US: Adverse weather forecast to continue across southern regions through at least early May 29 /update 4

Severe weather is forecast to continue across parts of the southern US through at least early May 29. Severe thunderstorms and heavy rainfall have been ongoing across parts of the central and southern US in recent days, leading to casualties, damage, and disruptions in places. As of early May 28, at least 21 fatalities have been reported across Arkansas, Kentucky, Oklahoma, and Texas in areas hit by tornadoes and storms. Tens of thousands of customers are without power across the affected regions due to the severe weather. Further storms and isolated heavy downpours are forecast across much of Texas and surrounding parts of the southern US May 28 and into early May 29, with the most severe weather likely in areas just west of Dallas-Fort Worth and north of Austin. Strong winds, lightning, hail, and possible tornadoes may accompany storms. Heavy downpours may trigger flooding in low-lying areas, especially in areas where river levels are high and the ground is saturated from previous heavy rainfall. Strong winds may cause property damage and power outages.

As of early May 28, the National Weather Service (NWS) has issued severe thunderstorm warnings and watches across parts of northern Texas and southern Oklahoma. Flood warnings are being maintained for several river catchments in the affected area following recent heavy rainfall. Authorities will likely issue new alerts or update/rescind existing advisories 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) across parts of central and northern Texas May 28-early May 29. There is a slight risk of severe storms in surrounding areas, including much of the rest of Texas and parts of far eastern New Mexico, far southeastern Colorado, southern and western Oklahoma, far southwestern Arkansas, and central and western Louisiana.

The NWS's Weather Prediction Center has warned of a moderate risk of excessive rainfall (the second highest level on a four-tier scale) for parts of central and northern Texas and a slight risk of excessive rainfall across much of the rest of central and northern Texas and parts of southern Oklahoma.

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 or a lack of stormwater drainage systems. Sites 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 rain has saturated the soil. Disruptions to electricity and telecommunications services are possible where significant flooding, strong winds, or landslides impact utility networks.

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 could temporarily close some low-lying routes that become inundated by floodwaters. Severe weather could also trigger flight delays and cancellations at airports in the affected regions.

Localized business disruptions may occur in low-lying areas; some businesses might not operate at full capacity because of flood damage to facilities and some employees' inability to reach work sites.