Weather officials are warning of the threat of periodic thunderstorms, some potentially severe, from Sunday morning through Wednesday for Lake and McHenry counties and the rest of the region.
“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 initial rounds of storms are expected Sunday morning and early afternoon.
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 strongest of storms may bring damaging winds and hail up to the size of a quarter, NWS said.
The additional round of storms is expected Sunday evening into Monday morning, but the exact timing is yet to be determined.
“The exact placement and timing remains uncertain and will depend on the evolution of morning activity, but any storms that develop will be capable of all severe hazards,” NWS said.
Officials say that storms Sunday evening into Monday specifically pose a localized flash flood threat, especially those in or near low-lying areas, fields and streams and creeks.
Periodic storms, some potentially severe, will continue afterwards and through Wednesday.
The Chicago area is currently at severe weather threat level 2 of 5 as of Saturday afternoon.
Weather officials are warning people to have multiple ways of receiving weather warnings, move indoors if there’s thunder and use caution when driving in heavy rain.