textproduct: Chicago

KEY MESSAGES

- Tonight will be the coldest night of the season so far with lows in low to mid 40s (perhaps a few spots in the upper 30s) away from the Chicago urban heat island.

- Extended period of dry weather with seasonable temperatures though much of next week.

DISCUSSION

Issued at 214 AM CDT Fri Oct 2 2026

Rain is gradually ending from northwest to southeast early this morning as the main trough responsible for our extended period of rain exits eastward. Precip is now confined to primarily east of I-57, with the remainder of the forecast area expected to be precip-free by sunrise. Clouds will clear this morning as weak ridging and plenty of dry air aloft advect in from the west, leading to generally sunny skies by the afternoon.

Surface high pressure will then drift eastward across Wisconsin and Lower Michigan this afternoon into Saturday morning. After a cool (but seasonable) day with highs in the mid 60s today, decoupling winds within a notably drier airmass will promote plenty of cooling tonight. Low temperatures in the lower to mid 40s will be common away from the core of the Chicago heat island. Would not be surprised to see some readings in the upper 30s for the typically colder spots across the northwest half of the CWA. Will also need to keep an eye out for patchy shallow fog toward sunrise around the Illinois/Kankakee River valleys northward into the south and west Chicago metro where heavier rain fell the past couple days and slightly higher lake-modified air advects inland.

With the upper-jet displaced well to the north and persistent high pressure cutting off Gulf moisture through next week, we will head into a rather quiet stretch of weather. Cannot rule out a few isolated showers with a cold front brushing the area to the north on Sunday and again on Wednesday, but the area may very well end up precip-free through much of next week. Temps will be fairly seasonable during this period. Monday will likely be the coldest night of the stretch with outlying areas possibly falling into the upper 30s.

Kluber

AVIATION /06Z TAFS THROUGH 12Z SATURDAY/

Issued at 1221 AM CDT Fri Oct 2 2026

Rain is coming to an end at the Chicago-area terminals. A brief period of MVFR cigs is possible for the next few hours before VFR conditions return. North/northwesterly winds will prevail this morning, but will likely shift just east of north through mid-late morning at the Chicago-area sites. Winds may occasionally gust to around 20 kts into the afternoon but will quickly ease during the evening to under 10 kts.

There is a small chance for some patchy shallow BR/fog into Saturday morning, although chances and coverage remain too low for a mention in the TAFs.

Carlaw

LOT WATCHES/WARNINGS/ADVISORIES

IL...None. IN...None. LM...Small Craft Advisory until 4 AM CDT Saturday for the IL and IN nearshore waters.