Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 352 AM EDT Tue Aug 20 2019 Valid 12Z Tue Aug 20 2019 - 12Z Thu Aug 22 2019 ...Thunderstorms that could cause severe weather and flash flooding are possible in the central U.S. ahead of a cold front... ...Excessive heat is expected for the Desert Southwest and across the midsection of the country as warmth persists across the bulk of the U.S.... As cold fronts make their way into the north-central U.S. today and move south and eastward on Wednesday, this will provide a focus for thunderstorms. On Tuesday and Tuesday night, a Slight to Enhanced Risk of severe weather is in place from the Storm Prediction Center for the Central Plains eastward into the Middle Mississippi and Ohio Valleys, with potential for severe storms in the vicinity of a surface low in the Upper Midwest as well. Some heavy rainfall and localized flash flooding are also possible with the storms Tuesday. On Wednesday, the thunderstorm threat shifts a bit southward as the front slowly moves, and flash flooding remains forecast for the Central Plains to Middle Mississippi Valley with a few severe storms possible as well. A portion of the cold front will move farther east toward the Lower Great Lakes by Wednesday evening, and severe thunderstorms are expected for portions of the Northeast ahead of it. South of the cold front, warmer than average temperatures remain likely for much of the U.S. Excessive Heat Warnings are in place for much of the Southwest, where record highs into the 110s could be set both Tuesday and Wednesday. Heat Advisories and some Excessive Heat Warnings are also widespread across parts of the Plains, Mississippi Valley, and Tennessee Valley. Behind the cold front, high temperatures in the 70s are expected for the Northern Plains to Upper Mississippi Valley by Wednesday. In the Pacific Northwest, a cold front is expected to come through on Wednesday, bringing rain and cooler temperatures. Some monsoonal moisture should return to the Southern Rockies/High Plains over the next couple of days, so isolated showers and thunderstorms are possible there. Lingering showers and thunderstorms will continue along the central Gulf Coast, with potentially heavy downpours. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php