“An active weather pattern will begin tomorrow, with multiple opportunities for thunderstorms in the region through Wednesday evening,” National Weather Service (NWS) Chicago said Saturday afternoon. “Some of these storms may be severe and produce heavy rainfall, which may lead to instances of flash flooding.” The storms are expected to first sweep McHenry County from 8 a.m. to 11 a.m. Sunday before entering Lake County shortly after. The additional round of storms is expected Sunday evening into Monday morning, but the exact timing is yet to be determined. The Chicago area is currently at severe weather threat level 2 of 5 as of Saturday afternoon.