A Durham Thunderstorm Risk is part of a broader unsettled weather outlook across southern Ontario, with isolated storms capable of producing strong winds, hail and locally heavy rainfall on Monday, Aug. 10.
Environment Canada’s thunderstorm outlook indicates that much of southern Ontario could experience thunderstorms Monday afternoon and evening, although the likelihood and severity vary by location.
Durham Region is within the broader Greater Toronto Area zone where isolated thunderstorms are possible.
Strong winds and hail possible Monday
For the Greater Toronto Area and other parts of southern Ontario, Environment Canada says there is low confidence regarding exactly where thunderstorms will develop.
However, any storms that do form could become strong.
According to the forecast, thunderstorms could produce wind gusts reaching 90 km/h along with hail measuring as much as 2.5 centimetres.
Locally, rainfall amounts could reach approximately 30 millimetres.
The risk extends across a large portion of southern Ontario, including the GTA, Hamilton, Niagara Region, London and Windsor.
Because thunderstorms can develop in isolated areas, conditions could vary considerably from one community to another.
Eastern Ontario faces higher storm confidence
Environment Canada has indicated a greater likelihood of thunderstorms in areas farther east and north.
That zone includes communities such as Prince Edward County, Kingston, Huntsville and Ottawa, extending north toward Sudbury.
Scattered thunderstorms are expected in those areas, with the potential for wind gusts of up to 90 km/h.
Hail could range from approximately two to four centimetres in diameter.
Local rainfall totals could reach 40 millimetres.
Strong storms in those areas could also result in downed trees and power outages.
What Durham Region could experience
While Durham is not identified as being within the zone with the highest confidence for storm development Monday, residents should still be prepared for rapidly changing weather.
The Durham Thunderstorm Risk includes the possibility of isolated storms capable of bringing powerful wind gusts and hail.
Heavy rainfall may also occur over short periods if a thunderstorm develops over a particular community.
Residents travelling across Durham or elsewhere in the GTA should remain aware that weather conditions can differ significantly over relatively short distances during periods of thunderstorm activity.
Thunderstorm risk continues Tuesday
Unsettled weather could continue into Tuesday, Aug. 11, although the thunderstorm risk is expected to become less widespread.
Environment Canada’s outlook indicates scattered thunderstorms are possible in several parts of Ontario.
Areas identified in Tuesday’s outlook include extreme southwestern Ontario, portions of eastern Ontario including Ottawa, and sections of northern Ontario.
Those thunderstorms could produce localized rainfall amounts of up to approximately 25 millimetres.
Based on the outlook provided, the widespread southern Ontario storm risk seen Monday is not expected to continue at the same level Tuesday.
Residents should monitor changing conditions
Thunderstorm outlooks identify areas where atmospheric conditions may support storm development, but they do not mean every community within an identified area will experience severe weather.
The exact location and strength of individual storms can change as weather systems develop.
With the Durham Thunderstorm Risk in place Monday, residents should monitor updated Environment Canada forecasts and any watches or warnings that may be issued as conditions evolve.
Drivers should also be prepared for reduced visibility and difficult road conditions during periods of heavy rainfall, while strong wind gusts and hail could create additional hazards.
The main period to watch in Durham Region is Monday afternoon and evening, when isolated thunderstorms could develop across the GTA and surrounding parts of southern Ontario.
