We are watching the risk for severe thunderstorms across a wide portion of Eastern Ontario extending into Southern Quebec. The risk also extends into Southwestern Ontario and the Golden Horseshoe. The main threats include heavy rain and damaging winds. Moderate to large hail is possible.
Areas in yellow and marked with a '3' can expect a moderate risk for severe thunderstorms. In Ontario, this risk extends in the Niagara region including Niagara Falls and Fort Erie. In Eastern Ontario this risk extends from Oshawa through to Fenelon Falls, Haliburton and over to Stonecliffe including everything east of this line. This includes Pembroke, Ottawa, Bancroft, Perth, Kingsotn, Belleville and Brockville. There is some question as to whether this risk should extend further into the Niagara region to include St. Catharines and Welland, although, for this forecast, we have went against this. There is also question as to whether or not the storms will stay severe through to Cornwall before the sun goes down and the energy weakens, either way, we have included that region in this severe risk. Into Quebec, the risk extends from the Ontario border through to Dorval-Lodge and Lac McLennan, including Mont-Tremblant Park and Huntingdon. This includes Gatineau and Fort-Coulonge. The main threats in this region will include gusty winds near or over 90km/h. Moderate to large hail between 1.5 and 3cm is possible. Heavy rain over 40mm is possible. There is a non-zero tornado risk in the Bancroft-Perth-Kingston-Belleville-Peterborough region. Waterspouts are also possible over much of Lake Ontario and portions of Lake Erie.
Areas in green and marked with a '2' can expect a low risk for severe thunderstorms. In Ontario, this extends from Mattawa through Algonquin Park towards Dorset, Uxbridge, Toronto, Hamilton, Dunnville, Port Dover, Delhi and Brantford. There is some question as to whether risk risk should be extend towards Lake Huron and Georgian Bay as some weak development may occur later in the day which could pose a heavy rain threat. We have went against this in our forecast. Into Quebec, the risk extends towards Obedijiwan including La Tuque. This risk area also includes Shawinigan and Montreal. Most areas in this region should see non-severe thunderstorms although the risk is there. The main threats are damaging winds near 90km/h, heavy rain over 40mm and small to moderate sized hail (1-1.5cm, locally 2cm).
Areas in blue and marked with a 1' can expect mainly non-severe thunderstorms. This includes much of Southwestern Ontario and much of Northern Ontario. This also includes a large portion of Southern Quebec.
We will be closely watching today's storm for any possible rotation as well as waterspouts. If you see any waterspouts today, please send us your pictures (only if it's safe to do so).