textproduct: Central Illinois

KEY MESSAGES

- A broken line of showers and thunderstorms will track across central Illinois through mid-morning. The strongest cells may be capable of 40-50mph wind gusts and brief downpours.

- Freezing temperatures are expected across nearly all of central Illinois Monday night. There is a 50-70% chance of readings dropping below 30 degrees along and north of a Macomb to Tuscola line.

DISCUSSION

Issued at 315 AM CDT Sat Apr 4 2026

07z/2am surface analysis shows a 1010mb low near Galesburg with a cold front extending southwestward into the Ozarks. A broken line of thunderstorms accompanies the front. A 45-50kt 850mb jet streak is currently providing enough fuel for the storms to maintain themselves as they slowly shift eastward across the KILX CWA through mid-morning. Latest mesoanalysis reveals a weakly unstable/sheared pre-frontal environment characterized by MLCAPEs of 500J/kg and 0-6km bulk shear of around 30kt. A narrow corridor of DCAPEs on the order of 800-900J/kg is analyzed along/just ahead of the front...supporting the potential for a few sub-severe wind gusts with the strongest cells. The AWOS at Pittsfield in Pike County recently measured a thunderstorm wind gust of 43mph accordingly. Based on radar timing tools, the line of storms will reach the I-55 corridor by 4am and the I-57 corridor by around 6am. Showers will come to an end across the Illinois River Valley shortly after daybreak: however, additional showers/storms currently over southern Missouri will lift northeastward...allowing a continuation of precip along/east of I-57 through at least midday. After that, showers will gradually come to an end across the E/SE CWA during the afternoon. High temperatures will be achieved early in the morning, with NW winds gusting 25-30mph helping bring cooler air into the region for the remainder of the day. Readings will hover in the upper 40s west of the Illinois River and in the lower to middle 50s further east across the rest of the area this afternoon.

Cool and dry weather will prevail Sunday through Tuesday as upper troughing remains in place across eastern Canada into the Great Lakes. High temperatures will mainly be in the 50s and lows in the 30s...with the coolest period being Monday night into Tuesday. Confidence continues to grow that a hard freeze will occur across at least the northern half of the CWA Monday night as the 12z LREF indicates a 50-70% chance of temps dropping below 30 degrees along/north of a Macomb to Tuscola line. While the growing season has not yet gotten into full swing, some plants have emerged a couple weeks ahead of schedule this spring and may be susceptible to the freezing conditions. After that, a zonal flow pattern will bring warmer and more unsettled conditions back to the region by the end of next week. Temperatures will climb into the lower to middle 70s and rain chances will return by Thursday/Friday.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1202 PM CDT Sat Apr 4 2026

A cold front is moving across central Illinois late this morning and afternoon. Showers should end across the terminals by around 18Z, while IFR ceilings currently in place at some of the central Illinois terminals should improve to MVFR. Ceilings will gradually lift/scatter back to VFR this evening. Meanwhile, gusty west-northwest winds will be in place behind the front. Expect gusts primarily in the 20-30kt range much of the afternoon, tapering off some after sunset this evening.

ILX WATCHES/WARNINGS/ADVISORIES

None.