Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 356 AM EDT Wed Aug 15 2018 Valid 12Z Wed Aug 15 2018 - 12Z Fri Aug 17 2018 ...There is a slight risk of severe thunderstorms over parts of the Central/Northern Plains. ...Heavy rain possible for parts of the Western Ohio Valley into parts of the Lower Mississippi Valley... ...Heavy rain possible for parts of the Northern Plains... A front extending from the Northeast across the Great Lakes then southwestward to parts of the Southern Plains has a wave of low pressure over Middle Mississippi Valley that will move northeastward to the Great Lakes by Thursday evening. The system will produce showers and thunderstorms over parts of the Middle/Lower Mississippi Valley and parts of the Southern Plains that will move northeastward to the Great Lakes/Ohio Valley and parts of Northern Mid-Atlantic as well as parts of the Lower/Middle Mississippi Valley by Thursday evening. Along the front, showers and thunderstorms will develop along and near the boundary from parts of the Northeast to the Upper Great Lakes that will move off the Northeast Coast by Thursday morning. In addition, upper-level energy over parts of the Northern High Plains will move southeastward to parts of the Middle Mississippi Valley by Thursday evening. The energy will produce showers and thunderstorms over parts of the Northern Plains that will move eastward into the Northern/Central Plains and parts of the Upper Mississippi Valley by Thursday evening. Meanwhile, upper-level energy over parts of the Lower Mississippi Valley will move eastward into the Tennessee Valley/Central Gulf Coast by Thursday. The energy will aid in developing showers and thunderstorms over parts of the Central Gulf Coast from Wednesday morning into Thursday evening. Additionally, tropical moisture over parts of the Southeast will aid in producing showers and thunderstorms through Thursday. Elsewhere, monsoonal moisture and daytime heating will aid in producing showers and thunderstorms over parts of the Southwest/Great Basin and the Central/Southern Rockies through Thursday evening. The showers and thunderstorms will have the greatest areal coverage during the late afternoon into the late evening on Wednesday and Thursday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php