textproduct: Central Illinois

KEY MESSAGES

- A slow moving weather system passing by to our south will bring light rain and gusty winds through Wednesday.

- Dry and seasonal weather will return late this week. Temperatures turn cooler for the weekend then rebound next week.

DISCUSSION

Issued at 153 PM CDT Tue Oct 28 2025

Water vapor imagery early this afternoon shows a large trough extending southward into the central US with high pressure ridging centered near Hudson Bay. Moisture advection and large-scale ascent out ahead of the wave has resulted in a widespread blanket of low stratus and areas of light rain/drizzle. A shortwave trough embedded in the parent wave will become closed off over the central Plains this evening, with a surface low developing in northeast Texas. Rain chances increase tonight as the surface low pivots northeastward, largely passing by to the south of the forecast area. Precipitation chances continue into Wednesday, though will gradually taper off from north to south, lingering in the southeast the longest. Precipitation amounts appear relatively light for most, but deeper moisture close to the center of the low should allow more beneficial amounts to fall over southern parts of the area. The 28.12Z HREF showing the best areas for seeing over 0.50" of rain (50-70% chance).

As the low deepens tonight and the pressure gradient tightens over the region, east-northeast winds with gusts up to 30-35 mph will become common through Wednesday. The rain and wind will ease by late Wednesday afternoon/evening as the upper low occludes and merges with a separate low over the Great Lakes Region. The entire system will make it's way toward the Mid-Atlantic states by Wednesday night/Thursday.

The weather turns dry and seasonally cool by the end of the week as high pressure settles in behind the departing storm system. Flow aloft becomes a bit more progressive by the weekend as a few upper disturbances dive southward toward the area, bringing additional chances for light rain later this weekend. Mid-level heights begin to rise by the early to middle parts of next week, bringing another extended period of dry weather and warmer temperatures.

NMA

AVIATION

(For the 18z TAFs through 18z Wednesday Afternoon) Issued at 1159 AM CDT Tue Oct 28 2025

Surface observations reveal deteriorating conditions overspreading central IL from the south late Tuesday morning, as an area of low pressure deepens across the lower Mississippi River Valley. This trend is slated to continue throughout the afternoon, with occasional LIFR ceilings possible (10-20% chance) beneath the more persistent rain showers. In general, the most widespread rain coverage and worst flight conditions will be this evening, with rain tapering off from north to south towards daybreak Wednesday morning. At the same time, a tightening surface pressure gradient will result in a sharp rise in winds, which are forecast to become sustained at 15-20 kt with occasional gusts over 25 kt by the end of the forecast period.

Bumgardner

ILX WATCHES/WARNINGS/ADVISORIES

None.