textproduct: Chicago

KEY MESSAGES

- Another period of rain expected (>80% chance) across the area late Monday into early Tuesday.

- A modest warming trend is expected into early next week before temperatures turn much colder for Thanksgiving.

DISCUSSION

Issued at 303 AM CST Sat Nov 22 2025

Primarily dry and seasonably mild weather (with more sunshine) is expected for the weekend, owing to an area of surface high pressure shifting across the mid-section of the country. As this surface ridge axis passes southward across the area this morning, surface winds will turn southwesterly. The associated influx of a warmer airmass will thus support warmer temperatures today, with afternoon readings topping out in the low 50s for most locations under partly cloudy skies. A weak cold front will shift across the area into early this evening, but only a brief increase in mid-level cloud cover and a westerly wind shift is anticipated in our area as result of its passage. With no push of cold air expected with this front, we will be set to have another nice late November day for Sunday. Mainly sunny skies through the day should support highs in the low to mid 50s.

Conditions will remain seasonably mild Monday and Tuesday, but a period of widespread light soaking rainfall is expected late Monday into Tuesday morning (highest chances of 80%+ Monday evening and night). Forecast confidence remains high with this period of rain, owing to continued very good model and ensemble agreement with the east-northeastward ejection of the upper low currently located just off the Baja California coast. This feature is slated to move out across the Mid-Mississpi Valley region into the Lower Great Lakes into Tuesday morning.

Following quickly on the heels of this system, another quick moving northern stream impulse is expected to dig in across the western Great Lakes by midweek. As it does, surface low pressure will deepen and consolidate to our north across the Upper Great Lakes, with an associated strong east-southeastward surging cold front likely to move across our area sometime Tuesday night. While this does not look to be a good precipitation maker for our area on Wednesday (though flurries or intermittent light snow showers may occur), strong cold air advection is expected on gusty northwesterly winds (possibly gusting in excess of 40 mph for a period). This will set the stage for a turn towards much colder weather for the second half of the week, including on Thanksgiving Day. High temperatures are current forecast to only be in the low to middle 30s with wind chills in the teens and 20s.

Beyond Thanksgiving, signs continue to point to a turn towards a much more active weather pattern across the central CONUS going into the first part of December. Ensemble guidance during this period continues to favor building heights (increased ridging) across the north Pacific into Alaska (negative Eastern Pacific Oscillation). Teleconnections related to this pattern should in turn favor a shift towards an increasingly amplified downstream upper-level pattern across North America, with deep troughing over the western CONUS and enhanced ridging in the eastern and southeastern CONUS. Forecast specifics this far out for a certain area remain largely unclear. However, it is certainly a noteworthy larger scale pattern shift that will need to be monitored for potentially impactful weather systems affecting the central CONUS during the latter part of the holiday weekend into next week.

KJB

AVIATION /18Z TAFS THROUGH 00Z MONDAY/

Issued at 1040 AM CST Sat Nov 22 2025

Expect VFR conditions through the period. A mid-level stratus deck will cross the terminals this afternoon through early evening. Cannot fully rule out a few sprinkles at RFD, but any precip is expected to remain north of the area well into Wisconsin. Otherwise, SSW/SW winds around 10 to 15 knots will veer WNW 5 to 10 knots overnight through Sunday.

Kluber

LOT WATCHES/WARNINGS/ADVISORIES

IL...None. IN...None. LM...Small Craft Advisory from 9 PM this evening to 10 AM CST Sunday for Gary to Burns Harbor IN-Burns Harbor to Michigan City IN.