We are currently watching the risk for widespread showers and thunderstorms across portions of Quebec as well as Eastern Ontario. Some of these isolated to scattered thunderstorms may be severe.
Southern Ontario:
Scattered showers and thunderstorms are likely to develop across Eastern and Northeastern Ontario beginning between Sudbury and North Bay. These thunderstorms will continue to develop and move south extending from Huntsville, Haliburton, and Peterborough through to the United States and Quebec borders. Additional thunderstorms are possible along the lake breeze off of Lake Erie. Isolated severe thunderstorms are possible east of a line which extends from Napanee through to Bancroft and Powassan.
Areas marked in blue or with a '1' can expect non-severe thunderstorms with rainfall totals less than 30mm, wind gusts between 40 and 70km/h and small hail. Areas marked in green or with a '2' can expect some isolated severe thunderstorms with rainfall totals near or over 50mm, gusty winds between 70 and 90km/h and moderate to briefly large hail in the range of 1 to 2cm, briefly 2.5cm.
The strongest storms are likely east of a line which extends from Kingston through to Pembroke. There is a non-zero tornado risk in this region. An isolated non-zero tornado risk also extends from Macdoc and Bancroft eastward. An isolated severe thunderstorm may also be possible along the lake breeze off of Lake Erie due to training storms could possibly produce rainfall totals near or over 50mm.
Northern Ontario:
Scattered showers and thunderstorms are likely to develop in the Sudbury/Temagami/North Bay region. The risk is low for thunderstorm development in this region, but, if they develop, they do pose a risk for being isolated severe. Isolated non-severe thunderstorms are possible further north towards Temiskaming Shores but this is still questionable.
Areas marked in blue or with a '1' can expect non-severe thunderstorms with rainfall totals less than 25mm, wind gusts between 40 and 60km/h and small hail. Areas marked in green or with a '2' can expect some isolated severe thunderstorms with rainfall totals near or over 50mm, gusty winds between 70 and 90km/h and moderate sized hail in the range of 1 to 2cm.
There will be another forecast posted later this afternoon/early evening for significant weather in Manitoba which may extend into Northwestern Ontario.
Quebec:
Widespread showers and thunderstorms are likely to develop across much of Southern Quebec with the risk of some isolated to scattered severe thunderstorms. Non-severe showers and thunderstorms are likely from the Labrador border through to Mingan and Cloridorme on the east side and towards Lac Hobier and Desmaraisville on the west side. The non-severe risk also includes the Magdelan Islands. Isolated to scattered severe thunderstorms are possible from Lac Pipmuacan south through to Montmagny and the Maine border on the east side and through to Obedjiwan and Angliers on the west side. Everything in between may also see severe thunderstorms.
Areas marked in blue or with a '1' can expect non-severe thunderstorms with rainfall totals less than 30mm, wind gusts between 50 and 70km/h and small hail. Areas marked in green or with a '2' can expect some isolated severe thunderstorms with rainfall totals near or over 50mm, gusty winds between 70 and 90km/h and moderate to briefly large hail in the range of 1 to 2cm, briefly 2.5cm. There was some question to whether or not we should upgrade the risk to a moderate or '3' risk but we have gone against this due to the scattered nature of these storms.
There is a non-zero tornado risk extending from Lac McLennan and Lac Devenyns through to the Ontario border.