textproduct: Chicago

KEY MESSAGES

- Near record high temps possible and gusty southwest winds Monday.

- Active pattern next week with a series of precipitation chances, and then turning colder into next weekend.

DISCUSSION

Issued at 200 AM CDT Sun Oct 11 2026

A weak ridge of high pressure will slowly drift east of the area this afternoon into this evening. This will allow for light winds this morning to slowly become south/southwest through the day. High/mid clouds early will depart this morning leaving mostly sunny skies with highs ranging from the mid 70s east to the lower 80s west. Onshore winds will also keep areas near Lake Michigan cooler, mainly in the lower 70s.

An upper ridge will build across the area tonight into Monday allowing for high temps to reach the mid 80s areawide Monday with some areas likely reaching the upper 80s. Southwest winds may also gust into the 20-30 mph range Monday afternoon. Still some uncertainty on the extent of cloud cover which may be a limiting factor for temps/winds based on how much mixing occurs. Strong low level winds Monday night should keep low temps rather mild, perhaps in the upper 50s/lower 60s for much of the area. Consensus among the models now suggests winds will turn westerly Tuesday morning as a trough of low pressure passes across the area, but the expected main cold front with northerly winds may be delayed until Tuesday afternoon/evening. This would allow for another potentially very warm day Tuesday with the blended temps ranging from the upper 70s north to the mid 80s south of I-80 and these are certainly possible, so made no changes from this distance.

As for precip chances, there is a small chance for some warm air advection showers Monday morning that appear they will remain north of the area. Then as the above mentioned trough moves across the area Tuesday morning, there could be some showers and possibly a few thunderstorms, but coverage looks rather low and expecting much of the area to remain dry.

A better chance for showers and thunderstorms, for at least part of the area will arrive Tuesday night into Wednesday morning as the cold front is pushing south into central IL and central IN. Current trends suggest the best chances for rain will be south of I-80, though still uncertainty for the northern extent with this precip potential. High pressure will quickly move across the northern Great Lakes Wednesday night, which should push the front and precip chances far enough south for a break in the precip until the front lifts back north Thursday ahead of a stronger cold front that arrives Thursday night or Friday morning. Despite very good ensemble support for at least a few days of much colder temperatures across the region, the ECMWF is warmer and adds uncertainty to the overall temp expectations. Blended guidance now has low temps in the mid/upper 30s for next Sunday morning and these seem reasonable given the ensembles. Though if the cold air does materialize across the region, temps could be even colder. cms

AVIATION /12Z TAFS THROUGH 18Z MONDAY/

Issued at 609 AM CDT Sun Oct 11 2026

Forecast concerns for the terminals...

- Potential for low-level wind shear tonight, especially near RFD.

- Breezy southwest winds gusting 20-25 kts on Monday.

Mid-level ridging (high pressure) will continue to reside across the region through the TAF period which will keep generally quiet weather around. Southeast winds this morning will gradually become more south-southwesterly by midday with speeds remaining around 5-7 kts. The exception will be at GYY and MDW where a weak lake breeze will keep winds more easterly before directions become southwest after sunset this evening. Otherwise, expect the current VFR cirrus to exit the area later this morning leaving us with mostly clear skies through the period.

There is a potential for some low-level wind shear to develop after midnight tonight as a 30-35 kt low-level jet pivots into the area. Given that surface winds will slowly be increasing overnight it seems the LLWS threat is very marginal and thus have left out of the TAFs for now. But will continue to monitor forecast trends. Regardless, breezy southwest winds will develop on Monday with gusts peaking into the 20-25 kt for Monday afternoon.

Yack

LOT WATCHES/WARNINGS/ADVISORIES

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