Severe weather threatens southern Ontario

Thursday, July 3, 2014, 12:43 PM - "Conditions are favourable for the development of severe thunderstorms which may produce tornadoes."

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That was the messaging included in a tornado WATCH that was issued for parts of southern Ontario Thursday morning. 

At 10:22 am ET, a tornado warning was issued for St. Thomas, Aylmer and eastern Elgin County.

That warning was dropped about 20 minutes later, and the watch was also lifted before 11 am. 

A crazy 45 minutes to say the least. 

"We had the storms moving in over Lake Erie and it moved into an environment of high shear," says Weather Network meteorologist Dayna Vettese. "That means there's a lot of rotation in the atmosphere."

Some strong rotation was detected as the storm came ashore, but as it moved over land in the Port Burwell area, it lost its rotation, Vettese adds.

The severe thunderstorm risk however, remains in place. 

"We have to be aware that areas from about Tillonsburg over to Hamilton and into the Niagara region, be on alert for thunderstorms," Vettese says.

Take cover immediately, if threatening weather approaches, officials warn.

"In the event of a tornado, or if a tornado warning is issued for your area, it is recommended you take the following actions: Go indoors to a room on the lowest floor, away from outside walls and windows, such as a basement, bathroom, stairwell or interior closet. Leave mobile homes, vehicles, tents, trailers and other temporary or free-standing shelter, and move to a strong building if you can. As a last resort, lie in a low spot and protect your head from flying debris," says Environment Canada.