Heavy Rains and Flash Floods Threaten Midwest and Ohio Valley

Weather|Heavy Rains and Flash Floods Threaten Midwest and Ohio Valley

Severe, slow-moving storms are expected to sweep across Illinois and Indiana on Sunday, with some areas potentially getting up to 11 inches of rainfall, significantly raising the risk of flash flooding, forecasters said.

The threat stems from a cold front moving into the region, particularly in the afternoon, and stalling there, creating conditions for repeated rounds of storms that could unload torrential rains.

The Weather Prediction Center has issued a Level 3 out of 4 risk for excessive rainfall across central Illinois.

The center said rainfall rates could reach three to four inches per hour, and up to eight inches in some areas.

Frank Pereira, a meteorologist at the Weather Prediction Center, said that a significant amount of atmospheric moisture was contributing to the risk of intense rainfall.

“Typically during the summer, we get warm humid air masses,” he said. “But this is on the higher end of that.”

A Level 2 out of 4 risk for flash flooding extended from eastern Iowa and northern Missouri to western West Virginia and as far south as northeast Georgia and western North Carolina. Much of this region was under multiple flood watches on Sunday.

Damaging winds, hail, tornadoes and other types of severe weather were also a concern.

The Storm Prediction Center placed central Illinois, Central Indiana, southern Ohio, northern Kentucky and southeastern West Virginia under a Level 2 out of 5 risk for severe storms on Sunday.

The main threats included strong, potentially damaging winds and isolated hail. There was a low risk for tornadoes.

The risk of flash flooding was expected to persist into the week.

“Indiana, Kentucky, Tennessee, there’s a concern the storms in those areas may be impacted by more additional heavy rains going into Monday,” Mr. Pereira said. “So if you get back-to-back or repeated storms, that could really elevate flooding concerns.”

The Weather Prediction Center has issued a Level 2 out of 4 risk on Monday for excessive rainfall across those states, as well as for southwestern West Virginia and the far west of Virginia.

The ground will already be saturated from Sunday’s storms, forecasters said, and additional rainfall could reach up to three inches an hour, and locally as much as five inches, causing conditions ripe for flash flooding.