A quiet and seasonable weekend across northern Illinois will give way to a potentially dangerous round of severe weather on Monday, according to the National Weather Service.

Forecasters say thunderstorms are expected to develop to the west Monday afternoon before moving east across the region from midafternoon through late evening. All severe hazards are on the table, including large hail, damaging winds, and tornadoes. The overall setup suggests storms may initially form as discrete cells before evolving into a fast-moving line, increasing the risk for widespread wind damage and embedded tornadoes.

The weather service noted the exact placement of the highest threat could still shift as the system approaches.

In addition to severe storms, heavy rainfall may accompany the system. Rainfall totals of 1 to 2 inches are possible, which could lead to localized flooding, especially in low-lying and urban areas. Forecasters also cautioned that the Rock River, Fox River, and Des Plaines River could see renewed rises if heavier rain materializes over those basins.

Ahead of the storms, the region will see relatively pleasant spring conditions. Saturday will feature a mix of clouds and sun, with highs ranging from the low 70s inland to the 50s near Lake Michigan due to persistent northeast winds. Similar temperature splits are expected Sunday, though inland areas will warm into the low to mid-70s.

After Monday’s storms, a pattern change is expected to bring cooler and drier conditions to close out April and begin May. Temperatures are projected to trend below normal through much of next week, with overnight lows potentially dipping into the 30s by late week, raising the possibility of frost.

Residents are encouraged to monitor forecasts closely and be prepared to adjust outdoor plans on Monday as conditions evolve.