A tornado warning has ended for Ottawa and Gatineau, but a severe thunderstorm watch and a severe heat warning remain in both cities as of 5:20 p.m., according to Environment Canada.

The severe weather comes as thousands gather in the national capital region to celebrate Canada Day. RCMP estimate 24,000 people were on Parliament Hill alone during the 12 p.m. performance.

A tornado warning issued at 1 p.m. for the Ontario communities of Arnprior, Renfrew and Calabogie, west of Ottawa, has also ended.

Daytime temperatures are expected to reach a high of 30 C in Ottawa, which will feel more like 40 C with the humidex.