Heavy rain came down over southern Wisconsin and northern Illinois early Sunday morning with the Rockford Airport receiving 1.82 inches of rain! Skies have stayed cloudy through much of the afternoon and an isolated shower or two can’t be ruled out through Sunday evening. More heavy rain, however, is possible Monday afternoon and evening leading to the potential risk for localized flooding.
Southwest winds Sunday night will keep temperatures on either side of 70 degrees, but also pull in quite a bit of Gulf moisture. A system moving over top a very strong ridge of high pressure centered over Texas will move into Iowa Monday morning and then into northern Illinois Monday afternoon. As it does, a warm front will begin to pull north but may fall just shy of the immediate Stateline and settle near the I-80 and I-88 corridor. South of the boundary instability (energy in the atmosphere) will build during the afternoon. This could lead to explosive thunderstorms late in the afternoon and evening. As it looks right now (Sunday evening) the greatest threat for severe thunderstorms will be outside of the area and mostly south of I-80. However, I think we’ll need to keep an eye on parts of Whiteside, Ogle, Lee and DeKalb counties for the possibility for a few stronger storms.
Heavy rainfall will also be a concern with some locations receiving potentially over an inch to inch and a half of rain by Monday evening. The risk for flash flooding will likely remain where the stronger storm potential is, but a prolonged heavy rain even is possible for parts of the area which could lead to localized flooding.
Meteorologist Joey Marino and I will continue to bring you updates on the storm potential for Monday afternoon. Be sure to stay up-to-date on the latest forecast throughout the day.