textproduct: Central Illinois

KEY MESSAGES

- A decaying line of showers will push southward through our area today. Cooler and drier weather returns tonight and persists through Saturday.

- A stretch of seasonably warm weather is expected to begin Sunday and last through next week, with daily temperatures climbing near 80 degrees. Gusty winds, occasionally reaching 30-40 mph, will accompany this warm period.

- A multi-day severe weather risk is emerging for the middle- to- late parts of next week.

DISCUSSION

(through next Friday) Issued at 526 AM CDT Fri Apr 10 2026

A weakening line of thunderstorms is currently observed on radar, aligned with a surface cold front stretching from Quincy to Kankakee. Infrared satellite imagery indicates that cloud tops are warming, and both convective activity and rainfall rates are decreasing as atmospheric instability diminishes.

Despite this weakening trend, high-resolution weather models (CAMs) consistently predict showery activity will persist as the front continues its southward movement through the afternoon. This persistence is supported by factors that maintain lift and moisture: ascent along the front itself, a low-level jet exceeding 30 kts, and energy from subtle mid-level shortwaves, all coinciding with a narrow band of sufficient RH.

In terms of rainfall accumulation, while some areas, particularly near the Illinois River Valley, could see totals between 0.25" and 0.50" through the early morning, the latest HREF guidance for the 6-hour QPF PMM is more conservative. It suggests that most areas along and south of the Interstate 72 corridor will likely receive 0.1" or less as the decaying band of showers pushes through toward midday.

A brief period of cooler and drier weather is expected from later today through Saturday. This is due to the surface front settling just south of the forecast area, followed by surface high-pressure building over the Great Lakes region.

Afternoon temperatures today will vary, with highs in the 60s near and north of the front, and lower 70s ahead of it. Then, as the front moves south tonight, overnight lows are expected to drop into the 40s, with high temperatures on Saturday only peaking in the 60s areawide.

A shift to warmer and wetter conditions is expected starting late Saturday and lasting through much of the following week. This change is due to the aforementioned front lifting back northward as a warm front, fueled by strong low-level warm air advection across the central U.S. upstream of an energetic upper-level low moving inland from the West Coast. Daily temperatures are forecast to reach near 80 degrees from Sunday through Thursday following the passage of the warm front.

Central Illinois could see scattered showers return as early as Saturday evening, with a 10-30% chance. The better chances (30-60%) are expected Sunday evening into Monday. In both cases, the primary forcing mechanisms appear to be low-level jet and isentropic ascent, along with subtle shortwave energy moving through the region within broad southwest mid-level flow. Of note for the Sunday evening activity, the return of instability could raise concerns for some elevated hailers.

Tuesday presents a favorable environment for more widespread, and potentially severe, convection. Surface temperatures near 80 F, dewpoints in the 60s, and favorable mid-level lapse rates will generate moderate instability; all amid an intensifying mid-level jet core. Despite this, the synoptic forcing appears weak, with the surface front positioned well north of our area and no strong shortwave lifting across the region. Consequently, it wouldn't be surprising if CAMs struggle to accurately depict the initiation and evolution of storms on Tuesday.

A more clearly defined shortwave is expected to move across our region sometime between Wednesday afternoon and Thursday morning. Timing differences among various model guidance introduce uncertainty regarding the severe weather potential during this period. Nevertheless, the parameter space appears similarly favorable to Tuesday, perhaps with slightly better shear.

The outlook for late next week remains uncertain, but the key concerns stem from persistent troughing over the western United States and a continuous northward flow of Gulf moisture up the Mississippi Valley. Such a pattern suggests that our area will continue to experience periods of convection. We will need to be vigilant of not only severe weather during this timeframe, but also of flooding as successive convective events compound.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 526 AM CDT Fri Apr 10 2026

Condtions will gradually deteriorate this morning as a cold front trudges southward across the regional terminals. Ceilings will likely (60% chance or greater) lower to IFR at KPIA, KBMI, and KSPI, at least for a brief time between 12z-17z. Further east at KDEC and KCMI, the probability of IFR ceilings is less likely (40% chance or less), and MVFR will be more common.

Between 18z-00z, clouds will gradually lift and break from MVFR to VFR, as the cold front departs well south of the terminals.

With frontal passage ongoing, surface winds will veer from west to north to east throughout the TAF period.

ILX WATCHES/WARNINGS/ADVISORIES

None.