textproduct: Central Illinois

KEY MESSAGES

- Light winds, clear skies, and temperatures dropping below 36 degrees overnight tonight will result in frost development over central and southeastern IL tonight. A Frost Advisory is in effect from 1AM to 8AM tonight/tomorrow morning. Take precautions for sensitive vegetation.

- Temperatures dropping at or below freezing tomorrow night, resulting in a Freeze Watch for tomorrow night. Take precautions for sensitive vegetation.

- Daytime temperatures will rebound into the upper 70s to mid 80s by mid week ahead of the next low pressure system late week.

DISCUSSION

Issued at 210 PM CDT Sat Apr 18 2026

[COLDER TEMPERATURES] --- The main concern in the near term is the frost potential tonight and the frost/freeze potential for Sunday night. Temperatures tonight will drop down to 33-38 degrees, with clear skies and light winds. That supports the development of frost overnight tonight, so a Frost Advisory has been issued. Tomorrow night has a 40-60% chance of below 32 degrees for lows along/northeast of a Beardstown to Terre Haute line, based off the HREF. A Freeze Watch has been issued for tomorrow night. Being in the growing season now, precautions should be taken to protect sensitive vegetation tonight and tomorrow night.

[TEMPERATURES REBOUND] --- Cool temperatures today and tomorrow will be reinforced for Monday with a secondary cold front moving through during the day Sunday. Temperatures during the day through Monday will be slightly below normal, upper 50s to low 60s. Winds will become southerly late Monday and will increase, bringing WAA back into central and southeastern IL. By Tuesday, temperatures will have rebounded to above normal, upper 70s to mid 80s, for Tuesday into Friday ahead of the next cold frontal passage late week.

[PRECIPITATION] --- For the extended period, the forecast is widely dry through the first half of the new week. There looks to be another potent low pressure system move through late week. It could bring more rainfall and thunderstorms. At this time, severe risk isn't clear, but the CSU machine learning suggests a 5% risk for severe weather. We will continue to monitor as we enter the new week.

AVIATION /06Z TAFS THROUGH 06Z MONDAY/

Issued at 1223 AM CDT Sun Apr 19 2026

A weak trough will dig across the region Sunday afternoon. Ahead of the trough, a modest WSW/W breeze will be in place with gusts to around 20 kt developing mid morning. Winds will veer to the northwest behind the trough with gusts picking up more into the mid 20kt range. High pressure will spread across the upper Midwest Sunday evening causing winds to veer out of the N to NE Sunday evening and drop back below 10 kt. VFR conditions are expected through the period.

ILX WATCHES/WARNINGS/ADVISORIES

Frost Advisory until 8 AM CDT this morning for ILZ027>031- 036>038-040>057-061>063-066>068-071>073. Freeze Watch from late tonight through Monday morning for ILZ027>031-036>038-041>046.