textproduct: Chicago

KEY MESSAGES

- Next significant chance of rain is Sunday with potential for locally heavy rainfall.

DISCUSSION

Issued at 121 AM CDT Thu Jun 18 2026

After a couple of active days, a much quieter weather pattern expected the next few days. Northwest flow aloft will persist with high pressure across the Ohio Valley blocking any return moisture from the Gulf. A couple of subtle/weak perturbations in the northwest flow will could bring some spotty showers to the area, mainly Friday night. Coverage is expected to be on the low side, as is confidence in it raining, so the slight chance to chance pops offered up by the NBM seem reasonable. Temperatures the next couple of days will be a bit below average with comfortable dewpoints generally in the 50s.

For days now, medium range guidance has been in good agreement in bringing a stronger shortwave trough into the Midwest late in the weekend. By Saturday, the aforementioned surface ridge is expected to shift eastward allowing for southerly flow from the Gulf to advect moisture northward in advance of the next system. There remains some latitudinal variability and differences in guidance with respect to the track of the associated sfc low, but there has been a pretty consistent signal for a swath of potentially heavy rainfall setting up in or near our CWA Sunday. Accordingly, NBM pops are quite high and no changes were needed.

Northwest flow aloft will continue into next week. Drier weather is expected to start the week in the wake of the Sunday system. Next chance of showers/storms looks to be toward the middle of next week. Temperatures next week look to remain near to slightly below average.

- Izzi

AVIATION /12Z TAFS THROUGH 18Z FRIDAY/

Issued at 626 AM CDT Thu Jun 18 2026

Mvfr cigs this morning. Chance of showers this morning. Gusty northwest winds this morning.

Mvfr cigs will continue through late morning across the terminals and a few hours of low mvfr cigs are possible along with a few showers or sprinkles. Cigs will slowly lift to low vfr by early this afternoon and then scatter out this evening.

Winds are becoming northwesterly currently and will remain northwest this morning with gusts into the lower/mid 20kt range. These gusts will slowly diminish through the late morning and end this afternoon as directions turn back westerly. Speeds will diminish under 10kts with sunset this evening. cms

LOT WATCHES/WARNINGS/ADVISORIES

IL...None. IN...Beach Hazards Statement until 3 PM CDT this afternoon for INZ002.

LM...Small Craft Advisory until 9 AM CDT this morning for the IL and IN nearshore waters.