St. Catharines, Grimsby and Northern Niagara now under a severe thunderstorm warning
Environment Canada says conditions are favourable for the development of severe thunderstorms that may be capable of producing strong wind gusts and large hail.
Winds may reach 90 to 110 km/h, and hail be as large as a ping pong ball.
As we continue with the heat wave, thunderstorms are expected to develop early this afternoon.
It will clear late today.
Meantime, a heat warning continues for Niagara today with temperatures expected to feel like 40 degrees.
The high today is 29, but it's expected to feel more like 39. The UV index today is 'extreme.'
The heat wave lifts Friday with a high of 26, but feeling more like 29.
A cool weekend is in the forecast with a high both Saturday and Sunday of 19.
Extreme heat affects everyone, but the risks are greater for young children, pregnant women, older adults, people with chronic illnesses and people working or exercising outdoors.
Never leave people or pets inside a parked vehicle.