Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 355 AM EDT Wed Aug 21 2019 Valid 12Z Wed Aug 21 2019 - 12Z Fri Aug 23 2019 ...A front will focus thunderstorms in the Central Plains, Middle Mississippi Valley, and Ohio Valley through Thursday... ...Severe weather and flash flooding are possible in the Northeast today... ...Another day of dangerous, potentially record-breaking heat across the Southwest while heat and humidity persist across much of the country... A frontal system is forecast to move slowly southward through the Central Plains and Middle Mississippi Valley regions over the next couple of days, and press eastward a little more progressively across the Ohio Valley, Great Lakes region, and eventually through the Northeast. This front will provide a focus for potentially multiple rounds of rain and thunderstorms in the Central Plains to Middle Mississippi Valley today, southward into Oklahoma on Thursday. Flash flooding is a threat with these storms, with high rainfall rates and the potential for storms to repeat over the same areas. Slight Risks of excessive rainfall/flash flooding are in place for these areas, and some isolated severe weather cannot be ruled out. Scattered showers and thunderstorms are possible farther south of the front into the Lower Mississippi and Tennessee Valleys and Southeast as well. Ahead of the main cold front, thunderstorms are likely in the Northeast today as upper-level energy moves through. Severe weather and flash flooding are both possible with these storms, and Slight Risks for both threats are in place for today. Dangerous heat is forecast once again in the Southwest, where high temperatures in the mid-110s could set records. Temperatures in the 90s are expected northward in the Intermountain West today. Farther east, Heat Advisories are in place for portions of the Southern Plains to Lower Mississippi and Tennessee Valleys, where heat and humidity could combine to create high heat indices. The Eastern Seaboard will also remain warm. Meanwhile, behind the cold front into the Northern/Central Plains and Upper Midwest, below average temperatures are expected today. On Thursday, the Ohio Valley and Lower Great Lakes region will cool down by several degrees as the cold front passes. A cold front is forecast to pass through the Pacific Northwest today, bringing cooler temperatures and rain. Below average temperatures will move into the Northern Great Basin and Northern Rockies on Thursday. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php