textproduct: Central Illinois

KEY MESSAGES

- Two periods of severe weather are expected through tonight. Of those, the first one (2-10 pm) would be most likely to produce all severe weather hazards, primarily west of I-55. The second one, after midnight, will mainly see a localized damaging wind threat.

- A trend for cooler weather is on tap for the second half of the weekend, into Tuesday. There is concern for a hard freeze in parts of central Illinois Monday night, mainly focused on areas near and north of I-74.

DISCUSSION

Issued at 137 PM CDT Fri Apr 3 2026

Through Saturday:

A warm front was located roughly along I-72/US-36 early this afternoon, with temperatures south of it in the lower 70s and dew points in the mid 60s. Recent satellite imagery shows this particular region, while still having a fair amount of clouds, has had some breaks that have helped boost mixed layer CAPE's to around 1000 J/kg. Noontime run of the WoFS model suggests the boundary lifting about as far north as Peoria by mid afternoon. WoFS output, as well as recent runs of the HRRR and the 12z RRFS, are all focusing on convective initiation in the 2-3 pm time frame. This seems on track, as visible satellite is showing some towering cumulus centered along I-72, and some showers have been popping recently in east central Illinois. While severe weather is not a slam dunk this afternoon and evening, there are enough components that all hazards remain in play. However, most of this focus will be west of I-55, and especially toward the Illinois River valley.

The first batch of storms will likely be out of our forecast area by late evening, but the line of storms associated with the cold front won't be too far behind. Main focus for that band will be in the midnight to 5 am time frame, with the main concern being with localized 50-60 mph wind gusts. After that, rain tapers from west to east on Saturday as the front pushes into Indiana by midday.

Sunday through Tuesday:

Much of this period will be fairly tranquil, as high pressure settles into the mid Mississippi Valley. Main concern in this time frame is with the cooler temperatures, and potential for a hard freeze. Latest LREF has about a 40% chance of a hard freeze (lows 28F or colder) Monday night, roughly along and north of I-74.

Wednesday through Friday:

A significant warming trend takes place, as the upper flow becomes more zonal, and high temperatures return to the 60s and 70s. Main feature of note will be a strong shortwave tracking across the northern states Wednesday-Thursday, with a trailing cold front arriving around Thursday. As it starts to parallel the upper flow, an extended chance of rain begins to set up.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 618 PM CDT Fri Apr 3 2026

Cluster of strong/severe storms is moving NE and will be impacting KPIA before 00z, and likely stay just west of KBMI. Wind gusts near 50 knots possible with the strongest storms. Main threat for more widespread thunder activity will mainly be in the 06-10z time frame from west to east, as a cold front moves through the area.

Outside of the storms, there will be a period of IFR or low MVFR ceilings behind the front, mainly from about 10-18z. Steady improvement is expected around midday. Expect southerly winds to become west behind the front late tonight, with gusts 20-25 knots persisting through much of Saturday.

ILX WATCHES/WARNINGS/ADVISORIES

None.