Special weather statements issued for hard-hit areas of southern Ontario

Wednesday, July 10, 2013, 7:31 AM -

Less than 24 hours after record-breaking rain inundated southern Ontario, causing localized flooding and a traffic nightmare in the GTA, Environment Canada has issued a new batch of special weather statements.

The statement - which covers a large swath of southern Ontario - including hard-hit areas like Toronto and Mississagua - warns of the potential of torrential rain, damaging wind and hail.

As clean-up continues and residents attempt to dry out, any additional rainfall is the last thing people need. 

"There's potential for additional rainfall Tuesday night across southern Ontario, including the GTA, and risk for severe thunderstorms on Wednesday across southern Ontario and southern Quebec," says Dayna Vettese, a meteorologist at The Weather Network.

Toronto flood photo courtesy of Sean Raymer

Will Tuesday be as bad as Monday? 

While amounts may be heavy locally, computer models are suggesting heavy rain across southern Ontario.

"Amounts will be variable, as they typically are with summer storms," Vettese says, "but the highest amounts will generally not exceed 20-30 mm and we don't expect a repeat of Monday's deluge in Toronto."

Tuesday's rain is not expected to cause any additional flooding, but infrastructure compromised by Monday's storm could be weakened further.

Rain is expected to continue through the evening and into the Wednesday morning commute.

RT @bradrousseau: Quick graphic with brief outline to show greatest storm potential is today for across ON. #onstorm https://t.co/Syu6c3Sv5x

— Dayna Vettese (@daynavettese) July 9, 2013

Forecasting severe thunderstorms

According to Vettese, it's much easier to forecast where storms will hit, but forecasting how they will behave once they form can be very difficult. 

"It's extremely hard to tell how the storms will interact with each other and any local atmospheric phenomena. On Monday, all of the ingredients were there for the thunderstorms to develop, but once we started to see the flooding in Angus, we knew it'd be more of a flooding event," says Vettese. 

The exact impact the storms were going to have on Toronto were initially unknown, and the warning from Environment Canada was actually not issued until the storm had begun.

"Around 3 o'clock in the afternoon, nothing was going on in Toronto, it was a hot, humid day and storms just busted in from the northwest," says Chris Scott, chief meteorologist at The Weather Network. "And they kept developing because the winds were feeding in from the south and the east, so that's why we had so much rain." 

Thunderstorm risk

MORE RAIN POSSIBLE: Tune into The Weather Network on TV as we continue to bring updates on the flood situation and track the latest storms.