textproduct: Chicago

KEY MESSAGES

- Scattered showers/isolated thunderstorms this morning then breezy and much cooler.

- Dangerous swimming conditions at Indiana Lake Michigan beaches today and possibly again Thursday.

- Shower and thunderstorm chances return Tuesday and Wednesday. There is the possibility for another severe weather event on Wednesday along with heavy rain/flooding.

DISCUSSION

Issued at 234 AM CDT Sun Jun 14 2026

Scattered showers and thunderstorms moving across far eastern IL and northwest IN will move east of the local area in the next few hours with heavy rain the main threat with this activity. The cold front will continue to move across the rest of the area through the morning hours, shifting winds to the northwest. Models are in good agreement with at least scattered showers continuing to move across the area through mid morning and this trend looks reasonable given current activity across eastern IA and western IL. May need to have higher pops for this activity, which will end from west to east during the mid/late morning. There will remain a low chance for a few thunderstorms with this activity but not expecting the activity to be as strong as the current thunderstorms. Once the precipitation ends/shifts east of the area later this morning, dry weather is expected, however, there is a small chance for some sprinkles or a few showers this afternoon across northwest IN and did add slight chance pops for this potential.

High temps today are bit challenging given temps are currently in the upper 60s/lower 70s and its unclear how much temps may drop before clouds partially clear and some sunshine may appear this afternoon. But overall, daytime highs are expected to be mainly in the lower 70s, perhaps some mid 70s.

Northwest winds will gust as high as 30 mph through sunset and then quickly diminish. These stronger northwest winds will allow for building waves along the northwest Indiana shore of Lake Michigan resulting in dangerous swimming conditions. Current beach hazard statement remains on track.

The models continue to show an upper trough and surface cold front moving across the Great Lakes Region on Tuesday. This will bring a chance of showers and thunderstorms to the area and the new SPC Day 3 outlook has a level 1 for the potential for a few strong or severe thunderstorms. Still some uncertainty for timing and location but current trends support mainly afternoon and the eastern cwa.

Attention will then turn to Wednesday when the models are showing the potential for another severe weather event across parts of the region. While current trends show the best instability remaining southwest and south of the local area, the wind fields are quite concerning with low pressure possibly tracking across northern IL or southern WI. The weaker instability may be overcome by the stronger wind fields, similar to an early Spring-like event. In addition, the forecast precipitable water values range from 1.5 to 2 inches Wednesday. Despite possibly fast moving storms, torrential rain and flooding would also be possible.

Models then differ on how much the surface low deepens and how strong the gradient becomes Wednesday night into Thursday. If the gradient does strengthen, northwest winds may gust into the 30+ mph range and this would allow for another period of building waves and dangerous swimming conditions at Indiana Lake Michigan beaches. cms

AVIATION /18Z TAFS THROUGH 00Z TUESDAY/

Issued at 1227 PM CDT Sun Jun 14 2026

There are no significant aviation weather concerns anticipated through the period.

The rain has ended across the terminals, but a VFR deck of strato cu will persist this afternoon before scattering out towards sunset. Northwest winds will remain breezy this afternoon, with gustiness of 20-25 kt at times. A lake breeze will develop this afternoon across southeastern Cook eastward into northwesterly IN. It remains possible that as the winds ease towards sunset that this lake breeze makes a run towards ORD and MDW. Accordingly, there could be a brief period in which the winds turn north-northeasterly around sunset. Fortunately, it appears wind speeds would be light and on a diminishing trend. For this reason, we opted to leave a formal mention out of the TAF. Otherwise, expect winds to become light from the west-southwest overnight, then turn westerly around 10-15 kt during the day Monday.

KJB

LOT WATCHES/WARNINGS/ADVISORIES

IL...None. IN...Beach Hazards Statement until 10 PM CDT this evening for INZ001-INZ002.

LM...None.