Marine Weather and Tide Forecast for Chillicothe, IL

DISCUSSION
Issued at 244 PM CST Tue Dec 9 2025

Temperatures have warmed above freezing this afternoon throughout central Illinois, with wet bulb temperatures anticipated to support rain at the surface when precipitation begins this evening in association with a low moving southeast across Minnesota and into southern Wisconsin. The greatest coverage of rain should be just ahead of the low pressure trough as it moves across the area late tonight. Of greater impact will be the west/northwest winds behind the surface trough, continuing as a cold front moves through Wednesday morning. Wind speeds at the top of the mixed layer are around 50 knots, and we anticipate that any convective elements which may develop ahead of the cold front may enhance wind gust speeds. We've issued a Wind Advisory for much of the forecast area from midnight to noon. Snow showers potentially developing near the cold front Wednesday morning could be responsible for rapid drops in visibility when combined with the strong winds. With not much accumulation anticipated, the sudden visibility changes will likely be the primary impact from any snow.

Attention then turns to our next clipper system due to arrive in the Thursday night/Friday morning time frame. With a cold thermodynamic profile and lift peaking in the dendritic growth zone, this could be an efficient snowfall producer despite its quick movement. Snowfall may be maximized just north of the low where the greatest precip residence time is. Amounts observed with a fast-moving high SLR event like this will probably be highly sensitive to the track of the low, with 90th percentile amounts along the northern edge of the forecast area being around 4 inches.

Cold air returns in earnest this weekend, with a ~1040 mb high moving out of south-central Canada into the Midwest. Though wind speeds at the leading edge of this high are not forecast to be extreme, it doesn't take much wind to bring wind chills down substantially. The coldest wind chills are anticipated on Sunday morning, with most likely values ranging from 10 to 20 degrees below zero. In addition, some light snow is anticipated along the baroclinic zone at the leading edge of the high Saturday, with a 30-50% chance of greater than 1 inch of snow north of I-72/Danville.

AAT

AVIATION
(For the 00z TAFs through 00z Wednesday Evening)
Issued at 510 PM CST Tue Dec 9 2025

A complex TAF period is set to unfold over the next 24 hours, with LLWS and a period of showers this evening/tonight, strong wind gusts, a potential for snow squalls Wed AM, and lowering ceilings.
MVFR ceilings are likely to push in from the north around 10z, and ceilings then stay down for the remainder of the period. Some IFR ceilings can't be ruled out, especially beneath snow showers.
Winds will be southerly this evening, turning westerly overnight, then northwesterly into the day on Wednesday. 2kft winds will generally match the direction of the sfc winds, but with speeds approaching 50-55 kts at times overnight. The strongest sfc gusts are expected to occur Wed morning, when gusts as high as 50 kts are possible. Any snow that occurs will result in sharp visibility reductions, but the scattered nature of the snow showers make it difficult to pinpoint when or if it will impact any terminals directly.

Erwin

ILX WATCHES/WARNINGS/ADVISORIES
Wind Advisory from midnight tonight to noon CST Wednesday for ILZ027>031-036>038-040>045-047>056-061-062-066.