textproduct: Chicago

KEY MESSAGES

- Warmer, but more active weather pattern with periods of showers and storms returns late in the weekend into next week.

- A threat for severe thunderstorms exists Tuesday and Wednesday of next week.

DISCUSSION

Issued at 250 PM CDT Fri Apr 10 2026

The gloomy, low-hanging stratus and drizzle from this morning has cleared the area but, in the wake of the departing front, a thick stratocumulus deck has filled in keeping skies cloudy. This has kept temperatures a couple of degrees cooler in spots than previously forecasted. Temperatures this afternoon are sitting in the upper 40s and lower 50s. Surface high pressure out to our west will clear up some of this cloud cover before dusk and lead to a quiet, cool night ahead as it centers itself overhead late tonight. Early morning lows are forecast in the middle 30s to near 40 degrees.

This high will scoot off to the east on Saturday making way for a storm system moving into the northern Plains. We'll see cloud cover increase during the day in advance of that system. Most of our CWA will stay dry for the entire day. Showers are expected just out to our west during the afternoon. Still being under the influence of that high with dry low level air in place, dry conditions are favored through the afternoon, though can't rule out a few showers out near the I-39 corridor. During the evening, the potential translates to north of I-80 for some showers and a couple of possible embedded thunderstorms. Highs tomorrow are forecast in the 50s and lower 60s.

Strong warm and moist advection will take place late Saturday into Sunday between the prominent high to the east and a storm system to the west spreading a reservoir of high theta-e air northward across the central CONUS. Early-summer like temperatures are expected early next week with highs on Sunday forecast in the middle to upper 70s. The earlier part of Sunday looks to be dry. Showers and thunderstorms are then expected to blossom ahead of the storm's cold front to our west and progress across our area during the afternoon and evening. Despite the warm surface temps, relatively warmer air aloft will great limit instability east of the Mississippi River. So while storms should not be severe, deep layer saturation and deep dynamic forcing could stir up some pockets of heavy rainfall. The surface cold front is progged to get hung up to our northwest Sunday night as it clings to a developing upstream cyclone off the lee of the Colorado Rockies.

We're eyeing the early to middle part of next week for the potential for severe weather around the region, especially the Tuesday to Wednesday timeframe for us locally. While that surface cold front looks to stall upstream from the area late Sunday, cooler mid-upper level air will spill across the region behind the departing jet axis Sunday night and, with continued low level warm advection, promote very steep lapse rates aloft heading into Monday. With any showers lingering into late Sunday night or early Monday, it's possible that a few of them grow into thunderstorms as instability starts to build around the area. During the day on Monday, the primary triggers for convection will remain outside of our CWA with us being locked in the open warm sector and forecast soundings maintain some BL CIN throughout the day. Nonetheless, at least isolated instances of convection will be attainable during the afternoon and evening, but coverage is highly uncertain. The higher coverage and more organized severe threat on Monday appears to be to our west and especially our north across WI where a potent shortwave will interact with the warm front during the evening. But forecast soundings would suggest that any storms that develop in our local area will too have the potential of becoming severe.

Attention then turns to Tuesday and Wednesday where the Storm Prediction center has highlighted the CWA for potential severe weather in their days 5 and 6 outlooks. A great deal of uncertainty looms around this period with disagreements from medium range guidance on how exactly this system will evolve across the region. But the idea is that we'll stay parked in the storm's warm sector into Tuesday offering yet more summer-like temperatures with highs forecast to reach the lower 80s. With the EML still overhead, high values of BL instability (>2,000 J/kg) are being modeled for Tuesday afternoon. Guidance generally has convection blossoming nearby during the PM hours as the low pressure center works into the Midwest. Additional convection then looks likely on Wednesday as the storm's cold front is anticipated to move across. While there looks to be a slight downtick in instability from Tuesday, a strong effective shear profile will accompany the front and strong to severe convection will again be possible with Wednesday's storms. Will need to keep a close eye on forecast trends through the weekend and will refine expectations as more guidance becomes available.

Doom

AVIATION /00Z TAFS THROUGH 06Z SUNDAY/

Issued at 630 PM CDT Fri Apr 10 2026

Forecast concerns include...

Wind shift to northeast early this evening. Chance of showers Saturday evening.

A lake breeze boundary is currently moving inland and will shift winds to the northeast at the Chicago terminals before dissipating with sunset. Speeds in the 10-15kt range with some higher gusts can be expected with its passage. Winds will become light easterly later this evening which may become light and variable overnight. East/southeast winds around 10kt are expected Saturday with some gusts possible in the afternoon.

There is a low chance for patchy fog overnight into early Saturday morning, especially across northwest IL and at RFD but confidence is too low for any fog mention with this forecast.

There is a low chance for showers Saturday evening, mainly across far northern IL with better chances into southern WI. With uncertainty for the southern edge of this possible activity, opted to include prob mention in the new 30hr ORD/MDW forecasts. cms

LOT WATCHES/WARNINGS/ADVISORIES

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