textproduct: Central Illinois

KEY MESSAGES

- Rain chances will be most focused from Thursday night into Saturday, with potential for a number of storms tracking along a slow-moving front. There is a 30-40% chance of receiving at least 2 inches of rain in areas near/south of I-70 during this period, with an attendant concern for flooding.

- Severe weather potential is more uncertain, but a level 1 risk is in place for Thursday afternoon and night over all of the area. Damaging winds would be the main concern.

- A trend toward warmer and more humid conditions is expected early next week.

DISCUSSION

Issued at 157 PM CDT Tue Jul 7 2026

Latest water vapor imagery shows an upper low spinning across northeast Arkansas, which has triggered a few stray showers across the southeast CWA early this afternoon. Little movement in this feature is expected through mid week, until a shortwave begins to dig across the central Plains and moves into the Mississippi Valley toward Thursday. Local weather in the short term shouldn't change too much, with Wednesday's high temperatures similar to today (mid 80s) and a few showers again south of I-70.

As we get into Thursday, a cold front will settle southward as the shortwave approaches. Chances of showers/storms increase by afternoon, and will be highest from Thursday night into Friday afternoon (60-80%). A number of ensemble outputs suggest it may take until Saturday to fully get the front out of the area, as it becomes more stationary near the Ohio Valley. As such, areas near/south of I-70 will see the high PoP's lingering through the start of the weekend. With the front generally parallel to the upper flow, waves of storms with heavy rain will be a concern, and a level 2 risk of excessive rainfall is in place for Friday/Friday night in that area. Severe-wise, both the NAM and GFS show low level winds ramping up Thursday evening across especially the southern half of the forecast area (>40 knots), suggesting an increasing MCS threat. Morning SPC Day3 outlook introduced a level 1 risk over most of the forecast area, but suggested a potential increase in risk as the details become more clear.

The upper air pattern continues to show an evolution toward a strong high developing over the central Rockies and western High Plains during the weekend, then spreading across the central CONUS early next week. 500 mb heights near 600 dm are progged by the GFS and European models, which would be a couple standardized deviations above normal, and as we get closer to mid week, ridging would amplify just east of the Rockies. Core of the warmest weather in this pattern would stay more to our west, though seasonably warm and humid conditions are expected over our area through next week.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 556 PM CDT Tue Jul 7 2026

Light to calm winds and low dewpoint depressions will lead to patchy MVFR fog late tonight. Otherwise, VFR conditions will dominate through Wednesday afternoon.

ILX WATCHES/WARNINGS/ADVISORIES

None.