Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Mon May 21 2018 Valid 12Z Mon May 21 2018 - 12Z Wed May 23 2018 ...there is a slight risk of severe thunderstorms over parts of the Ohio Valley... ...Heavy rain possible over parts of the Southwest/Eastern Gulf Coast... A front extending from the Mid-Atlantic westward to low pressure over the Ohio Valley/Middle Mississippi Valley then southward across parts of the Lower Mississippi Valley into the Southern Plains will have the southern half of the boundary dissipate by Monday evening. Overnight Monday, a new boundary develops over parts of the Central Plains into the Ohio Valley/Middle Mississippi Valley. The surface low will slowly move northeastward to the Northern Appalachians by Tuesday evening pulling the associated front to portions of the Mid-Atlantic across the Southern Ohio Valley. Showers and thunderstorms will develop along and near the boundary from parts of the Mid-Atlantic to the Middle Mississippi Valley and southward across parts of the Lower Mississippi Valley into the Southern Plains will slowly lift northeastward to the Northeast on Tuesday into Tuesday evening while showers and thunderstorms continue over parts of the Ohio Valley into the Lower Mississippi Valley. In addition, upper-level energy over the Southeast will become quasi-stationary over parts of the Eastern Gulf Coast through Tuesday evening as additional upper-level energy moves northward along the Southeast Coast. The energy will aid in producing showers and thunderstorms over parts of Florida into parts of the Eastern Gulf Coast that will expand westward into the Tennessee Valley and northward into the Southern Mid-Atlantic through Tuesday evening into Wednesday. Meanwhile, a deep upper-level trough over the West Coast will slowly move into parts of the Great Basin while weakening by Tuesday evening. Upper-level dynamics and moisture moving northwestward out of the Western Gulf of Mexico will aid in developing showers and thunderstorms over parts of the Southern High Plains into the Southern Rockies through Tuesday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php