textproduct: Central Illinois

KEY MESSAGES

- Rain chances will be highest late this afternoon into early evening, then again Friday night. A few of the storms will be on the strong side, but the main threat of that will be south of I-72.

- Locally heavy rain will result in the potential for areas of flooding, with the focus shifting more into areas south of I-72 by Friday night.

- Temperatures remain typical for July. While a warming trend takes place next week, humidity levels will make it feel less oppressive than last week's heat wave.

UPDATE

Issued at 921 PM CDT Thu Jul 9 2026

Showers and storms have quited down for now, but lots of leftover outflow boundaries in the area. These could be focus for more showers and storms later tonight as the low level jet increases during the overnight hours. Believe the main focus will be along and south of I-72/Danville so have adjusted pops to reflect that trend. Adjusted pops for tomorrow as well since any boundaries should be in southeast CWA through the morning. Things will begin to increase again as the boundary in northern IL/IA will slide south in our north and could be the focus for more showers and storms tomorrow afternoon and evening. Update should be coming shortly.

DISCUSSION

Issued at 116 PM CDT Thu Jul 9 2026

Short Term (through Saturday):

Prominent MCV from the decaying convection across Missouri is about to cross the Mississippi River south of Pittsfield. Despite a fair amount of cirrus blowoff, MLCAPE's of 1000-1500 J/kg have allowed scattered storms to develop over the last hour across eastern Illinois. Recent Day1 convective outlook shifted the risk areas a little further south and are mainly concentrated south of I-72. Greatest downdraft CAPE is expected preceding the anticipated convection across central Illinois, though there remains some uncertainty with the extent of strong/severe storms. In general, much of the shower/storm activity is expected through sunset. While development of another MCS across Missouri is expected this evening, most of the high-res guidance keeps this to our southwest.

A front across Iowa and southern Wisconsin is expected to only slowly drift southward the next couple days. Additional convective complexes are expected to ride along the boundary Friday night, and highest rain chances remain over the south half of the forecast area during this time. East-west upper troughing will set up during the weekend, keeping the frontal movement on the slow side. However, by late Saturday night, it should finally be near the Ohio River, ending the rain threat.

Long Term (Sunday through Thursday):

Little change in the forecast for next week. A sprawling upper high will dominate a large portion of the CONUS to start the week, before the ridging amplifies near the Plains by midweek. This pattern will result in seasonably warm temperatures near 90 degrees in our area, though with the Gulf cut off, humidity levels should not get as rough as last week's heat wave. Still, heat index levels of 95-100 degrees are likely Tuesday-Thursday.

As the upper ridge establishes itself, we'll be on the periphery of a northwest flow, which can be favorable for MCS activity. Right now, that activity looks to be more across the Great Lakes region, so a dry forecast will be maintained in the extended period.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1202 AM CDT Fri Jul 10 2026

Areas of MVFR ceiling and visibility are expected to develop over central IL later tonight, and persist through 13-14z. There are low probabilities of IFR conditions during this period. The other aviation issue will be scattered TSRA Friday afternoon and evening. Due to timing and coverage issues, kept mention to PROB30 for now. Winds predominantly light/variable through the forecast.

ILX WATCHES/WARNINGS/ADVISORIES

None.