textproduct: Chicago

KEY MESSAGES

- Areas of fog, some potentially dense, may develop again early Wednesday morning near Lake Michigan. - An extended period of dry and above to much above average temperatures is expected through the upcoming weekend.

DISCUSSION

Issued at 154 AM CDT Tue Oct 20 2026

No significant weather is expected through the upcoming weekend with above to much above average temperatures each day. Generally light winds should allow weak lake breezes to form each of the next several afternoons, but only result in slightly cooler conditions right near the lake. A modest increase in moisture in the wake of the afternoon lake breezes could allow for some ground fog to form during the early morning hours the next few days. Otherwise, look for mostly sunny conditions for the remainder of the work week.

- Borchardt/Izzi

AVIATION /18Z TAFS THROUGH 00Z THURSDAY/

Issued at 1255 PM CDT Tue Oct 20 2026

Key aviation forecast messages:

- IFR or lower VSBYs in BR/FG may develop again early WED AM.

The primary concern through the period is the potential for fog near Lake Michigan early Wednesday morning, some of which may become locally dense. Model guidance that performed well with this morning's dense fog depicts another round of fog development over a similar area and extends slightly farther southeast. Have accordingly included MDW with the reduced VSBYs as low as 1 SM with this update to hint at increasing confidence in fog development. If this signal persists and additional guidance begins to pick up on the potential for dense fog, LIFR (or lower) conditions may need to be introduced with later updates.

Otherwise winds will remain light (under 10 kt) initially out of the SE, turning E to ENE behind a weak lake breeze this afternoon. Winds then ease and become light and variable again overnight eventually settling into a SSW direction after daybreak Wednesday.

Petr

LOT WATCHES/WARNINGS/ADVISORIES

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