Summer Heat to Fuel Powerful Midwest Storms | WeatherBug
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Summer Heat to Fuel Powerful Midwest Storms

June 18, 2021
UPDATED By WeatherBug's Intern Meteorologist, Christopher Smith
After a brief lull, severe weather returns to the Upper Midwest this afternoon. Damaging winds, large hail and a few tornadoes are possible.

The trigger for this new round of storms will be a cold front pushing toward the Lower Great Lakes. In combination with a low-pressure centered over the Upper Midwest and sultry summer air, robust thunderstorms will develop later today.

This morning, storms are diminishing as they move across Iowa. Convective inhibition will limit storm development to isolated thunderstorms in the early afternoon, but the cold front will be the trigger for more widespread, powerful storms to develop by late afternoon.

Storms late this afternoon may start out in the form of supercells with the primary threat of very large hail across southern Minnesota and northern Iowa. However, by evening, the storms may form into a squall line, packing damaging wind gusts from northeastern Iowa into southern Wisconsin and northern Illinois.

There is still uncertainty for how far to the east and southeast the severe threat will extend, but Des Moines, Iowa, La Crosse, Wisc., and Peoria, Ill., will all need to be on the lookout for storms today. A few big storms could make their way into Milwaukee and Chicago late this evening into the overnight.

Multiple Severe Thunderstorm Watches have been issued by the Storm Prediction Center (SPC) for parts of northern Iowa, southern and eastern Wisconsin and southern and central Minnesota. Primary threats include scattered damaging winds with significant gusts of up to 80 mph possible, very large hail of up to two diameters, and a possible tornado or two. Cities within the watchbox include Minneapolis, Waterloo, Iowa, and La Crosse, Wis.

Understand the difference between a watch and a warning. A watch means conditions are highly favorable for dangerous weather, and you should have a plan in place for acting. A warning means that dangerous weather has been observed, and you need to act quickly to protect life and property.

Remember, lightning is one of Mother Nature’s most deadly killers. If you are close enough to a storm to hear thunder, you are close enough to be struck by lightning, even if the sun is still shining.