textproduct: Chicago

KEY MESSAGES

- Isolated to widely scattered thunderstorms possible later this evening, though the threat of severe weather has decreased.

- Dangerous swimming conditions at NW Indiana Lake Michigan beaches Sunday.

- Cooler temperatures early next week.

- Shower and thunderstorm chances return Tuesday and Wednesday. The possibility exists for another severe weather event on Wednesday.

UPDATE

Issued at 837 PM CDT Sat Jun 13 2026

Convection had struggled earlier this afternoon, remaining limited in coverage. This was likely due to a lack of low-level convergent focus, extensive cloud cover from upstream convection and some impediment to stronger deep-moisture advection from MCS cold pool from lower MO Valley region to our southwest. Latest surface analysis indicates a cold front entering far northwest and western IL however, which should result in an increase in low-level forcing and shower/thunderstorm coverage heading into the late evening and early overnight hours. DVN 00Z RAOB indicates an impressive 3200 J/kg MUCAPE and 30 kts of effective shear, which would continue to support some storm organization and a severe threat (wind/hail) for any cells that can persist for a while. So far, updrafts have struggled to maintain west of and over our western cwa, though we'll continue to monitor those trends. Any severe threat should end from west to east with the passage of the surface cold front later this evening around Rockford and around/after midnight for Chicago and our southeastern counties. Locally heavy rainfall will also need to be monitored with relatively slow cell motions and especially if any training occurs. Post-frontal showers also look to persist through daybreak or so, before finally ending early Sunday morning.

With the much smaller footprint of convective activity from this afternoon into early/mid evening had lowered pops quite a bit. Otherwise, going forecast remains generally on track overnight through Sunday - with breezy, cooler and less humid conditions.

Ratzer

DISCUSSION

Issued at 324 PM CDT Sat Jun 13 2026

Recently, a few isolated showers and storms developed across parts of LaSalle eastward into southern Kendall and Grundy counties, but have since decayed. Otherwise, we continue to monitor the threat for more substantial scattered showers and storms (some of which could be strong/severe) with a cold frontal passage this evening. Forecast guidance continues to support an uptick in scattered shower and thunderstorm development late this afternoon and evening in advance of this front. This appears plausible given that a mid-level impulse currently shifting eastward across IA will be overspreading the frontal zone as it moves into northern IL after 5 pm this evening. Additionally, low-level moisture return continues in advance of the front, and is noted by surface dewpoints already increasing into the upper 60s to near 70 in parts of northern IL.

Considering the environment in which these storms are, and will be, developing features deep-layer bulk shear in excess 35 kt, there remains a threat for some storms to become strong to severe into this evening. Accordingly, the SPC continues to have our area in a level 1 of 5 severe threat through this evening. While certainly not looking to be an outbreak of severe storms like the area experienced on Thursday, a few of the strongest storms could produce localized damaging wind gusts in excess of 60 mph and possibly a few instances of hail. The main threat of storms will end from northwest to southeast through the mid to late evening hours.

A few lingering scattered showers may linger in the wake of the cold frontal boundary for a period late tonight into early Sunday morning as the main mid-level impulse dives into the area. However, this activity is expected to quickly exit the region early Sunday, setting up a precipitation free day for the area. Temperatures will be much cooler for Sunday in the wake of this cold frontal passage, as breezy northwest winds (gusting up to 30 mph) usher in a cooler airmass. Accordingly, expect high temperatures generally in the low to mid 70s Sunday afternoon. The only real weather concern for Sunday is at Lake Michigan Beaches across northwestern Indiana, where the onshore breezy winds build waves up to 3 to 5 feet, setting the stage for a high swim risk. With this in mind, we have opted to hoist a Beach Hazard statement for our Lake IN and Porter county beaches on Sunday.

Another tranquil weather day is anticipated on Monday, though with a bit warmer temperatures. Thereafter, upper troughing, anchored by a Hudson bay area low, will support an enhanced belt of mid and upper-level northwesterly upper-level flow across the central CONUS through mid to late week. This should result in a return to a more active weather pattern again (return of showers and thunderstorms) for the middle of next week, which may drive another significant impulse into the lower Great Lakes region on Wednesday. Wednesday is thus another day to watch closely for our next potential notable severe weather threat.

KJB

AVIATION /06Z TAFS THROUGH 12Z MONDAY/

Issued at 1229 AM CDT Sun Jun 14 2026

SCTD TSRA will be south of the terminal airspace by start of the 06z TAF period. A cold front will move across the terminals during the predawn hours this morning. Some brief VFR showers may accompany this front. SCT V BKN low end VFR stratocumulus deck is expected today. Northwest winds in the wake of the front will likely become gusty later this morning and remain gusty through the afternoon. Winds and gusts will subside early this evening with skies clearing out as well.

- Izzi

LOT WATCHES/WARNINGS/ADVISORIES

IL...None. IN...Beach Hazards Statement from 7 AM CDT this morning through this evening for INZ001-INZ002.

LM...None.