textproduct: Central Illinois

KEY MESSAGES

- Wind gusts of 30-40 mph are likely this afternoon, with the strongest winds being west of I-57.

- Much cooler weather will settle into the region through the weekend, resulting in areas of frost both Saturday and Sunday mornings. There is a 40-60% chance of temperatures dropping below 32 degrees northwest of the IL River tonight/Saturday morning and a 30-50% chance east of I-55 Saturday night/Sunday morning.

DISCUSSION

Issued at 327 PM CDT Thu Oct 15 2026

A cold front has moved through the area but the 500mb trough will rotate through the area today, bringing instability showers to the entire area this afternoon. The bulk of the showers will diminish after sunset but some could linger in far eastern parts of the CWA as the flow becomes more northerly and scattered showers are expected to drop south of Lake Michigan to along the IL/IN border during the evening.

Cold air advection is occurring behind the front, tightening the pressure gradient. This is bringing gusty winds to the area early this morning. Wind gusts over 30 mph have already occurred in some spots and gusts shows 80-90% chance that gusts over 30 will continue through the day. In fact, the HREF shows a 40-60% chance of gusts over 35 mph east of I-55 during the afternoon and early evening hours. Winds will then decrease in the west during the evening but not taper off in the east until around midnight.

Cooler, fall like temperatures will advect into the area behind the departing cold front this weekend. Highs today and Saturday will be in the 50s, with lows in the mid to upper 30s both Sat and Sun morning. With skies becoming clear tonight and winds becoming much lighter overnight, frost is expected to develop across west central and parts of central Illinois late tonight. The HREF is showing a 40-60% chance of temperatures dropping below 32 degrees northwest of the IL River late tonight/Sat morning, so some low spots could see a light freeze. Frost is possible again Sunday morning, mainly in areas east of I-55 where the HREF is showing a 30-50% chance of temperatures dropping below 32 degrees. Because of the frost potential tonight, a frost advisory has been issued for areas west of a Bloomington to Decatur to Shelbyville line. Another frost advisory will likely be needed east of I-55 Saturday night. Temperatures will begin to warm starting Sunday, reaching into the 60s. The rest of the extended forecast, Monday through Friday, looks to be above normal with highs in the 70s to around 80, especially Thursday and Friday. Dry weather is also expected through the extended period.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 610 AM CDT Fri Oct 16 2026

VFR conditions will start all sites, but MVFR clouds around 2.5kft will advect back into the area from the northwest this morning, as the 500mb trough rotates into the area. This trough will bring gusty northwest winds, scattered showers and lower cigs. So, will have cigs at all sites below 2kft and vcsh. Will also have a PROB30 for showers possibly hitting sites with 5sm and cigs below 1kft. This will last into the afternoon but end at or prior to 00z. During evening cigs will improve to VFR at all sites and VCSH will end. Late tonight clouds will dissipate and skies should become clear or mostly clear. Winds will be northwest through most of the period, but become more northerly during the evening and overnight hours. Winds will be sustained at 15-18kts with gusts of 30kts possible. Speeds will diminish in the evening, but remain breezy, around 15-20kts, but then get lighter more late tonight.

ILX WATCHES/WARNINGS/ADVISORIES

Frost Advisory from 1 AM to 9 AM CDT Saturday for ILZ027>031- 036-037-040>042-047>052.