Tornado warning downgraded to watch in Lanark County | CBC News

Environment Canada says severe thunderstorms are developing over the Ottawa-Gatineau region late Thursday morning and afternoon and some of those storms may produce tornadoes.

Tornado watches cover an area from Renfrew to the Quebec border and from Maniwaki through Ottawa-Gatineau to Kingston until late afternoon.

North of Gatineau, it's expected to last until the evening.

A tornado watch was briefly updated to a tornado warning for eastern Lanark County. That ended around 11:30 a.m.

Ottawa, the Smiths Falls, Kemptville and Westport areas have a severe thunderstorm warning about a storm with very strong winds.

Parts of Western Quebec without a tornado watch have a severe thunderstorm watch about storms that could bring hail, heavy rain and strong winds this afternoon and evening.

Areas west of the watch such as Pembroke and Bancroft have a special weather statement about heavy rains that could drop at least 30 millimetres by this evening.

Tornado watches mean forecasters see weather conditions that could produce a tornado.

Tornado warnings mean a tornado has been reported or there's solid evidence a tornado is imminent.

Under a warning, advice includes going indoors to a strong building on its lowest floor possible away from outside walls.

It's a similar dynamic for severe thunderstorms: watches are when they may develop, warnings are for when there's evidence one is happening.