A line of heavy thunderstorms was advancing into the Akron-Canton area at about 7 p.m. Monday, according to the National Weather Service in Cleveland.

Severe thunderstorm warnings were posted for northern Summit County and from Marietta north to near Canton. The most severe storm was passing into Cuyahoga county.

The weather service cautioned that the storms could produce large hail and an isolated tornado.

A tornado watch was in effect for the western half of Ohio. The watch extends eastward across the state to Medina, Wayne and Cuyahoga counties’ western borders.