Ottawa won't entirely escape a snowstorm blowing through southern Ontario, as Environment Canada says the city can expect another 15 centimetres of snow overnight Thursday and into Friday.

Get the latest updates on your weather from CBC Ottawa climatologist Ian Black.

Environment Canada issued a special weather statement for Ottawa and the surrounding region, saying a snowstorm threatens the region Thursday night and Friday.

The caution comes after the national agency issued a winter storm warning for much of southern and parts of eastern Ontario, extending from London to Kingston, and including Toronto.

While Ottawa can expect about 15 cm, the Kingston and Tweed areas can expect between 15 to 25 cm of snow, according to CBC Ottawa climatologist Ian Black.

An Ottawa city official said the fact the majority of snow will fall during the day Friday is a complicating factor.

"It's not coming at the best time with the morning and afternoon commute," said Jason Staniforth, area manager of core roads.