textproduct: Central Illinois

KEY MESSAGES

- The first snow flakes of the season are on tap for locations along and northeast of a Bloomington to Mattoon line late tonight into Friday morning. Accumulations will be minor and confined to grassy, elevated surfaces.

- Below normal temperatures will prevail through the weekend with temperatures gradually warming back above normal by the middle to end of next week.

DISCUSSION

Issued at 115 PM CST Thu Nov 12 2026

Upper air analysis shows a large trough of low pressure centered over the northeast US with ridging over the western half of the country. Several shortwave disturbances are rotating through the trough early this afternoon, with one of note working through central Illinois. This feature has provided enough low- level moisture and synoptic lift to result in scattered showers which are working into southeast parts of the state as of 1 pm. Drier conditions are expected through the overnight hours for most with the exception being over east-central Illinois where a lake-effect rain/snow band is forecast to stretch as far south as a roughly Bloomington to Mattoon line. Overnight lows hovering around freezing will be cold enough to allow the first snowflakes of the season to fall for some, with even some light accumulations of a tenth or two of an inch possible on grassy, elevated surfaces. Precipitation chances will linger into Friday before the fetch over the lake turns more north-northwesterly, shifting the band east of the area.

North/northwest flow aloft will remain in place over next few days, keeping temperatures cooler than normal through the beginning of next week. The upper trough will slowly shift east late this weekend with ridging filling in behind it. This will result in the rising of mid-level heights and temperatures gradually warming by the middle to late parts of next week. Surface high pressure will keep precipitation chances minimal this weekend into next week.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 521 PM CST Thu Nov 12 2026

For the most part, VFR conditions will prevail over central Illinois through Friday afternoon, with periodic ceilings near 4-5kft. Main concern will be at KCMI, where winds off Lake Michigan will bring a plume of lower ceilings and periodic rain/snow showers. NBM probabilities of ceilings below 3000 feet increase to about 50% by 06z, and largely will stay in that range into early Friday afternoon. Current indications are that lower visibilities will be more likely toward KDNV.

Northwest winds will subside a bit early this evening, though largely should stay near or above 10 knots through the forecast period.

ILX WATCHES/WARNINGS/ADVISORIES

None.