SUDBURY -- As if extreme heat wasn't enough, a severe thunderstorm watch has been issued for areas near Greater Sudbury and North Bay.

Also included in the watch are West Nipissing, Chapleau, Gogama, Elliot Lake, Ranger Lake, Kirkland Lake, Temiskaming Shores and Temagami.

"Conditions are favourable for the development of severe thunderstorms this afternoon," Environment Canada said Thursday afternoon.

"Primary threats from these thunderstorms include wind gusts up to 100 km/h and hail size up to quarter size."

The thunderstorm watch is in addition to the heat warnings covering northeastern Ontario that have been extended into the weekend. Highs in some areas today are expected to reach 34.

A severe thunderstorm watch is issued when atmospheric conditions are favourable for the development of thunderstorms that could produce large hail, damaging winds and torrential rainfall.

"Strong wind gusts can toss loose objects, damage weak buildings, break branches off trees and overturn large vehicles," Environment Canada said. "Intense lightning is likely with any thunderstorm that develops. Lightning kills and injures Canadians every year. Remember, when thunder roars, go indoors!"

The Office of the Fire Marshal and Emergency Management recommends that you take cover immediately if threatening weather approaches.

To report severe weather, send an email to or tweet reports using #ONStorm.

For more information on protecting yourself, click here.