Thunderstorms that formed southeast of Dayton on Friday evening produced outflows that collided and helped enhance rainfall around Xenia.
Outflow boundaries, or gust fronts, are produced when cooler, rain-cooled air sinks, hits the ground and ushers out ahead of storms. The cooler air can act like a mini cold front, forcing air ahead of the boundary upward. This upward motion causes more clouds to form and can even generate or enhance thunderstorms.
This radar loop video from 5 p.m. to just after 7 p.m. Friday shows two outflow boundaries, produced by thunderstorms, colliding. This collision causes an enhanced upward motion and increased rainfall rates over Greene County. Radar estimates nearly 2 inches of rainfall fell within an hour between 6:30 and 7:30 p.m. near Xenia.
