Forecasters at the National Weather Service (NWS) Weather Prediction Center are anticipating that four-day rainfall records could be broken this week in eight cities as an atmospheric river pummels the U.S. with heavy rain.

Why It Matters

Earlier this week, AccuWeather meteorologists warned of a 1-in-1,000-year flood posing threats to several states. An AccuWeather spokesperson told Newsweek that floods like this have a 0.1 percent chance of happening in any given year.

Myriad weather alerts and warnings remain in place across the U.S. from eastern Texas northeast through Ohio on Thursday. Meteorologists are warning of floods, severe storms and strong winds.

On Wednesday, the storms fueled tornadoes and heavy rainfall across multiple states, killing at least one person, the Associated Press reported.

What to Know

As of Thursday, numerous daily rainfall records have already been broken in multiple states. However, a much more uncommon occurrence is when a storm breaks a four-day rainfall event.

NWS Weather Prediction Center meteorologists said there are eight sites that could break the four-day rainfall record. Most of the areas have forecasted rainfall below what the record is, but NWS Weather Prediction Center senior branch forecaster Brian Hurley told Newsweek that “anything within a couple inches is fair game.”

“All we need to do is have some of these heavier rain bands shift,” Hurley said.

Cities that could see their four-day rainfall records broken include:

• Little Rock, Arkansas: The four-day rainfall record is 12.53 inches. The forecast is 10.45 inches.
• Memphis, Tennessee: The four-day rainfall record is 13.59 inches. The forecast is 12.25 inches.
• Paducah, Kentucky: The rainfall record is 10.17 inches, and the forecast is 10.18 inches.
• Nashville, Tennessee: The four-day rainfall record is 13.57 inches, and the forecast is 8.22 inches. If one of the rain bands shifts over Nashville, it could break the record.
• Louisville, Kentucky: The record is 13.04 inches, and the forecast is 8.67 inches.
• Jonesboro, Arkansas: The record is 9.07 inches, the forecast is 10.25 inches.
• Booneville, Arkansas: The record is 9.23 inches, and the forecast is 7.83 inches.
• Mena, Arkansas: The record is 13.16 inches, and the forecast is 13.51 inches.
• Pine Bluff, Arkansas: The record is 10.2 inches, and the forecast is 10.17 inches.

Hurley said breaking four-day rainfall records doesn’t occur frequently.

“It is a very significant event,” he said.

What People Are Saying

NWS office in Memphis, Tennessee, in a flood watch: “Multiple rounds of heavy rainfall will compound the flash flooding threat today through early Sunday morning. Rainfall totals will approach 12 to 15 inches for areas north of I-40 through Sunday with 5 to 10 inches to the south.”

NWS office in Paducah, Kentucky, in a flood watch: “Showers and storms through today produced 1 to 4 inches of rainfall across the Quad State. With another 5 to 9 inches of rainfall forecast through Sunday, a particularly dangerous flooding and flash flooding situation is expected.”

What Happens Next

Rounds of heavy rainfall will continue to pummel the Midwest and South through Saturday night. Any rivers that flood could remain flooded into early next week, as it takes time for the water to recede.