LONDON, Ont. - Tornado warnings issued for central Ontario ended Saturday night but severe thunderstorm watches and warnings remained in effect for parts of the province's central and southern regions.

A string of tornado warnings were issued as storms passed through southern Ontario on Saturday afternoon, including the London, Toronto and Durham regions.

Environment Canada warned that its meteorologists were tracking severe thunderstorms capable of producing very strong wind gusts, up to nickel-size hail and heavy rain.

Warnings are an urgent message that severe weather is either occurring or will occur, whereas watches indicate that there's potential for the severe weather to occur.

Tornado warnings are issued when imminent or occurring thunderstorms are likely to produce or are producing tornadoes.