Heavy rain showers and thunderstorms are forecast to deliver as much as three inches of rain across the Chicago area this weekend, prompting an elevated flood risk. The precipitation is expected to begin early Saturday, September 19, 2026, and continue through Sunday, September 20, 2026.
Pete Sack of the NBC 5 Storm Team reported that a series of storm systems moving into the region will generate the heavy rain. He noted that the combined moisture from these systems is sufficient to produce the forecasted totals and that the timing aligns with the typical early‑season rain pattern.
Meteorologists say the incoming storm systems are part of a broader weather pattern that has been bringing moisture from the Gulf of Mexico into the Midwest. As these systems converge over northeastern Illinois, they are expected to intensify, producing sustained rain bands that will affect much of the metropolitan area.
The forecast highlights particular concern for traffic corridors along Interstate 57 and Interstate 55, where runoff could accumulate quickly. The combination of saturated ground from the first round of rain and additional showers later in the day may lead to localized flooding on these highways and adjacent low‑lying streets.
The first round of heavy rain is slated to begin early Saturday, bringing the initial inch or two of precipitation. A second round is projected for later Saturday night and into Sunday, potentially adding another inch to the total. Residents in neighborhoods near the I‑57 and I‑55 corridors are advised to monitor road conditions and be prepared for possible delays.
Overall, the weekend’s weather outlook calls for continued vigilance as the series of storms moves across the Chicago region, delivering up to three inches of rain and raising the likelihood of flash flooding in vulnerable areas.