Thunderstorm Wind in Holmes County, Ohio

Tree downed in Millersburg.

At the surface, an occluded low drifted from northeastern WI to the central Upper Peninsula of MI during the early afternoon through early evening of the 17th. Simultaneously, the low's attendant warm front drifted eastward across central Lake Erie and far-western PA, and the low's attendant cold front swept eastward from near the northwest OH/northeast IN border and central IN to near the OH/PA border, which caused the warm sector to shrink with time. Scattered multicell thunderstorms and a few supercell thunderstorms developed along and ahead of the cold front, and persisted generally eastward across northern OH as the storms encountered weak to moderate MUCAPE and DCAPE, respectively, and moderate to strong effective bulk shear. This environment allowed storms to produce damaging hail and straight-line convective wind gusts, respectively. Three tornadoes also occurred amidst favorably-low mixed layer lifting condensation levels less than 1500 meters AGL and favorably-strong, surface-based effective storm-relative helicity.