Two rounds of severe thunderstorms moved across portions of the Midwest from the morning into the overnight hours of March 14, 2024. The initial round moved across Illinois and Indiana during the morning into the afternoon hours.

This line prompted Severe Thunderstorm Warnings and Tornado Warnings in the St. Louis area as early as 7:30 am CDT. Additional Tornado Warnings were issued across Illinois with Severe Thunderstorm Warnings later issued in the Indianapolis, Indiana area.

Behind the initial round of rain and storms, skies rapidly cleared out as a 700 mb dry slot punched in. This allowed additional thunderstorms to form around 4:30 pm EDT across north-central Indiana near the Lafayette area. Storms would continue to develop along the frontal boundary into the evening, prompting warnings from Illinois eastward across Indiana, and into Ohio.  

In total, there were 816 severe weather reports from the Southern Plains into the Ohio Valley with 36 tornado reports. Several tornadoes impacted eastern Indiana and Ohio at EF-1 to EF-3 strength. The strongest was an EF-3 tornado that hit Winchester, Indiana at 7:37 PM EDT with winds of 165 mph before moving to the east into Ohio. 38 injuries were reported with this tornado. Another EF-3 tornado with winds of 155 mph impacted Auglaize and Logan County Ohio. Significant damage occurred with this tornado, as well as 3 fatalities and 27 injuries.

A quick-moving round of snow impacted portions of the Upper Midwest from late in the evening on March 21st through late night on March 22nd. This occurred as a strong temperature difference created a couple of areas of strong frontogenesis (the change of magnitude or orientation of the front). This prompted Winter Weather Advisories to be issued across portions of Minnesota, northern Iowa, northern Illinois, Wisconsin, and central Michigan.

During the morning hours of March 22nd, a heavy band of snow was developing across northern Iowa, southern Wisconsin, and northern Illinois. The Storm Prediction Center issued a Mesoscale Discussion (MD) at 10:15 am CDT for this area as snowfall rates of 1-2” were occurring!

The heaviest banding developed across northern Illinois and far southern Wisconsin through the morning where 1”/hr rates were reported. The NWS upgraded the Winter Weather Advisories to Winter Storm Warnings for McHenry, Boone, Winnebago, Stephenson, Ogle, Carroll, and Jo Daviess counties in Illinois. Winter Storm Warnings were also issued for Jackson, Dubuque, and Jones counties in eastern Iowa.

Much of the heavier accumulation across the Upper Midwest had ended by early afternoon on March 22nd. However, minor accumulations continued into the late afternoon and evening across northern Illinois and Michigan. Overall, two bands of heavy snow were reported, one further north running from just north of the Twin Cities east to Green Bay, Wisconsin.

The greater swath extended across central Iowa into northern Illinois and southern Wisconsin. Up to 9.1” of snow was reported in Cherry Valley, Illinois (near Rockford) with up to 12” of snow reported near Milwaukee, Wisconsin. The band itself was very narrow, with the northern end of McHenry County Illinois seeing 8.1” and the southern edge of the county seeing 0.50-1.50” of snow in only an 18-mile difference!

A major winter storm impacted portions of the Upper Midwest from March 25-27th. An impressive upper-level trough allowed for the strengthening of a low-pressure center across the Great Plains, with the pressure falling from 991mb to 989mb as it moved into west-central Wisconsin on March 26th.

Winter Storm Warnings were issued across much of Minnesota and Wisconsin. Blizzard Warnings were issued along the North Shore of Minnesota from Two Harbors to Grand Portage, as well as across portions of Colorado, Nebraska, and South Dakota.

Periods of 1.00-1.50”/hr snowfall rates occurred late on March 24^th into the 25^th across portions of eastern Minnesota and northern Wisconsin. The long-duration snowfall event continued across the region through late on March 27, 2024.

A widespread area of heavy snow accumulated across Minnesota, northern Wisconsin, and the Upper Peninsula of Michigan. Snowfall amounts of 18-25” were reported across the Arrowhead of Minnesota. Areas in northern Wisconsin reported 12-17” of total snowfall.