Rainfall warning in effect for Ottawa, eastern Ontario

Environment Canada says a rainfall warning bringing 50 to 100 millimetres of rain is in effect for eastern Ontario and Ottawa starting Thursday night.

The weather agency calls for heavy rain, at times, through Friday. 

"A low pressure system interacting with the remnants of Tropical Storm Debby is expected to give heavy rainfall for eastern Ontario tonight through Friday. Rain will taper off Friday night," says the weather agency on its website.

Residents are asked to familiarize themselves with information about flooding by consulting their local Conservation Authority or Ontario Ministry of Natural Resources and Forestry by visiting the following website: Ontario.ca/floods.

Tropical Storm Debby continued to swirl over Georgia and Carolinas on Wednesday. Some coastal cities have received more than 30 cm of rain.

"Even without Debby, the system would've brought us some rain tomorrow," David Phillips, senior climatologist for Environment Canada, told CTV News Ottawa Thursday.

"But now with the abundance of precipitation or moisture from Debby, we're going to see significant rain."

Phillips says the heavier rain is expected tomorrow, noting that Friday's heavy downpours could be record-breaking.

The current record for most rain on Aug. 9 is 41.4 mm, set in 1959.

"Ottawa is used to tornadoes, but we don't often see remnants of hurricanes in the Ottawa area," Phillips added.

Weather forecast

It's going to be mainly sunny Thursday morning in Ottawa. A high of 24 C – humidex 30 -- and increasing cloudiness early this afternoon are in the forecast. Showers are expected to begin this evening, with a risk of thunderstorm overnight and late this evening. The capital is expected to have a low of 17 C and to receive 15 to 25 mm of rain tonight, according to Environment Canada.

A high of 24 C and heavy rain with a risk of a thunderstorm are in the forecast for Friday -- 50 to 70 mm of rain is expected for Ottawa. A low of 17 C and rain are in the forecast for the night.

Saturday will be sunny with a high of 25 C. Rain is expected on Sunday and Monday.

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The average temperatures for this time of year are a high of 25.9 C and a low of 15 C.