textproduct: Chicago

KEY MESSAGES

- Rain ends from northwest to southeast this morning.

- 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 330 AM CDT Fri Apr 10 2026

Rain continues to move across the area from northwest to southeast early this morning amidst strong low-level warm and moist advection. So far, rainfall rates have remained largely in check and should limit the overall flooding impacts other than localized ponding and minor rises on already elevated creek and stream levels. There remains a signal for a narrow ribbon of weak instability moving into areas south of the Illinois/Kankakee River Valleys which could support a few embedded lightning strikes early this morning. Hi-res guidance also hints at the potential for locally gusty winds reaching the surface from the strong low-level jet overhead in those areas early this morning, potentially aided by gravity waves that have developed ahead of the band of showers.

In the wake of this morning's showers, a cooler day is in store today compared to yesterday with lingering cloudy skies and cooler northerly flow holding temperatures in the upper 40s to mid 50s north of I-80 (cooler near the lakeshore), and upper 50s to around 60 toward central Illinois. Also expect temperatures to drop steadily in the wake of a lake breeze this afternoon into the upper 30s and lower 40s by this evening as it pushes well inland.

Surface high pressure currently over the north central Plains will translate east toward the western Great Lakes today and settle over the region overnight. This will bring a temporary break in the precipitation chances through at least the morning on Saturday. Warm advective showers and storms that develop overnight across Iowa will be in a decaying phase as they approach the area into the afternoon on Saturday. Suspect much of the area will remain precipitation-free through the afternoon given the dry low-levels in place amidst the broader surface high in place. However, a few showers may manage to persist into the area in the evening, mainly north of I-80. Southeasterly winds on Saturday will hold high temperatures in the 40s to lower 50s across far northeast Illinois with upper 50s to lower 60s expected south of I-80 and well inland in northern Illinois.

A broader pattern shift will be well underway heading into next week with upper troughing becoming established across the western CONUS. In additional to much warmer (70s/80s temperatures) and more humid conditions (60s dewpoints) here locally, this will facilitate the ejection of several mid-level impulses across the Plains toward the Upper Midwest leading to several days of convection. We will initially be on the eastern periphery of this activity, and associated severe weather potential, which will nudge closer to the area with each passing day next week.

Sunday will feature strong warm and moist advection into the region with winds gusting up to 30-35 mph. Temperatures are currently forecast to warm into the mid-to-upper 70s. However, if there is thicker cloud cover in place overhead this may be a few degrees too high. There will also be increasing potential showers and some embedded thunderstorms late Sunday afternoon into Sunday night. Given overall weak mid-level lapse rates forecast, this may serve to limit thunderstorm coverage, and severe weather is not currently expected with this activity.

At this distance Tuesday and Wednesday still appear to have the best potential for severe weather here locally (also noted in SPC long-range outlooks) paired with heavy rainfall. Still a lot of details to iron out at this distance though. Stay tuned!

Petr

AVIATION /06Z TAFS THROUGH 12Z SATURDAY/

Issued at 1247 AM CDT Fri Apr 10 2026

Main Items of Note:

- Rain and associated VSBY reductions early this morning, heaviest at RFD where VSBY may get as low as 1SM at times.

- After the heaviest rain moves out, a likely period of IFR CIGs will be accompanied by scattered SHRA and reduced VSBY in BR.

- Winds will likely trend to north-northwest this morning and then return to northeast this afternoon behind a lake breeze.

Heavier (2-3SM VSBY) rainfall has finally moved into the RFD area as of this writing, and will take a few more hours to reach Chicagoland. IFR VSBY in heavier rain rates may only be temporary for the Chicago metro terminals though. CIGs should deteriorate during the rain and then in the showery/drizzly/foggy regime behind it, trend down to prevailing IFR. Given some timing uncertainty with CIG category trends through the day today, didn't make big changes from previous issuances. Confidence is high in VFR by this evening.

Generally north to northeast winds overnight/early this morning now appear likely to veer to west of north by or after daybreak. A lake breeze will shift directions back to northeast as it pushes inland this afternoon, with wind specifics likely needing refinement per guidance and observational trends.

Castro

LOT WATCHES/WARNINGS/ADVISORIES

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