The Meteorological Authority warns of rainfall in effect in Ottawa, as the Canadian Ministry of the Environment has issued a "heavy rain" warning today and tomorrow. 

Ottawa may see rainfall of 20 to 30 mm by Friday morning. Some areas of Eastern Ontario may experience 45 mm of rain. The Canadian Ministry of the Environment said: "Heavy rainfall is expected at times. The ground, already near saturation, has little capacity to absorb more rain."

The record for the highest rainfall at Ottawa Airport is 14.4 mm, in 2005. 

The rain started overnight and is expected to continue throughout Thursday.

Friday will be cloudy with a chance of rain, with a high of 11 degrees Celsius. Saturday will be cloudy with a chance of rain.

Water levels are expected to rise. The Rideau Valley Conservation Authority warns that water levels will rise along the Rideau River watershed this week. RVCA said: "Short-term forecasts indicate the possibility of up to 40 mm of rain between Thursday, April 7 and Saturday, April 9. Snow has melted across the entire watershed."

"Although major flooding is not expected, water levels and flows in all waterways in the Rideau Valley watershed are expected to increase." The authority says that water levels in Upper Rideau Lake, Big Rideau Lake, Bobs, and Christie will continue to rise due to the rainfall.