US: Adverse weather forecast to continue across southern and southeastern regions through at least early May 11 /update 3

Severe weather is forecast to continue across parts of the southern and southeastern US through at least early May 11. Severe thunderstorms and heavy rainfall have been impacting parts of the central and southern US in recent days, leading to tornado damage, power outages, and flooding in places. The threat of severe storms accompanied by strong winds, hail, and possible tornadoes is likely to persist over the region regions May 10 and overnight into early May 11. Further downpours could trigger flooding in areas where the ground is already saturated, and river levels are high following previous heavy rainfall over the recent weeks. Strong winds may cause property damage and power outages.

As of early May 10, the US National Weather Service (NWS) has issued severe thunderstorm warnings for parts of southern Mississippi and severe thunderstorm watches across parts of southeastern Louisiana, southern Mississippi, southern Alabama, southeastern Georgia, and the western Florida Panhandle. Flood warnings are in place for multiple river basins across the affected area. Authorities will likely issue new alerts as weather conditions change over the coming days, including short-term tornado and flash flood warnings.

The NWS's Storm Prediction Center has warned of an enhanced risk of severe thunderstorms (the middle level on a five-tier scale) for parts of central and eastern Texas, Louisiana, central and southern Mississippi, central and southern Alabama, southeastern Georgia, and northwestern Florida May 10. There is a slight risk of severe storms for surrounding areas from central Texas eastward to the Atlantic coast in far southeastern South Carolina, Georgia, and northeastern Florida. There is a further enhanced risk of severe storms over parts of far southern Georgia and northern Florida May 10-11 and a slight risk of severe storms for surrounding areas of north-central and northwestern Florida, southern Georgia, and southern South Carolina. There is a separate area with a slight risk of severe storms over parts of northeastern South Carolina and southeastern North Carolina May 10-11.

The NWS's Weather Prediction Center has warned of a slight risk of excessive rainfall (the second lowest level on a four-tier scale) for a wide area from central Texas eastward across eastern Texas, central and northern Louisiana, far southeastern Arkansas, central and southern Mississippi, central and southern Alabama, and into southern Georgia and northern Florida May 10.

Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rainfall has saturated the soil.

Authorities could issue mandatory evacuation orders for flood-prone communities over the coming days. Disruptions to electricity and telecommunications services are possible where significant flooding or landslides impact utility networks.

The severe weather could contribute to transport disruptions throughout the region. Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities will probably temporarily close low-lying routes that become inundated by floodwaters.

Severe weather may cause flight delays and cancellations at airports across the affected region. Flooding could block regional rail lines; freight and passenger train delays and cancellations are possible in areas with heavy rainfall and potential track inundation.

Localized business disruptions will probably occur in flood- or tornado-hit areas; some businesses might not operate at full capacity because of damage to facilities, possible evacuations, and some employees' inability to reach work sites.