A winter storm is set to bury Ottawa with 20 to 30 cm of snow by Friday morning.

The city of Ottawa has declared a daytime winter weather parking ban from 10 a.m. to 7 p.m., and OC Transpo says the O-Train will not serve downtown stations.

Environment Canada has issued a winter storm warning for Ottawa, calling for heavy snow at times this evening and overnight.

"Peak snowfall rates of 2 to 4 cm per hour likely at times," Environment Canada said.

The snow comes after Ottawa received significant rainfall on Thursday and the temperature warmed up to 5C.  The forecast calls for snow at times heavy this evening. Low minus 11 C, with the wind chill making it feel like minus 20.

Light snow will end Friday morning, then a mix of sun and cloud with a chance of flurries. High -9C.

Snow is expected on Saturday with a high of -6C, while Sunday will see mostly cloudy skies with a chance of flurries and a high of -4C.

SIGNIFICANT WEATHER EVENT

The city of Ottawa has declared a significant weather event.

A daytime winter weather parking ban will be in effect on Friday from 10 a.m. to 7 p.m.

"During a winter weather parking ban, parking is prohibited on city streets so crews can plow easily and effectively," the city said.

"Vehicles parked on the street during a ban may be ticketed and towed. Though on-street monthly parking permit holders are exempt from this restriction when they are parked in residential parking permit zones, we encourage those who can to find off-street parking options to avoid getting snowed-in."

During a winter weather parking ban, residents can park at select OC Transpo park and rides and certain recreation centres.