Chance of thunderstorms across the Chicago area overnight into Saturday forenoon

Updated 10:30PM CST…

Thunderstorms may reoccur later tonight and early Saturday morning as low pressure passes to the south. Best chance of thunderstorms will be south of Interstate-80 into central Illinois (see thunderstorm probability map below). The threat of thunder will likely continue into Saturday forenoon before the cold air sweeps into our area from the north and west with rain possibly Changing over to wet snow/flurries as temperatures drop back into the 30s.

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Updated 4PM CST…

Updated thunderstorm outlook still has the Chicago area in a 10% probability of t-storms within 12 miles of a given location tonight. Note probability increases to the south with a 40% chance area across central Illinois (See map below).

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Updated 11AM CST…

The forecast for a 10% chance of thunderstorms has been extended through the overnight hours until 6AM CST Saturday morning – see maps for 6PM to 10PM CST and 10PM to 6AM CST added below.

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There is about a 10% chance you could hear thunder later this afternoon into the evening hours across northern Illinois into northwest Indiana. The National Storm Prediction Center has the Chicago area in the center of a 10% chance of thunderstorms within 12 miles of a given locations between 3 and 6PM this afternoon (see map below).

With low pressure strengthening in the central and northern plains and its associated cold front headed our direction, crossing the Mississippi River before midnight, the probability of thunderstorms will most likely increase this evening. A southerly low-level jet will see winds just above the surface hit 35 to 45 miles per hour with a strengthening westerly upper-level jet stream over 100 miles per hour nosing into Illinois. The combination of increasing moisture and instability will enable convective storm development to our west, spreading the storms into our area – follow the precipitation movement on the radar mosaic below.

Thunderstorm probability map 10PM CST Friday to 6AM CST Saturday…

Current Weather Radar Mosaic…

Central Great Lakes sector loop