US: Adverse weather forecast across southern regions through at least early June 21

Severe weather is forecast across parts of the southern US through at least early June 21. Moisture over the region associated with a tropical rainstorm in the Gulf of Mexico is expected to generate showers and storms initially over central Gulf Coast regions June 17-18 before the worst of the weather shifts westward into parts of Texas June 18-20. Sustained heavy downpours may trigger flooding in low-lying areas across parts of the region over the coming days.

As of June 17, the National Weather Service (NWS) is maintaining flood warnings for some river catchments in eastern Texas and coastal flood watches and advisories are in place for parts of the Central Gulf coastline. 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 coastal and adjacent inland areas of southeastern Texas, southern Louisiana, southern Mississippi, and far southwestern Alabama through early June 18. There is a moderate risk of excessive rainfall for parts of southeastern Texas, including Houston, and far southwestern Louisiana June 18-19 and a slight risk for surrounding areas. There is a further moderate risk for parts of southern Texas around San Antonio and Houston and a slight risk across much of the rest of southern and central Texas June 19-20. There is a further slight risk of excessive rainfall for areas of southern Texas to the west of San Antonio June 20-21. Authorities will likely issue new alerts or update/rescind existing advisories over the coming days.

Sustained heavy rainfall could trigger further flooding, especially 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.