textproduct: Chicago

KEY MESSAGES

- Scattered showers with isolated thunderstorms today.

- Chance of showers Saturday night/Sunday morning.

- Active pattern mid/late week with showers and possible thunderstorms, then turning colder into next weekend.

DISCUSSION

Issued at 208 AM CDT Fri Oct 9 2026

An area of showers and thunderstorms extends across parts of IA early this morning. This activity will continue moving east/ southeast through mid morning, though a gradual weakening trend is expected, especially on the eastern/leading edge with quite a bit of uncertainty for how much of this precipitation will reach the southwest cwa this morning. Have capped pops at likely and even this may be too high. Eventually, as the main wave moves across northern IL this afternoon, additional showers and a few thunderstorms will be possible from midday through late afternoon with precipitation chances ending by sunset as any lingering activity shifts east over Lake Michigan.

High temperatures today will be tricky with extensive high/mid level cloud cover expected. Its possible high temps may be warmer than the expected lower 70s across the northern cwa but maintained those temps for now, with highs in the mid/upper 70s south of I-80.

Highs on Saturday will likely reach the upper 70s/lower 80s for most areas, but cooler along the IL Lake Michigan shore with south/southeast winds. The winds on Saturday may gust into the 25-30 mph range during the afternoon.

Increasing clouds are expected Saturday afternoon into Saturday evening as the remnants of Isaias lift north into the Ohio Valley. There will likely be a sharp cutoff to the precipitation on the northwest side of this system so the challenge will be how far northwest does the system move. Still quite a bit of uncertainty though the trend seems to support the bulk of the precipitation remaining generally east of I-57 (or further east). Did not make any changes to the blended pops which maintain a dry forecast for all but the far southeast cwa. Winds are expected to have an easterly component Sunday morning and perhaps all day Sunday, keeping temperatures cooler near Lake Michigan but with some sunshine possible midday in the afternoon, highs could easily reach the mid/upper 70s inland.

Another warm day is expected Monday with high temperatures in the lower to mid 80s expected. Its possible a few locations may tag upper 80s Monday afternoon. A cold front is then expected to move across the area Tuesday morning, though there remains uncertainty on timing. A slower arrival will likely allow for a very mild Monday night with lows possibly only in the 60s and then highs rebounding into the upper 70s/lower 80s on Tuesday, south of the frontal boundary. There will also be a chance of showers and possibly a few thunderstorms during this time period though quite a bit of uncertainty for coverage.

The cold front is then expected to stall as low pressure develops over the Plains and lifts back north as a warm front Thursday/Thursday evening, as the low deepens and races northeast to the northern Great Lakes by Friday morning. Shower and thunderstorms chances will be possible as the warm front lifts north across the area and then again as a strong cold front moves across the area Thursday night or Friday morning. While its just beyond the end of the 7 day period, it appears there could be much colder temperatures for at least a few days behind this cold front and going into next weekend. cms

AVIATION /12Z TAFS THROUGH 18Z SATURDAY/

Issued at 614 AM CDT Fri Oct 9 2026

Forecast concerns for the terminals...

- Period of scattered showers this afternoon, 15-20% chance for an isolated lightning strike.

A stout mid-level disturbance continues to drift east across IA towards northern IL this morning. Associated with this disturbance is an area of showers and thunderstorms that is currently weakening, but should still have some scattered showers with it as it moves through northern IL and portions of northwest IN this afternoon. That said, forecast soundings continue to show decently steep lapse rates aloft which may be able to develop an isolated lightning strike or two this afternoon. So while the overall threat for lightning at the terminals is low (15-20% chance) have opted to maintain PROB30s for now. Regardless, any showers/storms this afternoon should only last about 2-3 hours at any one location.

Otherwise, expect mostly cloudy VFR ceilings (bases around 8000-10000 ft) to prevail through this afternoon before skies scatter out overnight. Winds today will continue to settle into a southeast direction this morning before turning more east- southeast this afternoon with speeds around 5-10 kts. Directions will then turn back southeasterly overnight and then south-southeast by Saturday morning. Speeds will begin to increase late Saturday morning with gusts around 20-25 kts expected for Saturday afternoon.

Yack

LOT WATCHES/WARNINGS/ADVISORIES

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