Heavy rain on Sunday may cause flooding in portions of the eastern Dakotas, much of Minnesota and northern Iowa. A clash of air masses will be the culprit for all this rain. Warm, moist air being shoved northward will collide with cool Canadian air draining southward from Ontario. When this happens, the warm, moist air is forced to rise, form clouds, and drop some of its moisture in the form of rain.

Obviously, this portion of the country has seen more than its share of flooding problems this year, and this particular scenario of heavy rain is not needed. If you live in or are visiting this area, please keep tuned to the various media outlets that AccuWeather can be reached for updates on this dangerous weather situation.

Story by AccuWeather.com Meteorologist Mark Paquette.