and a surface low lifting through the upper Midwest/Great Lakes is providing a focus for strong to severe convection and heavy to excessive rainfall. The Storm Prediction Center has highlighted portions of the eastern Central Plains to the Upper Midwest/Great Lakes and the Northeast within a slight to enhanced risk for severe weather. The primary threats with these storms will be wind and large hail, but a few tornadoes cannot be ruled out. These storms are also expected to be very efficient rain producers, which potentially could lead to flash flooding.By Sunday, this system becomes a bit more progressive as the surface low races northward through the upper Great Lakes, which should limit the overall flash flood threat, but severe weather will remain a possibility along the cold front. Refer to the products issued by the Storm Prediction Center and WPC for additional details. Across the Southeastern U.S., a weak surface wave will keep showers and thunderstorms in the forecast, with heavy rainfall possible. Campbell/Santorelli Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php