Strong Storms Bring a Threat of Tornadoes on Thursday

Two fast-moving storm systems that are sweeping across central and northeastern parts of the United States will bring rounds of severe thunderstorms with the potential for tornadoes, damaging winds and large hail through Friday.

The severe weather threat is expected across a broad stretch of the country, from the southern Plains into parts of the Midwest, with the highest risk areas over parts of Iowa, Missouri, Illinois, Wisconsin and Michigan, said Matt Mosier, a meteorologist at the Storm Prediction Center.

“The tornado threat will probably be concentrated mostly over eastern Iowa and the north of Illinois,” he said. “There’s also the risk of damaging winds across a large portion of that area.”

Large hail is also expected, particularly on Friday, where parts of the southern Plains could see hail greater than two inches in diameter, Mr. Mosier said. That’s about the size of a lime.

The storms are also forecast to produce heavy rainfall that could lead to flash flooding, especially across parts of Texas, Oklahoma, Arkansas and Missouri on Friday. The Weather Prediction Center said one to three inches of rain was expected, with isolated totals of four to seven inches possible.

Here’s what to expect:

Thursday

Severe thunderstorms are expected across the Midwest, especially over parts of Iowa, Illinois, Wisconsin and into Michigan.
Strong tornadoes are possible in these areas, beginning Thursday afternoon, along with damaging winds that could include gusts in excess of 75 miles per hour by Thursday evening, particularly over eastern Iowa into Michigan.
Hail is possible, though it is not expected to exceed two inches in diameter.
Farther south, across parts of Arkansas, Missouri, Tennessee and Kentucky, isolated thunderstorms may develop during the afternoon.

Friday

Severe thunderstorms are expected to develop again over the southern Plains to the Midwest during Friday afternoon and continue into the evening, with the highest risk across northern Missouri and southern Iowa.
Damaging winds are one of the primary threats, especially from Texas and Oklahoma through to areas of Iowa and Illinois, with gusts in excess of 75 m.p.h.
Hail larger than two inches in diameter is expected.
Isolated tornadoes are also a possibility, especially in areas of Oklahoma, Arkansas, Missouri, Iowa and Illinois.
Some storms may produce high rainfall totals, bringing the risk of flash floods, particularly across parts of Texas, Oklahoma, Arkansas and Missouri.

Mr. Mosier said the severe weather risk was expected to diminish through the weekend, with “stable conditions” developing through at least the middle of next week.