National Weather Service United States Department of Commerce
November 17, 2013
Severe Weather

Strong surface low pressure moved northeast from the Mississippi Valley into the Great Lakes during the evening of November 17, 2013. A cold front trailing the low moved quickly east through the Ohio Valley. Ahead of the front, strong southerly winds brought very warm and moist air into the region. Very strong winds in the middle and upper atmosphere spread over this unstable enviroment, leading to a severe weather outbreak. Farther west in Indiana and Illinois, more instability was present, and supercell thunderstorms developed and produced strong to violent tornadoes. Instability weakend over Ohio due to persistent cloud cover and precipitation earlier in the day, and when the storms moved into our area, they congealed into a broken squall line driven by the cold front. Severe winds of over 60 MPH occurred with the strong showers and thunderstorms (although lightning diminished with time) along the front. A few discrete cells still managed to form ahead of the squall line, which led to a concern of tornadoes with abundant low level wind shear, in addition to the possibility that a weak, brief tornado could develop along the squall line.
In addition to the severe weather, heavy rains during the overnight hours and early morning of November 17 led to some minor flooding in northern Kentucky. The vigorous low pressure system also caused gusty ambient winds throughout the day.