textproduct: Chicago

KEY MESSAGES

- Below average temperatures expected through the weekend before temperatures turn more seasonable early next week.

DISCUSSION

Issued at 124 PM CDT Wed Sep 23 2026

An upper low continues to spiral over the Ohio River Valley which has maintained a large cloud shield across much of the region. In addition to the clouds, there have been some isolated pockets of drizzle and light showers in OH and IN. While a stray sprinkle cannot be fully ruled out in our northwest IN or far eastern IL counties this afternoon (~10% chance), the drier low-levels locally should keep most areas dry. Otherwise, expect mostly cloudy skies to prevail through tonight with east- northeast winds occasionally gusting to around 20 mph this afternoon. However, the continued cloud cover will only allow temperatures to peak in the mid-60s this afternoon before cooling into the low to mid-50s overnight.

A ridge of high pressure will slide east out of the central Plains tonight and push the aforementioned upper into the mid- Atlantic. This ridge is then forecast to persist across the western Great Lakes and Midwest regions through the early part of next week. Therefore, expect dry conditions during this period with gradually decreasing cloud cover (especially in our eastern CWA). Temperatures will remain on the cooler side of average with daily highs in the mid to upper 60s and overnight lows in the 50s due to persistent east-northeast winds and lingering cloud cover. That said, there remains a signal for a shortwave disturbance to drift into the ridge on Saturday. While guidance continues to hint at some showers developing with this wave, the drier mid-levels forecast across northern IL and northwest IN should keep these showers near and west of the Mississippi River. Our official forecast will have some 15- 20% POPs near and west of I-39 late Saturday afternoon and evening, but this is mainly due to the NBM being overdone with moisture. Suspect these POPs will be able to be removed in future forecast updates so plan on a dry forecast to prevail through the weekend.

The next notable chance for rain is not forecast to occur sometime near the middle of next week when a cold front pushes through the region. Prior to the front's arrival, temperatures look to rebound towards more seasonable values with highs in the 70s.

Yack

AVIATION /06Z TAFS THROUGH 12Z FRIDAY/

Issued at 1232 AM CDT Thu Sep 24 2026

There are no forecast concerns this period. Generally vfr cigs 3-5kft will continue through this evening when they are expected to scatter out with mid level clouds for early Friday morning. Some mvfr cigs are possible early this morning, mainly south of the terminals.

Easterly winds around 10kt for the Chicago terminals will continue into this evening. Elsewhere, speeds will be under 10kts early this morning then increase toward 10kt later this morning. Winds will become east/southeast under 10kts areawide this evening. cms

LOT WATCHES/WARNINGS/ADVISORIES

IL...Beach Hazards Statement until noon CDT today for ILZ006.

IN...None. LM...None.