Chicago's first summer-like day in some time could end in storms.
Models show scattered showers and thunderstorms developing west of the Fox Valley late in the afternoon with a few storms becoming severe. Storms likely will spread across the area overnight, possibly producing damaging wind, large hail, heavy rain and frequent lightning.
The National Weather Service warns a few storms may produce hail larger than an inch in diameter and winds exceeding 60 mph.
Thunderstorms are expected to start west of LaSalle to Rockford and move east toward Chicago and increasing in coverage.
Lingering storms could last into Friday morning with a few producing large hail, damaging winds and localized flooding.
Until then skies remain partly to mostly cloudy with warm, even humid conditions thanks to highs in the low- to mid-80s across most of the Chicago area.
Temperatures cool slightly on Friday to the low 70s as rain concludes in the morning. Those temps hold through much of the weekend before dipping to the mid-60s Monday and Tuesday.
Periods of showers and storms are possible on Mother's Day.