US: Adverse weather forecast across the South and Southeast regions through at least March 17 /update 1

Severe weather is forecast across parts of the South and Southeast regions through at least March 17. Waves of low pressure and an associated cold front are expected to bring heavy rainfall and thunderstorms across the region over the coming days. Strong winds, lightning, hail, and possible tornadoes may accompany storms. Heavy downpours may trigger flooding in low-lying areas, and strong winds may cause property damage and power outages.

As of March 15, the US National Weather Service (NWS) has issued severe thunderstorm warnings and watches for parts of south-central Texas, eastern Mississippi, central Alabama, and far northwestern Georgia. Flash flood warnings are in place for parts of far northeastern Texas, far northwestern Louisiana, and southern Arkansas. Authorities will likely issue new alerts as weather conditions change over the coming days.

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 south-central Texas March 15 and a slight risk for surrounding areas of southern and central Texas and for parts of eastern Mississippi and central Alabama.

The NWS's Weather Prediction Center has forecast a slight risk of excessive rainfall (the second lowest level on a four-tier scale) for parts of south-central Texas and from far southeastern Arkansas eastward across central Mississippi and central and northern Alabama into northwestern Georgia March 15-16. There is a further slight risk of excessive rainfall for parts of south-central and eastern Texas March 16-17.

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 likely where significant flooding or landslides impact utility networks.

The severe weather will likely 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 will likely 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 probable in areas with heavy rainfall and potential track inundation.

Localized business disruptions will likely 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.