textproduct: Chicago

KEY MESSAGES

- Scattered showers and thunderstorms through this evening ahead of a strong cold front with falling temps behind the front.

- Possible very windy Thursday with southerly winds gusting 40-45 mph.

- Possible strong to severe thunderstorms ahead of a cold front Thursday afternoon/evening.

- An active pattern will continue through Saturday with periods of showers and thunderstorms.

DISCUSSION

Issued at 206 PM CDT Tue Mar 31 2026

The cold front has moved into far northern IL and will continue moving south across the area through this evening. Winds will shift northerly behind the front, more northeasterly near Lake Michigan, with temperatures falling into the 40s, and likely into the 30s near Lake Michigan.

Showers and scattered thunderstorms are expected to increase in coverage as the cold front moves across the area. There remains quite a bit of uncertainty for the potential for additional severe thunderstorms and the most favored area appears to be along and south of I-80 through early/mid evening. While a line of showers and thunderstorms behind the front across southern WI is expected to move across the area, this activity is not expected to be severe. Latest model trends would suggest that the precipitation well end completely for areas north of I-80 tonight with perhaps scattered activity continuing overnight across the southern half or third of the area. This precipitation may continue into Wednesday morning, again for areas south of I-80 but overall, the northern half or so of the area is looking dry through midday Wednesday with precipitation chances increasing Wednesday afternoon into Wednesday night as the cold front lifts back north as a warm front. Confidence remains low for timing and coverage of activity Wednesday night into Thursday morning. Blended pops are generally in the 70-100% range and while this is plausible, the timing/duration will likely be considerably shorter and later forecasts will be able to narrow down these chances

Precipitation should end sometime Thursday morning as the warm front lifts north of the area. Strong southerly winds are expected to develop with gusts into the 40-45 mph range possible, which would be approaching wind advisory criteria if these winds do materialize. High temperatures are likely to warm well into the 70s on Thursday.

A cold front will move through the area late Thursday afternoon into Thursday evening with showers and thunderstorms expected along/ahead of this front. Day 3 outlook has level 2 for severe storms across the southeast two thirds of the area and this looks on track. Thursday night into Friday appears to be a short break in the precipitation with another period of showers and thunderstorms Friday night into Saturday ahead of another strong cold front that is expected to move across the area Saturday. Colder air will spread across the area for Sunday/Monday and the models are now showing another clipper like system and possible precipitation Monday night. cms

AVIATION /00Z TAFS THROUGH 06Z THURSDAY/

Issued at 637 PM CDT Tue Mar 31 2026

Aviation forecast concerns for the 00Z TAFs:

- Few lingering SHRA early this evening, though TSRA threat looks to remain east/south of the terminals beyond 00Z.

- Prevailing MVFR ceilings expected for much of the period with breezy NNE winds occasionally gusting 20-25 kts. Exception will be RFD which will enjoy a period of VFR conditions this evening and again Wednesday.

- Can't rule out some spotty non-impactful SHRA at times Wednesday, though greatest potential for RA/SHRA at terminals looks to be in the afternoon and especially Wednesday evening.

Surface cold front has pushed south of the terminals as of early evening, with winds having shifted to the north-northeast. Winds will remain from the northeast through the remainder of the period, remaining breezy with gusts 20-25 kts at times. Low- level cooler air off of Lake Michigan will also support a prolonged period of MVFR ceilings (possibly some brief IFR this evening) for the Chicago terminals. RFD, further from the lake, will see periods of VFR this evening and again on Wednesday.

A few spotty showers remain along a line from roughly KVYS-KMDW at issuance time, though these should be moving east/south of the terminals shortly. Even a brief TS at MDW recently, though any further TS expected to remain east/south of the terminals and should not continue to be a factor in the immediate vicinity of the terminals. Can't rule out a few spotty showers during the day Wednesday across the terminals, but greatest chances appear to be during the afternoon and especially Wednesday evening, as a warm front lifts toward the area.

Ratzer

LOT WATCHES/WARNINGS/ADVISORIES

IL...None. IN...None. LM...Small Craft Advisory until 7 PM CDT Wednesday for the IL and IN nearshore waters.