textproduct: Chicago

KEY MESSAGES

- Dry weather with seasonable temperatures is expected through much of the upcoming week.

DISCUSSION

Issued at 203 AM CDT Sat Oct 3 2026

High pressure centered over northern Lake Michigan early this morning will drift eastward today. The combination of clear skies, light winds, and very dry air aloft has allowed temps to fall into the 40s for interior locations. Patchy shallow fog has also been observed and should continue through sunrise. While some of this fog could be dense, not expecting any widespread coverage.

A mid-level wave over far southern Saskatchewan will amplify while tracking ESE across the Upper Great Lakes tonight into Sunday morning. While mid and upper-level support will be fairly robust, mid-level moisture sufficient for widespread precip will remain confined to near the wave. However, a notable axis of steeper lapse rates aloft suggests that a band of isolated to widely scattered mid-level showers could brush the northern CWA during the overnight hours. Have included slight chance showers north of I-88 during this time. Otherwise, an associated cold front will cross the area with little fanfare during the predawn hours through mid-morning Sunday.

Broader WNW flow aloft will prevail across the northern CONUS through the upcoming week, with the upper-jet displaced into southern Canada. Meanwhile, persistent high pressure will cut off low-level Pacific and Gulf moisture. Cannot rule out isolated showers brushing the area to the north on Wednesday and again Thursday night with embedded waves crossing the far northern Great Lakes, but the area may very well end up precip- free through next week. Temps will be fairly seasonable next week. Monday will likely be the coldest night of the stretch with outlying areas possibly falling into the upper 30s.

Kluber

AVIATION /12Z TAFS THROUGH 18Z SUNDAY/

Issued at 604 AM CDT Sat Oct 3 2026

Southeasterly winds around 10 kts will develop after sunrise this morning. Winds will then turn out of the south and eventually south-southwest late this evening and overnight.

A robust disturbance currently shifting towards the Dakotas will move across the region tonight. At this time, it appears as if the very dry airmass in place will probably hold the most expansive precipitation coverage well to the north of the area. However, an narrow ribbon of instability will advance across the terminals late this evening and can't rule out a brief 2-3 hour window for a few sprinkles or showers. Chances currently look a bit too low to warrant PROB30 groups at this time. Winds will then turn out of the west around 10 kts on Sunday morning.

Carlaw

LOT WATCHES/WARNINGS/ADVISORIES

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