textproduct: Central Illinois

KEY MESSAGES

- Thunderstorms will be most widespread the remainder of the afternoon, primarily near and south of I-72/Danville. While the overall severe weather threat is not particularly high, funnel clouds will be possible through the remainder of the afternoon in this area.

- Cooler nights are expected both tonight and Sunday night (lows in the 60s), before a return to very warm and more humid conditions for the work week. Probabilities of highs above 90 degrees are highest across the Illinois River Valley Tuesday through Saturday (40-60% chance), with chances increasing over eastern Illinois by late week.

DISCUSSION

Issued at 222 PM CDT Sat Jul 11 2026

Short Term (through Sunday):

Upper low continues to drift eastward this afternoon, with satellite and radar imagery suggesting a center west of Effingham. Storms have been developing lately along a surface boundary, which is roughly just south of I-72. Non-supercell tornado parameter from SPC mesoanalysis ranges from 2-3 around Springfield (value of 1 indicates an enhanced potential), and a couple funnels have recently been reported around Springfield. RAP guidance suggests the funnel potential will shift southward through the afternoon, and a Special Weather Statement was issued to address the situation.

The primary rain threat will be through sunset, concentrated in areas along I-72/Danville southward, as the low drifts east- southeast. While HREF continues to highlight precipitable water values approaching 2 inches, which would favor heavy rain, storms seems to be a little more progressive today, although training in a few areas. Thus, some localized totals of 1 to 3 inches are not out of the question.

Further north, drier air continues to spread southeast, with dew points in the mid-upper 60s near and north of I-74. The northeast flow will overspread much of the remainder of the forecast area the rest of the weekend, with mostly sunny conditions expected on Sunday.

Long Term (Monday through Saturday):

The overall forecast philosophy for the upcoming week has not changed. A broad upper level high pressure area will dominate the CONUS much of the week, with a rex block pattern as the upper low gradually oozes westward across the southern states. Getting late in to the week, the blocking pattern should be more aligned near the Rockies, getting more of a northwest flow into the Great Lakes. Any significant rain chances will hold off until this pattern change occurs,

Temperatures will be seasonably hot, mainly upper 80s to lower 90s for highs. NBM appears to be suppressing dew points a bit too much, given the recent wet weather and evapotranspiration. Bumping these up a bit brings heat index values to around 100 degrees Wednesday-Saturday.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1217 PM CDT Sat Jul 11 2026

Band of low ceilings near a front just south of KSPI-KCMI has shown some improvement as of late, though MVFR conditions likely to continue for another hour or so. As the front settle southward, northeast winds 8-10 knots will become prevalent, and any shower/storm activity will get pushed south as well. Will include some PROB30 mentions for thunder in this corridor through mid afternoon, then dry conditions prevail the remainder of the forecast period.

ILX WATCHES/WARNINGS/ADVISORIES

None.