textproduct: Central Illinois

KEY MESSAGES

- Wind gusts of 30-40 mph are likely tonight through Friday afternoon. The strongest winds will be west of I-57.

- Much cooler weather will settle into the region through the weekend potentially resulting in areas of frost both Saturday and Sunday mornings. There is a 40-60% chance of temperatures dropping below 32 degrees north of the IL River Valley.

DISCUSSION

Issued at 129 PM CDT Thu Oct 15 2026

The warm front pushed back north this morning bringing a round of rain across central IL. PWATs are expected to be around 1.8-2.1 inches this afternoon, which is very high for the month of October. The 12z upper air sounding showed 1.77 inches for PWAT. The average PWAT for October 15th is around 0.6-0.7 inches based off the SPC sounding climatology. The good news is that our soils can handle this rain since we have been so dry lately. The rain is welcomed. The LPMM is showing some localized swaths of 1-3 inches of rain through tonight near the I-70 corridor on top of what has already fallen this morning. The rest of Central IL could see 0.25-0.75" of rain during this time. Some areas under the heaviest rain has already achieved the 1-3" amounts.

When the cold front advances east this afternoon/evening, a severe weather risk and additional rain will be accompanying it. With the 1630z update, SPC has introduced a slight risk (level 2 of 5) to I- 70 and south and a marginal risk still from about a Pittsfield to Gibson City line and south. The environment looks supportive of strong to severe thunderstorms if we can recover fully from the morning stratus/fog and morning rainfall. Storm type looks like it may begin as discrete, supercells that will evolve into a multicell/QLCS mode as it exits to the east. Damaging winds and a tornado or two are the main hazards. Storms will move through from ~20z-02z. After these storms exit to the east, additional light showers could occur through Friday afternoon. After Friday afternoon, the forecast is expected to be dry through the extended period.

The cold front pushes off to our east early tomorrow morning. The pressure gradient with the passing low pressure system will tighten behind the cold front. Wind gusts around 30 mph will start late this evening and will continue for most of the day tomorrow. Wind gusts tomorrow will be around 30-40 mph, with the strongest winds possible west of I-57. The HREF shows a 40-60% chance of gusts greater than 35 mph west of I-57 in the morning. Winds should relax to closer to 15-20 mph by sunset tomorrow.

Cooler, more fall like temperatures will be ushered in behind the front for a few days. Highs tomorrow and Saturday will be in the 50s, with lows in the mid to upper 30s. There is a chance for some patchy frost to develop in western IL Saturday morning, depending if the wind will drop to near calm. Saturday morning may also have a risk for a light freeze in some locations north of the IL River Valley, especially in low spots. The HREF is showing a 40-60% chance of temperatures dropping below 32 degrees north of the IL River Valley. Patchy frost is possible again Sunday morning. Beyond Sunday morning, temperatures will begin to warm back up to low 70s for highs on Monday, then to upper 70s by Wednesday next week.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 642 PM CDT Thu Oct 15 2026

A cold front was pushing through central IL early this evening. This will veer winds from WSW to WNW, with 20-25 kt gusts becoming common later this evening and persisting through Friday. A mix of ceilings currently range from IFR at KPIA-KBMI to VFR farther south. The trend will be toward MVFR ceilings areawide overnight and through much of Friday. A break for VFR ceilings appears likely at most sites from around 09-14z, before wrap around moisture moves back in. Isolated instability -SHRA will be possible on Friday, however with low coverage kept mention to VCSH.

ILX WATCHES/WARNINGS/ADVISORIES

None.