Communities along the St. Lawrence River and Lake Ontario from Napanee to Mallorytown are under severe thunderstorm warnings Monday afternoon, as are the Maniwaki and Papineau-Lebelle regions of western Quebec. The Ottawa area is under a severe thunderstorm watch.
Environment Canada's warnings say a severe thunderstorm is in that area. Downpours of rain, wind gusts up to 90 km/h and hail are possible in this type of storm.
The watches for the Ottawa and Cornwall areas say conditions are favourable for the development of a similar storm this afternoon and early evening.
Ottawa's temperature is expected to fall from the 22 C reported at 1 p.m. to 15 C around sunset and 11 C overnight.
At 3:35 p.m., Environment Canada added severe thunderstorm warnings for the Maniwaki and Papineau-Labelle regions of western Quebec. According to the agency, meteorologists are monitoring a severe thunderstorm that can produce very strong gusts, heavy rain and hail from the size of a nickel to a ping pong ball.
Environment Canada issues severe thunderstorm warnings when meteorologists expect thunderstorms accompanied by large hail, damaging winds or torrential rain.