Durham Region could face another round of potentially severe weather Tuesday as forecasters warn that thunderstorms capable of damaging winds, large hail and heavy rainfall may develop across parts of southern Ontario.
The Durham storm risk comes after a wet Monday that already brought substantial rainfall to Pickering, Oshawa and surrounding southern Durham communities.
Environment Canada issued a special weather statement Monday for Pickering, Oshawa and southern Durham, warning that rainfall totals could reach 30 to 50 millimetres, with localized amounts exceeding 50 millimetres.
Attention is now turning to Tuesday, Sept. 1, when conditions across the Greater Toronto Area and other parts of southern Ontario could become favourable for severe thunderstorms.
Damaging winds and large hail possible Tuesday
Environment Canada’s thunderstorm outlook indicates that some storms developing Tuesday afternoon and evening could become severe.
The strongest storms in the broader southern Ontario risk area could produce wind gusts reaching 100 km/h, hail as large as four centimetres and heavy downpours of 20 to 40 millimetres.
Those are potential maximum storm hazards rather than a prediction that every community in Durham Region will experience those conditions.
Forecasters have emphasized that confidence remains low regarding exactly where the strongest thunderstorms will form.
Residents should therefore continue monitoring updated local forecasts, watches and warnings as Tuesday approaches.
Durham forecast turns warmer and more humid
The local forecast for Pickering, Oshawa and southern Durham calls for a significant increase in temperature Tuesday.
Environment Canada expects a high near 28 C, with the humidex making it feel closer to 36.
There is a 40 per cent chance of showers during the morning before conditions become warmer and increasingly humid.
The chance of showers rises again to 60 per cent Tuesday night.
Those conditions come after Monday’s heavy rainfall, when showers and embedded thunderstorms prompted a special weather statement across southern Durham.
Environment Canada warned that water could pool on roads and in low-lying areas because of the amount of rainfall.
Severe storms could continue into Wednesday
The unsettled pattern may not end Tuesday evening.
Environment Canada’s broader outlook indicates that severe thunderstorms could continue overnight into Wednesday in parts of southern Ontario.
Potential hazards could again include damaging wind gusts, large hail and localized heavy rain.
Wednesday’s Durham forecast currently calls for cloudy conditions with a chance of showers, although forecasts may change depending on the timing and movement of Tuesday’s storm system.
Outlook is not yet a severe thunderstorm warning
Residents should understand the difference between a thunderstorm outlook and a weather alert.
An outlook identifies areas where atmospheric conditions could support thunderstorms in the coming period.
It does not mean a severe thunderstorm watch or warning is currently in effect for every community shown in the outlook area.
Watches are generally issued when conditions are favourable for severe storms, while warnings are issued when severe weather is occurring or considered imminent.
Because the exact location of Tuesday’s strongest storms remains uncertain, residents should watch for more targeted alerts from Environment Canada.
Durham residents urged to monitor conditions
The Durham storm risk follows an already wet start to the week, increasing concern about additional rainfall in areas where the ground and drainage systems may already be dealing with substantial water.
Drivers should be prepared for sudden reductions in visibility, ponding on roads and difficult travel if heavy thunderstorms develop.
Residents should also secure loose outdoor objects and be prepared to move indoors if severe-weather warnings are issued.
Forecast details are expected to become clearer as the storm system approaches Durham Region Tuesday.
