textproduct: Central Illinois

KEY MESSAGES

- Near to slightly above average temperatures along with dry conditions will dominate central Illinois through the rest of the weekend and into early next week.

DISCUSSION

Issued at 135 PM CDT Sat Oct 3 2026

The latest surface analysis has a high over Michigan and frontal boundary stationary extending southwest from the mid Atlantic through the Southeast to Texas. An upper level wave will pass through the Dakotas today and through MN/WI/MI tonight. The southern extent of precipitation with this trough will be as far south as perhaps the IL/WI border overnight tonight. There will be a cold front associated with this upper feature, but lagging behind a bit. This will allow highs to rise a bit more on Sunday (70s) than today (70-75) in most areas, except perhaps the northwest. Expect highs to be a bit cooler on Monday, back to around 70 or low 70s. The coolest night of the week will be Monday night as cool high pressure will dominate...allowing lows to dip into the lower 40s across east- central IL. A few upper 30s readings wouldn't be out of the question either.

With the jet stream to the north extending from the southern prairie provinces through the Great Lakes, weather system tracks will remain to the north of IL through much of the week. The next system to potentially affect the area looks to be on Thursday night. But then, it's a weak wave and could perhaps bring some showers to northern IL. Right now, the chance this wave affects central Illinois is under 10%, so it won't be included in the PoPs forecast right now.

Temperatures look to warm above average for the latter part of the week with the jet stream staying north. Currently expecting highs around 80 for Wed-Fri, with perhaps mid 80s by Saturday. The biggest question in the forecast is at day 7-8 when models diverge a bit. There is the potential for an upper trough to deepen over the western US while a weak TX upper low ejects northeastward ahead of the trough. This is the next big chance for rain over IL...Sunday night into Monday. While a pattern shift is possible late in the forecast period, it may hold off to the following week.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1226 PM CDT Sat Oct 3 2026

VFR conditions with relatively light winds will dominate the weather over the next 24 hrs. However, we may see gusts in some locations up to 20 kts from the ESE today through about 22Z. A low probability (10%) of vis less than 5 mi exists late tonight (09Z-15Z) near CMI and DEC. Will continue to monitor forecast trends and update if needed. Dry air in the low levels should limit mist/fog development to being rather shallow and limited in areal coverage if any does form.

ILX WATCHES/WARNINGS/ADVISORIES

None.