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 /00Z TAFS THROUGH 00Z MONDAY/

Issued at 615 PM CDT Sat Apr 18 2026

VFR conditions will prevail the next 24 hours, with a few periods of scattered clouds near 10kft. Strong northwest winds will drop off quickly early this evening, but will begin to gust to around 25 knots again by midday Sunday.

ILX WATCHES/WARNINGS/ADVISORIES

Frost Advisory from 1 AM to 8 AM CDT Sunday for ILZ027>031- 036>038-040>057-061>063-066>068-071>073.