The Washington PostDemocracy Dies in Darkness

Flooding rains hit Deep South with more soaking storms on the way

Many places have already quadrupled their average February rainfall

The European model's simulation for heavy rainfall through Saturday. (Weatherbell)

The latest in a series of heavy rain events is deluging the Deep South and Southeast. Rain totals in some spots have surged to more than four times typical February averages despite being barely a third of the way through the month. More rain is en route later this week, sparking flooding concerns amid a shot at some severe thunderstorms.

Roads were inundated and water rescues were needed Sunday afternoon as nearly 8 inches of rain swamped parts of Tuscaloosa County in Alabama. Numerous vehicles succumbed to high water, while schools closed early on Monday in Birmingham. A number of trees also toppled, their roots easily freed from a thick goop of soggy soil. Many schools in Alabama opened Tuesday with a two-hour delay.

Accumulating water also elevated concerns at several dams in Alabama and Mississippi. ABC 33/40 out of Birmingham reports a swollen Coosa River prompted officials at Alabama Power to recommend residents downstream of the Lay Dam “pay close attention.”

In Mississippi, the Oktibbeha County Lake dam is at risk of a breach, the recent heavy rainfall leading emergency managers to place the dam in “watch” status.

A high risk of excessive rainfall was posted on Monday for parts of the Interstate 20 corridor in Mississippi and Alabama. Instances of “life-threatening flooding” were anticipated as some areas experienced deluge upon deluge beneath the slow-moving slug of downpours. Flash flood warnings blanketed the map.

In Birmingham, nearly 8 inches of rain has come down since the start of February, roughly five times the typical norm. Huntsville is up to 4.77 inches, while Tuscaloosa has eclipsed 9.5 inches — 4.5 of which fell on Monday alone.

It’s been equally wet in neighboring Mississippi, where Meridian is up to 5.75 inches. And in Winston County, some 6.21 inches poured down in a mere 24 hour period ending around sunrise Tuesday morning.

With the instigating system on the move, another will work in to replace it, bringing even more rainfall. Many locations in the South and Southeast could add another 2 to 4 inches to their rainfall totals by the end of this week.

The axis of heaviest rainfall in Alabama should shift south of the Birmingham metro on Tuesday as the cold front that gave rise to it translates east. While showers are possible for portions of Alabama, Georgia, the Smokey Mountains and the Carolina Piedmont, the area most likely to pick up an inch or two looks to encompass southern/southeastern Virginia.

Meanwhile, another glob of heavy rainfall is brewing, this time in East Texas. The weather pattern carries with it a connection to moisture in the subtropical Pacific, while low-level moisture continues to stream in from the Gulf of Mexico. Simultaneously, a dip in the jet stream wrapped about a lobe of high-altitude chilliness will incite widespread lifting motion, generating heavy rainfall.

As moderate rain continues to fall to the east over Mississippi, Louisiana and Alabama on Tuesday and Wednesday, that upper-level support will invigorate the developing downpours over central and East Texas. The National Weather Service has designated a slight risk of excessive rainfall there.

Eventually, the sloppy conglomerate of rain will organize along an incisive cold front sweeping in from the lower Mississippi Valley. Wednesday will feature a chance of strong to isolated severe thunderstorms over Louisiana, Mississippi, Alabama and Tennessee. While a swath of 50 to 60 mph winds and an isolated tornado threat will be present, the areal coverage of such instances may be on the lower side due to uncertainty in the amount of instability present.

Instability, which gives rise to storms, is a function of how warm the air feeding said storms can get. With low clouds expected to dominate across the South from Tuesday into Wednesday, it’s unlikely there will be much sunlight/solar heating to add any extra fuel to the fire.

By Thursday, another inch of rain is possible over southern/eastern Tennessee, Mississippi, Alabama and western Georgia.

It’s been a rainy start to the year for much of the South and Southeast, where a number of cities have emerged into their top 5 wettest starts to the year on record.

The long-term pattern favors additional systems packed with heavy rain and isolated bouts of severe weather to continue for the South. The next looks to occur in about a week’s time, spanning form Feb. 17-19 in Texas, Arkansas and Louisiana to perhaps Feb. 19-21 in the Southeast. While those dates may shift, the pattern suggests another waterlogged weather-maker around that time.