Tropical Storm Bertha is fading, but its moisture plume is fueling a serious East Coast flood threat

[Breaking news update, published at 2:05 p.m. ET] Tropical Storm Bertha had moved inland as of 2 p.m. ET, according to the National Hurricane Center, and is now over the Texas-Louisiana border. The storm had maximum sustained winds of 45 mph, according to the center’s update. Bertha is expected to dissipate by Friday morning as it tracks farther inland. Major impacts are not expected in Texas, but the storm is kicking up winds on the coast and fueling showers and storms deep into South Texas. [Original story below, published at 12:59 p.m. ET] Bertha will make its final landfall on the northwest Gulf Coast later Thursday, bringing with it tropical storm-force wind gusts and rainfall to parts of the Texas and Louisiana coastlines. But its most widespread flooding rain threat is unfolding hundreds of miles away in the East. The disorganized, lopsided tropical storm was centered just south of the southwest Louisiana coast late Thursday morning with maximum sustained winds of 45 mph. Bertha is expected to reach the upper Texas coast by late Thursday afternoon or early evening before moving farther inland over Texas by Thursday night. 🌀 ⛈️ Get your storm forecast in the CNN Weather app Meanwhile, a plume of tropical moisture linked to Bertha is feeding soaking rain along a cold front draped across the Southeast. That moisture will continue to supercharge a flooding rainfall threat through Friday from North and South Carolina to northern parts of Georgia and Alabama, potentially producing more flooding impacts than those occurring near Bertha itself. Some areas in North Carolina have already received a month’s worth of rain in just a few days with more to come. Heavy rain Thursday morning prompted flash flood warnings in southeast Virginia, eastern North Carolina and eastern Tennessee. Flooding closed a short section of Interstate 40 northwest of Durham, North Carolina, Thursday morning that has since reopened, according to the state’s department of transportation. Flash flood warnings were also issued in north-central North Carolina, including Greensboro and Winston-Salem, Wednesday night, where heavy storms dropped up to 6 inches of rain in 12 hours. There were no flood reports from the area, where a serious drought and prolonged, rather than intense, rainfall has helped mitigate the threat so far. Bertha’s Texas threats Bertha is forecast to maintain tropical storm strength until it reaches the upper Texas coast late Thursday, then dissipate over Texas by Thursday night or Friday. Bertha’s uneven structure, with its storminess mostly over the Gulf, means its tropical storm-force wind gusts will impact the upper Texas Coast and southwest Louisiana, while much of its rainfall goes toward South Texas. A tropical storm warning for sustained winds of 39 mph or greater is in effect from the upper Texas Coast, including Galveston, to south-central Louisiana, where tropical storm conditions are expected Thursday. Farther south, the storm could bring 2 to 4 inches of rain, with isolated totals of 6 inches, to a few areas along the middle Texas Gulf Coast and in South Texas through Thursday night. Isolated flash flooding is possible, but dry ground conditions should help combat a bigger threat. Bertha is the second named storm of the Atlantic hurricane season, which has gotten off to a slow start compared to recent years as El Niño tightens its grip on parts of the basin. Multiday flood threat in the East Bertha’s moisture began funneling into a slow-moving front draped across the Southeast and southern Virginia in earnest on Wednesday, setting the stage for the ongoing flood threat. On Wednesday morning, storms caused flash flooding north of Knoxville, Tennessee, after up to 5 inches of rain fell in a few hours. More rounds of rain are expected through Friday. The Carolinas need rain to help quench drought conditions there, but too much rain repeating over the same areas over hours or days could quickly trigger dangerous flash flooding. A Level 2 of 4 risk of flooding rain is in place from parts of the Carolinas westward to northern Alabama Thursday into Friday morning. Thursday afternoon’s thunderstorms could pack rainfall rates up to 2 inches per hour — an intensity that can quickly overwhelm drainage systems and flood urban areas. Atlanta, Birmingham, Alabama, and Charlotte, North Carolina are among the cities at risk. The flood threat will continue Friday, with a Level 2 of 4 risk stretching from coastal North Carolina through South Carolina, northern Georgia and into northeast Alabama.