The air has been sticky, with temperatures rising through the afternoon each day before the clouds start to appear. By evening, the phone alerts begin to sound, announcing warnings of thunderstorms that could bring giant hail, damaging winds, flash floods or even dangerous tornadoes.
Wisconsin, like nearly every other state between the Texas-Mexico border and the Great Lakes, has endured a daily barrage of weather warnings since Sunday: 32 for tornadoes, 108 for severe thunderstorms and 62 for flooding. Local forecasters have called the level of severe weather “unprecedented” in the state, and on Friday they were bracing for more as yet another storm system trudged across the Midwest.
Friday is going to be a “repeat performance of everything that’s been occurring,” said Mark Garing, a senior meteorologist for the National Weather Service office in Milwaukee.
Bryan Smith, a meteorologist at the Storm Prediction Center, said the latest storms were expected to begin developing on Friday afternoon, with a “pretty extensive band of storms” expected by the evening and continuing into the night. The areas facing the highest risk include parts of Oklahoma, Kansas, Missouri, Iowa, Illinois, Minnesota and, once again, Wisconsin.
It is not unheard-of for the Midwest to experience severe, dangerous storms like this. Wisconsin typically gets 23 tornadoes per year, with most occurring during the typical peak in July. This is just the wrong time of the year for them.
“It’s like a week — a week’s worth of summer, but even for summer, the amount of severe weather and flooding we’re having, this is high-end,” Mr. Garing said. “It rivals anything, even in summer.”
Tornado counts are often preliminary. But of the 13 that have been reported in Wisconsin this week, seven have already been confirmed by local investigators. The strongest was rated a three on the five-point enhanced Fujita scale, with winds of up to 140 miles per hour that over the course of 20 minutes carved a nine-mile path near Hillsboro, Wis., destroying buildings and uprooting trees. There were no reports of injuries.
“Typically, severe weather in early to mid-April is most common farther south, across the southern Plains and Southeast portions of the country,” said Bill Bunting, deputy director of the Storm Prediction Center.
The Plains, too, had tornadoes this week. An EF-2 struck Ottawa, Kan., on Monday night, damaging several businesses and homes, and at least three people were injured.
On Friday, Mr. Smith said the greatest risk for tornadoes was expected from northeast Iowa into central Wisconsin, though he added that tornadoes could occur anywhere from Oklahoma into the Upper Midwest and the Great Lakes.
The storms could also bring very large hail — “on the order of two to three inches, maybe 3.5 inches in diameter,” Mr. Smith said — and powerful straight-line winds that could reach up to 80 m.p.h.
Flash flooding will be an added threat on Friday. Forecasters highlighted an area stretching from northeast Oklahoma up to Iowa and northern Illinois as being at the greatest risk. Heavy rainfall totals of up to two inches are possible, with isolated areas potentially receiving more than three inches.
Flash flooding on Wednesday night stranded drivers in Milwaukee, briefly shutting down a major highway running through the city. Overall, the city recorded 7.57 inches of rain this month, setting a new monthly record barely two weeks in. In Michigan, the recent heavy rain has contributed to a what one local lawmaker called a “slow-moving disaster” as several dams across the state have struggled to hold back rising waters.
Thunderstorms can occur nationwide throughout the year, but they are most common in the late afternoon and evening during the warm months. Predicting when, exactly, a typical springtime storm will turn into something more dangerous — by producing a tornado or a torrent of heavy rain — can be difficult.
Overall across the country, this season’s severe storms have averaged near normal, Mr. Bunting said, noting that “what is typically the most active time of the year” — late April and May — is still ahead.
Texas has so far experienced the most days of active severe storms, but Illinois and Indiana are in a close second with at least a dozen each. Illinois has had more preliminary tornado reports this year than any other state, with 65. The state’s local Weather Service offices have also issued more than 80 warnings for tornadoes this year and are likely to add more to the total on Friday.
As the stormy days pile up, forecasters and emergency officials worry about fatigue. “We want it to end because, yeah, people are getting tired,” Mr. Garing said.
In Oklahoma, where back-to-back days of severe storms occur with frequency, the Weather Service has even put together a guide for coping with “storm anxiety.” It urges people to have a plan ready for when storms hit as a way to feel in control when the weather suddenly turns dangerous.
Mr. Garing said forecasters were expecting the weather to begin calming down after Friday, at least for a few days.
“We are trying to get the message out that Friday’s risk is the last for a while,” he said.
How to prepare
Judson Jones is a meteorologist and reporter for The Times who forecasts and covers extreme weather.
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