textproduct: Central Illinois

KEY MESSAGES

- Localized flash flooding is the primary concern through Saturday morning, particularly along the I-74 corridor due to repeated rounds of heavy rain. Expect rainfall totals of 1.5 to 3.0 inches in these persistent bands, with significantly lower amounts elsewhere.

- A low-probability, conditional threat for a stray damaging wind gust or brief tornado exists tonight, primarily across west-central and southwest Illinois. While most storm activity will remain sub-severe, remain alert for updates.

- Pleasant, dry, and warm weather follows for Monday and Tuesday, before rain chances return mid-to-late next week. Confidence in the late-week timing remains low, so please check back for later forecasts.

LONG TERM

(Sunday Night through Friday)

Upper-level height rises and an amplifying western ridge will build into the Great Lakes region early next week, marking a swift transition back to seasonably warm, dry, and pleasant summer weather for Monday and Tuesday. High temperatures will comfortably rebound into the mid-80s beneath mostly sunny skies.

The next opportunity for organized precipitation arrives mid- week as a robust northern-stream shortwave drives a cold front toward the Upper Midwest. Guidance exhibits considerable spread regarding how far south this boundary can penetrate into central Illinois as its parent upper-level dynamics rapidly displace eastward into Canada. Will maintain conservative 20-30% PoPs for Wednesday through Thursday to account for these timing and boundary-position uncertainties.

However, recent deterministic and ensemble guidance hints at a secondary reinforcing shortwave digging across the Plains and riding along the quasistationary surface boundary Thursday. This would increase local baroclinicity and reinvigorate the cold front, driving it southward across the local forecast area. This latter scenario would favor higher probabilities for showers and thunderstorms during the Thursday into Friday timeframe and will bear watching in future guidance updates.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 645 PM CDT Fri Jul 31 2026

Unfavorable flying conditions are expected the next 24 hours as a surface low works through the region, bringing periods of showers and storms, low ceilings, and reduced visibility. A cold front approaching from the west will bring our first wave of precipitation late this evening. The center of the low moves into west-central IL shortly after midnight, bringing a brief break in shower/storm activity. However, widespread IFR to occasionally LIFR ceilings will become likely during this time. Higher chances for precipitation return late Saturday morning/early afternoon and linger through Saturday evening.

Breezy southeast winds will turn light and variable as the low moves through the region overnight, then pick up again out of the north- northeast later on Saturday.

ILX WATCHES/WARNINGS/ADVISORIES

None.