Heavy rain, flash flooding possible across Northern Illinois Monday

Mother's Day was not only filled with love for all the incredible moms, but it was also filled with summer-like warmth. In the end, the Rockford Airport peaked at a whopping 84°, marking the fourth day this year with a high at or above the 80° mark. 

It also ties April 14th for the warmest day of 2024. As we begin the new work week, the focus turns from the weekend warm up to heavy rain potential as our next storm system slowly approaches.   

There is some good news. Rain chances will stay away for the morning drive and for the hours leading up to midday. This will allow temperatures to quickly surge into the mid to upper 70s.

From there, multiple waves of showers and storms will interact with a nearly-stationary warm front, increasing the potential for flash flooding. This is mainly for areas along and south of I-88 where 1.5" or more of rain could fall, hence the Slight Risk (15% chance) for excessive rainfall. 

Due to the slow-moving nature of this storm system, showers chances will remain in place overnight and into the first half of Tuesday. All in all, around 0.5″-1.5″ of rain is to be expected outside of this narrow swath mentioned above. 

Tuesday will be the coolest day of the next 7 as a northeasterly breeze will limits afternoon highs to the low 60s. Wednesday into the first half of Thursday looks dry, but rain and possible storm chances make a return Thursday night into Friday.