A powerful frontal system will drive rounds of rain and thunderstorms across the central U.S. through Thursday, with the heaviest precipitation expected from the central Plains to the Great Lakes. ECMWF model output shows multiple waves of rainfall—some exceeding 1.5 inches—spreading northeastward from the southern Plains Tuesday night into the Midwest by Wednesday. As the system shifts east, showers and storms will expand into the Ohio Valley, Appalachians, and Mid-Atlantic.