With a hot, humid and increasingly unstable air mass overhead chances of thunderstorms developing either in our area or to our west/southwest moving in our direction will be on the rise this Sunday afternoon.
The National Storm Prediction Center has already issued a mesoscale discussion describing the likelihood (60%) a Severe Thunderstorm Watch will be issued over portions of western and southern Illinois this afternoon. A strong upper-level disturbance tracking across Missouri and eventually Illinois will trigger strong to severe thunderstorms along the Mississippi River later this afternoon with the band of storms expected to move northeast. If the complex of storms holds together, it could impact our area early this evening and continue into the late overnight hours.
Below are the Thunderstorm Outlook maps depicting the chances of thunderstorms within 12 miles of any given location. Highest probabilities (70%-plus) look to be in Missouri and west-central Illinois later this afternoon. The Chicago area (northeast Illinois into NW Indiana) is in the 40 to 60% (blue-shaded) category until later this evening.