textproduct: Central Illinois

KEY MESSAGES

- Relief from the very hot air with more seasonable temperatures arrives today. Highs will widely be in the upper 70s to low 80s with lows in the low 60s today.

- More showers and thunderstorms are likely (70-90% chance) Saturday, with a level 2 of 5 (slight) risk for severe weather and excessive rainfall, with an enhanced risk (level 3 of 5)of severe weather as far east as the STL metro, touching Scott County.

DISCUSSION

Issued at 309 AM CDT Fri Jun 12 2026

Well a peaceful day of weather is in store for today. Much less humid air has arrived as the overnight cold front pushed out the very moist airmass. We get relief from the very hot air with more seasonable temperatures starting today. Highs will widely be in the upper 70s to low 80s with lows in the low 60s.

The break from active weather will be short lived, as severe weather returns Saturday as a reinforcing cold front is expected to push through central and southeastern IL Saturday. The SPC has all of central IL in a slight risk (level 2 of 5) with the enhanced risk (level 3 of 5) as far east as the STL metro, touching Scott County. There could be some morning convection from a possible remnant MCV resulting from a decaying MCS traveling across MO overnight. Confidence in this convection is quite low, as it is hard to pinpoint a mesoscale feature like this over 24 hours out. The main hazard of concern is the damaging wind risk as a bowing QLCS is expected in the afternoon into the evening. DCAPE is around 800-1000 J/kg. Large hail and QLCS tornadoes are also possible. Forecast lapse rates look to be pretty steep (7-8 C/km). Bulk Shear of 40-50 knots. There could also be a concern for localized flooding as the line of storms move through, especially where the heaviest rain has already fallen over the last week. Some forecast sounding has a long, skinny CAPE profile to them with PWATS of 1.6-1.8 inches.

Beyond Saturday, a high pressure center sets up over the region, giving us a much needed break from the hot and active weather. Sunday and Monday will have below normal temperatures with highs in the 70s and lows in the 50s. Temperatures then warm back to near normal, with highs into the 80s by midweek into the end of the week. Rain and thunderstorms will return to the forecast Tuesday into the end of the week.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 600 AM CDT Fri Jun 12 2026

VFR conditions are expected through the 12z TAF period. Light, westerly winds will become calm and variable as the sunsets into the overnight. Clear skies are expected, but some afternoon cumulus may develop. Confidence is low of if it will develop and if it does, when and where, so it was left out.

ILX WATCHES/WARNINGS/ADVISORIES

None.