Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 339 AM EDT Wed Aug 16 2017 Valid 12Z Wed Aug 16 2017 - 12Z Fri Aug 18 2017 ...There is a slight risk of severe thunderstorms over parts of the Middle Mississippi Valley/Central Plains... ...Heavy rain possible over parts of the Upper Great Lakes/Upper Mississippi Valley... ...Heavy rain possible over parts of the Central Plains... A storm over parts of the Central Plains will move northeastward to the Upper Great Lakes by Thursday evening. The system will produce showers and thunderstorms over parts of the Plains and parts of the Middle Mississippi Valley that will move eastward to the Great Lakes/Ohio Valley into the Lower Mississippi Valley by Thursday into Thursday evening. In addition, showers and thunderstorms will develop along and near the associated warm front over parts of the Tennessee Valley that will slowly expand eastward into the Mid-Atlantic overnight Wednesday. Meanwhile, moisture rich air over the Southeast and the Eastern Gulf Coast along with daytime heating will aid in producing showers and thunderstorms over the region on Wednesday and Thursday late afternoon into late evening. Additionally, weak upper-level energy over the Northern High Plains will aid in producing showers and thunderstorms over parts of the Northern/Central High Plains on Thursday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php