MADISON, Wis. -- Here comes the water.

The National Weather Service has issued a flood warning for portions of the Fox River and is keeping a close eye on the Mississippi.

The agency said the Fox near New Munster was nearly a foot above flood stage early Thursday. Water is approaching some homes in Kenosha County, but the river is expected to drop below flood stage by early Saturday.

The Mississippi near Wabasha, Minn., meanwhile, is expected to rise above flood stage by Monday morning and reach nearly a foot above flood stage by next Thursday, affecting low-lying areas.

Wisconsin Emergency Management spokeswoman Lori Getter said the city of Prescott has begun sandbagging efforts.

The latest forecast for the rise of the St. Croix River during the spring floods could make for tense week in Stillwater.

The Thursday afternoon update from the National Weather put the river at 83 feet, but also predicts a steady rise to flood stage of 87 feet by Tuesday and nearly 88 feet by Thursday.

Shawn Sanders, the city's public works director, said that's a foot higher than the previous forecast and triggers an overhaul of the city's flood fighting plan.

The city had already lined up 2,000 feet of concrete barriers to protect downtown, but he says now they will need to be covered with gravel to hold back more water.

If the river reaches 88 feet, the Stillwater lift bridge will be closed, cutting off a well-traveled route to western Wisconsin.