Another winter storm is expected to dump more rain and snow on Chicago tonight.

Paul Merzlock is with the National Weather Service in Chicago. He says a winter weather advisory is in effect for Cook and DuPage Counties.

“It’s bringing snow across Minnesota and southwestern Wisconsin right now,” he said. “And that’s forecasted to bring snow into the area later this evening and overnight and that’s when most of the accumulation is expected.”

Four inches of snow or more could build up by Tuesday morning. Merzlock says runoff from rain could cause flooding in some areas. The National Weather Service has issued flood warnings for Lake and Will Counties in Illinois. Cook County is under a flood advisory due to rising waters in the Des Plaines River.

Merzlock said the accumulation from tonight’s storm shouldn’t affect flood stage levels, but another weather system that’s expected to hit Wednesday night could bring rain and more snow.

“It’s a little bit early to tell right now,” he said. “But that one could aggravate the flood situation on area rivers, bringing in more significant precipitation toward the end of the week right around Wednesday night, Thursday time frame.”