Thursday is a First Alert Day across southern Wisconsin as a significant severe weather setup is expected to bring multiple rounds of storms from early afternoon into early evening. Forecasters say all major hazards are possible, including isolated tornadoes, damaging winds and large hail. A strong weather system moving from Kansas into northeast Iowa and then east-central Wisconsin will pull warm, humid air northward ahead of it, creating an environment favorable for dangerous storms.
The first round of thunderstorms may form late Thursday morning into early afternoon. These initial storms could already produce large hail as they move through the region. The main threat is expected later in the day, during the afternoon and early evening hours, when conditions become more favorable for severe storms across southern Wisconsin. Meteorologists say the atmosphere will be primed for rotating storms thanks to strong winds at multiple levels, and both isolated supercell thunderstorms and organized line segments are possible.
Heavy rainfall will also be a concern. With moisture levels running high, the storms may produce intense downpours that could lead to flash flooding, especially in urban areas where water tends to collect quickly and cannot soak into the ground easily. Some storms could become strong enough to cause significant damage.
Conditions are expected to improve after the storms move out Thursday evening. Behind the system, winds will shift to the west and cooler air will move into the region. Temperatures are expected to fall into the 50s by Friday morning. Friday should bring a quieter stretch of weather, with dry conditions, light west winds and temperatures near seasonal normals for mid-June as high pressure briefly builds in.
The break in active weather will not last long. Another chance for showers and thunderstorms is forecast for Saturday as a weak system approaches from the west during the afternoon and continues through Saturday night. Scattered showers and storms are possible throughout the day.
Looking farther ahead, early next week is expected to turn cooler than normal with periodic chances for showers. A larger weather system is forecast to settle over Ontario, keeping shower chances in the forecast through Wednesday and maintaining below-average temperatures across the area.
Residents across southern Wisconsin are being urged to stay alert throughout Thursday as the severe weather threat unfolds. The combination of tornado potential, damaging wind, large hail and heavy rain makes this a day to monitor weather updates closely, especially during the peak afternoon and evening hours.
