Heavy Rain Expected in Kentucky and Tennessee This Weekend

Frost, ice or snow is expected Saturday to coat most of the eastern United States this weekend. But an unusual springlike surge of warmer, wetter weather into Sunday morning could mean that parts of the region will also face flooding rains, severe storms, freezing rain and, in the far north, heavy snow.

A high risk of excessive rainfall was forecast for Kentucky and Tennessee, the Weather Prediction Center said early on Saturday.

Flooding in those areas could be “life-threatening,” the center said. Widespread flash flooding was expected over parts of the lower Mississippi, Ohio, and Tennessee Valleys.

“This is unprecedented for mid-February, at least in the last 20 years,” said Phil Baker, a meteorologist with the National Weather Service in Memphis, of the rain in Kentucky and Tennessee.

By next week, more typical February weather is expected to return.

Here are the hazards to watch for.

• Flooding rain: From northeastern Arkansas to southwestern West Virginia, there is a moderate risk of excessive rainfall that could cause rivers to rise or lead to flash flooding. One to three inches of rain fell over northwest Arkansas to northwest Tennessee Friday night, and more rain is on the way.

• Severe storms: In the Deep South, primarily in northern Louisiana and Mississippi, an outbreak of severe storms that could include tornadoes and damaging winds is possible from Saturday afternoon into the evening.

• Heavy snow: Moderate to heavy snow has been hitting the Midwest, which could get up to 13 inches of snow by Sunday. It was expected on Saturday to move toward the Great Lakes through New England. Maine could see up to 19 inches of snow by Monday.

• Wintry mix: New York and other cities along the Northeast coast will see snow first on Saturday afternoon, before warm air moves in, turning the precipitation to a mess of sleet, freezing rain and then rain. Some areas, especially close to the coast, will transition quickly from snow to rain. Some moderate snow could fall across the higher elevations of the Appalachians.

The rainfall is the rarity of this mid-February storm.

The region most at risk of flooding — including Tennessee and Kentucky — is already sopping wet, with some rivers near or at flood stage after having seen weeks of recent rainfall.

This rare amount of moisture surging north is more intense than the rain that has already fallen. And some places, like Lexington, Ky., where three to five inches of rain is forecast, could break their February record for daily rainfall. (Over three inches of rain was measured there on Feb. 13, 1989.)

“Part of the problem is before this rain event even started this morning, the grounds have already been saturated from earlier rainfall,” said Mr. Baker, the forecaster. “There’s going to be river flooding that’s going to persist for days.”

As of Saturday, the heaviest rainfall was expected over northwest Tennessee and western Kentucky, Mr. Baker said, with four to six inches of rain expected. Up to eight inches of rain could fall in some isolated areas, he said.

With the ground already saturated, forecasters in places like Paducah, Ky., are especially concerned by some of the outlier rainfall amounts of up to seven inches.

“It won’t take much to produce flooding,” one forecaster there wrote, warning that the region “may have a significant flooding event on our hands.”

Forecasters in the mountainous areas in the eastern regions of the places most at risk for flooding warned that the ground had produced conditions ripe for landslides and debris flows on steep slopes around the area.

Forecasters in Charleston, W.Va., reminded residents who live on or at the base of hillsides to watch for signs of potential ground movement: trees leaning in unusual orientations, or water and mud seeping in where they are not expected.

The warmer, springlike storm is expected to move off the Atlantic seaboard by Sunday evening, and winter will return on Monday.

Temperatures will plunge to below average across the eastern United States. Snow is likely to return on Tuesday and Wednesday, coating the same areas that may potentially flood this weekend in Tennessee and Kentucky — all as a coastal storm possibly returns heavy snow back to northeast coastal cities.