Area Forecast Discussion

KEY MESSAGES

- Temperatures dropping into the low to mid 30s overnight, will result in more widespread frost development. A Freeze Warning and a Frost Advisory is in effect from 1AM-8AM Monday morning. Precautions should be taken to protect sensitive vegetation tonight. - A warming trend will be in place after tonight. 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 203 PM CDT Sun Apr 19 2026

[COLDER TEMPERATURES] --- The main concern in the near term is the frost/freeze potential for tonight. Temperatures tonight will drop down to 30-36 degrees, with clear skies and light winds, north of I- 70. Tomorrow night has a 40-70% chance of below 32 degrees for lows along/northeast of a Beardstown to Terre Haute line, based off the HREF. A Freeze Warning has been issued for tonight for Fulton to Edgar Counties and north, where the probabilities are highest. A Frost Advisory is in effect for tonight south of the Freeze Warning. Being in the growing season now, precautions should be taken to protect sensitive vegetation tonight.

[TEMPERATURES REBOUND] --- Cool temperatures today will be reinforced for Monday as a weak cold front travels south across central IL this afternoon. Temperatures during the day through Monday will be slightly below normal, upper 50s to mid 60s. Winds will become southerly late Monday and will increase in speed, bringing WAA into central and southeastern IL. Temperatures will have rebounded to above normal, upper 70s to mid 80s, for Tuesday into Friday ahead of the next cold frontal passage late in the week.

[PRECIPITATION] --- For the extended period, the forecast is widely dry through the first half of the new week. There are some low end (15-30%) pops for Tuesday night as WAA and moisture return increases ahead of the late week system. The next potent low pressure system moves through late week. It could bring more efficient rainfall and severe thunderstorms. At this time, severe risk isn't clear, but the CSU machine learning suggests a 5% risk for severe weather. Right now based off the long range models, the associated front that would deliver the storms would be moving in at an unfavorable time for severe weather (overnight). We will continue to monitor as we enter the new work week.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1209 AM CDT Mon Apr 20 2026

High pressure over the region will shift towards the Upper Ohio Valley by Monday evening. Light north winds currently in place will become variable overnight, then eventually set up out of the south behind the departing ridge axis. VFR conditions are expected through the period.

ILX WATCHES / WARNINGS / ADVISORIES

Freeze Warning until 8 AM CDT this morning for ILZ027>031- 036>038-041>046-055-057. Frost Advisory until 8 AM CDT this morning for ILZ040-047>054- 056-061>063-066>068-071>073.