A combination of rainfall, warmer temperatures and melting snow expected for Toronto has authorities warning residents to avoid or exercise caution around streams and rivers.

The Toronto and Region Conservation Authority issued a statement Tuesday morning advising of higher-than-normal water levels that could create dangerous conditions near bodies of water.

Rainfall in the Greater Toronto area is expected in the range of 10 to 15 millimetres Tuesday, with the possibility of higher amounts in areas affected by a thunderstorm moving in sometime late in the afternoon.

The TRCA advisory -- which will be in effect through Thursday -- also encourages parents and guardians to alert children of the dangers and monitor their activities.

Toronto woke up to fog and light drizzle early Tuesday morning.

After several days of frigid temperatures, snowfall and freezing rain, the mercury is expected to reach a high of 5 C, Environment Canada predicts. The thunderstorm is expected to move in during the late afternoon and early evening hours, and remain past midnight. Temperatures could rise to a balmy 10 C by Wednesday morning.

Meanwhile, Environment Canada has issued freezing rain alerts for a large swath of Southern Ontario.

A low pressure system from Colorado will bring freezing rain to Central and Eastern Ontario and will likely last into the evening and overnight in the Ottawa Valley, the national weather agency said.

Most areas are expected to see one to three millimetres of freezing rain, with the Ottawa Valley possibly receiving as much as five millimetres.

Due to the freezing rain, untreated roads could become icy and treacherous, and motorists in the affected areas are being advised to be cautious and allow for extra travel time.