A big spring storm will cause big trouble across the northern and central Plains and the Rockies today and Monday.

A low-pressure system is moving out of the Rockies today and spreading to the northeast. Fed by a strong southerly flow from the Gulf, the WeatherRadar shows heavy rain and thunderstorms developing across the northern and central Plains. The downpours will reach into the western Great Lakes later Monday.

Several inches of rain are expected through Tuesday for the upper Mississippi Valley, increasing the risk of localized and urban flooding around the Twin Cities northeastward into Duluth, Minn., and Green Bay, Wisc.

On the back side of this system, the TemperatureRadar shows arctic air plunging across the northern and central Rockies.

This will be just cold enough to produce late-season snow across the central and northern Rockies and the Front Range. This heavy and wet snow could cause slick roads and local power outages west of Denver.