Oshawa and Pickering residents should prepare for periods of rain and possible thunderstorms on Tuesday, July 28, as the Durham thunderstorm risk brings unsettled conditions, humid air and stronger winds to the region.
Environment Canada’s updated 5 a.m. forecast calls for showers with a risk of a thunderstorm in both cities. Local rainfall amounts of 10 to 15 millimetres are expected during the day, with another 5 to 10 millimetres possible Tuesday night. This means parts of Oshawa and Pickering could receive approximately 15 to 25 millimetres of rain before conditions begin improving.
Earlier regional weather reports warned that some parts of southern Ontario could receive totals approaching 60 millimetres. However, the latest city-specific forecast for Durham Region shows lower expected amounts. Rainfall can still vary considerably during thunderstorms, and isolated neighbourhoods may receive more rain if a heavier storm passes directly overhead.
The daytime high is expected to reach 24 C, with the humidex making it feel closer to 30. The UV index is forecast at 3, which Environment Canada classifies as moderate. Cloudy skies and showers are expected to continue through much of the day.
Drivers should use additional caution during heavier rain. Sudden downpours can reduce visibility, create slippery roads and cause water to collect in low-lying areas or on streets with poor drainage. Motorists should slow down, leave more space between vehicles and avoid travelling through flooded sections of roadway.
People with outdoor plans should also monitor changing conditions. Thunderstorms can develop or intensify quickly, and lightning may occur even when the centre of a storm appears to be some distance away. Anyone who hears thunder should move indoors or take shelter inside a fully enclosed vehicle until the storm has passed.
Tuesday night will remain unsettled, with showers and a continued risk of thunderstorms. North winds are expected to reach 30 kilometres per hour, with gusts of up to 50 kilometres per hour. The overnight low will be around 17 C in both Oshawa and Pickering.
Residents may want to secure patio umbrellas, lightweight furniture, recycling containers and other loose outdoor items before stronger gusts arrive. While the forecast does not indicate widespread destructive winds, objects left unsecured could be moved or damaged during a stronger gust.
Conditions will remain changeable on Wednesday. Environment Canada is forecasting a mix of sun and cloud with a 60 per cent chance of showers and another risk of a thunderstorm. The high is expected to reach 26 C, with a humidex near 31. Skies are forecast to clear Wednesday night as temperatures fall to about 15 C.
More stable weather should return Thursday. The current forecast calls for sunshine and a daytime high of 27 C, followed by clear skies and an overnight low near 15 C.
The Durham thunderstorm risk remains important for commuters, outdoor workers and anyone attending activities across Oshawa or Pickering. Residents should continue checking official forecasts and weather alerts because rainfall amounts, storm timing and wind conditions may change as the system moves through southern Ontario.
