Snowflakes started falling shortly before 9 a.m. in the city. Three to four inches are forecast. Northern and western suburbs could get half a foot.

The snow will mix with sleet late in the morning, as temperatures hover near freezing. Things could get very slippery, so be careful and allow extra time to get anywhere.

At some point rain will wash it all away, but possibly not till tonight.

“It could be two messy rush hours,” Joseph Esposito, the head of the city’s Office of Emergency Management, said.

If you’ve grown skeptical of snow forecasts, we understand. Since the surprise November storm, the city has seen only 1.1 inches of snow. The hyped-up mid-January storm delivered a grand total of 0.7 inches.

But after getting caught off guard in November, officials are taking no chances. Mr. Esposito said he was ready for a foot of snow.