Flash Flood in Crawford County, Ohio

Reports and photos of six inches or more of flowing water over Stetzer Road east of Bucyrus. Water across the roadways also reported along portions of OH-96 in eastern Crawford County. Radar estimated 2 to 2.5 inches of rainfall in a 75-90 minute period.

Knox County resided in the warm and moist sector during the early through late evening of the 5th as a cold front swept eastward from northwestern IN and the Lower Ohio Valley to far-western OH and far-southeastern IN. Ahead of the cold front, scattered thunderstorms, including supercells, developed along a surface trough axis and resided in an environment favorable for tornadic supercells. This environment was comprised of moderate MUCAPE and effective bulk shear, respectively, and favorably-low mixed layer lifting condensation levels near 750 meters AGL. An approaching mesoscale convective vortex from southwest OH backed surface winds over and near Knox County, which lead to to significant veering and strengthening of low-level winds with height and surface-based effective storm-relative helicity of about 150 meters squared per second squared. One supercell in particular tracked generally eastward and then northeastward across southern and eastern portions of Knox County. This storm produced one tornado and one instance of straight-line wind damage. Heavy rainfall rates from the storms throughout the evening produced localized flash flooding in portions of Know, Morrow, and Crawford Counties.