textproduct: Central Illinois

KEY MESSAGES

- Chilly conditions will prevail tonight: however, the risk for a hard freeze has decreased substantially due to expected cloud cover. Low temperatures will be coldest along the I-74 corridor where readings will bottom out around 30 degrees.

- An upper disturbance will produce a band of light rain and snow along and south of a Macomb...to Decatur...to Mattoon line late tonight into early Tuesday morning. Less than 1 inch of snow is expected on grassy surfaces.

- Warmer/wetter conditions will return by the end of the week: however, severe weather is not anticipated.

..Warmer/Wetter by the End of the Week

The current northwesterly flow pattern will be replaced by a flat west-to-east zonal flow by the middle and end of the week. This will allow temperatures to climb back above normal and also introduce increased rain chances as a series of disturbances track across the CONUS. The primary challenge with this type of scenario is trying to predict exactly where the main baroclinic zone will lay out. As the first short-wave approaches, it will drag a cold front toward central Illinois on Thursday...with the boundary then going parallel to the upper flow and becoming quasi-stationary after that. Models are showing a good deal of spread concerning placement of the boundary Friday through Sunday, so current NBM features daily rain chances through the period. It will most definitely not rain that entire time, and PoPs will be adjusted accordingly as details become clearer.

After a chilly day with highs only in the 40s on Tuesday, readings will climb back into the upper 60s/lower 70s Wednesday through Friday...then will soar well into the 70s to near 80 degrees by Sunday as the flow becomes more southwesterly. Tuesday/Wednesday will be dry days...with rain chances north of I-72 on Thursday, then everywhere Friday through Sunday. While showers and thunderstorms are in the forecast, the risk for widespread severe weather will remain low due to marginal instability and the lack of a strong upper forcing mechanism.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1201 AM CDT Mon Apr 6 2026

VFR conditions are expected the upcoming 24 hours, however a corridor of snow will be spreading southeastward toward KSPI late in the period, and could affect KSPI and KDEC by 12Z Tuesday. Ahead of this snow, increasing mid-level clouds will develop across the region. Until then, a dry cold front overnight tonight will bring a wind shift and scattered mid- level clouds. Winds SW 5-10 kts, shifting to NW 10-12 kts by 09Z-12Z and increasing to 10-15 kts with gusts up to around 25 kts by 14Z. Winds decreasing to 8-12 kts by 00Z.

ILX WATCHES/WARNINGS/ADVISORIES

Freeze Watch from late tonight through Tuesday morning for ILZ029-031-036>038-041>046.