Environment Canada has issued a special weather statement, advising residents in Hamilton and Niagara Region of the possibility of heavy rain.
The weather agency says showers and thunderstorms are expected to move across the area late Tuesday morning into the early afternoon.
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It says the storm will have the potential to produce heavy rainfall accumulations in the 20- to 40-mm range.
After this initial band of precipitation, additional showers and thunderstorms will be possible late Tuesday afternoon into the evening.
Apart from the rain, Environment Canada is forecasting Tuesday to be hot and humid with the high expected to reach 29 C, which could feel like 34 with the humidity.