Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 AM EDT Sat Sep 15 2018 Valid 12Z Sat Sep 15 2018 - 12Z Mon Sep 17 2018 ...Florence to continue drifting slowly inland... ...Catastrophic flash flooding and prolonged river flooding likely over portions of the Carolinas and the Southern/Central Appalachians... ...There is a slight risk of severe thunderstorms over parts of the Carolinas Coast... ...Heavy rain possible over parts of Southwestern Texas... Tropical Storm Florence is forecast to move westward to Western South Carolina before turning northwestward then north while slowly weakening by Monday. Heavy rain will develop over parts of the Carolinas through Sunday afternoon. Rain will expand into parts of the Southern/Central Appalachians by Sunday evening. This surge is also likely along portions of the South Carolina coast. Please check the National Hurricane Center advisory for the latest track and intensity forecast. Meanwhile, tropical moisture and daytime heating will aid in producing showers and thunderstorms over Florida through Sunday evening. In addition, southeasterly flow off the Gulf of Mexico and upper-level energy will aid in producing showers and thunderstorms over parts of Western/Central Gulf Coast into parts of the Southern Plains through Sunday evening into Monday. Furthermore, a front extending from parts of the Upper Great Lakes/Upper Mississippi Valley southwestward to the Great Basin will be quasi-stationary through Sunday evening. Showers and thunderstorms will develop along and near the boundary over the Upper Mississippi Valley/Upper Great Lakes into parts of the Northern Plains that will lift northward into Southern Canada by Sunday. Elsewhere, upper-level energy moving onshore over Central California will move northeastward into the Northern High Plains by Sunday morning. The energy will aid in producing rain with embedded thunderstorms over parts of the Northern Intermountain Region/Northern Rockies overnight Saturday moving into Canada by Sunday evening. Also, weak onshore flow over the Pacific Northwest will aid in producing rain over the area through Sunday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php