US: Adverse weather forecast to continue across southern and central regions through at least early May 24 /update 1

Severe weather is forecast to continue across parts of the southern and central US through at least early May 24. Thunderstorms, heavy rainfall, and strong winds are forecast from the central plains across the upper Mid-West to the Great Lakes May 21-22. Another system is expected to bring severe weather from the southern plains across the mid-Mississippi Valley and into the Ohio Valley May 22-23. 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 May 21, the National Weather Service (NWS) has issued severe thunderstorm warnings for parts of central Iowa and severe thunderstorm watches over much of the rest of Iowa. Flash flood warnings are in place for parts of eastern Nebraska and western and central Iowa. Flood warnings, watches, and advisories have been issued across parts of eastern and southern Nebraska, northern and western Iowa, central, eastern, northeastern, and southern Minnesota, and northwestern Wisconsin. Wind advisories are in place for parts of western Minnesota, northwestern Iowa, southeastern Missouri, southern Illinois, southwestern Indiana, and western Kentucky. Authorities will likely issue new alerts or update/rescind existing advisories over the coming days.

The NWS's Storm Prediction Center has warned of a moderate risk of severe thunderstorms (the second highest level on a five-tier scale) across much of Iowa and parts of northern Missouri, far southeastern Minnesota, southwestern Wisconsin, and northwestern and western Illinois May 21-early May 22. There is an enhanced risk of severe storms for surrounding areas of eastern Nebraska, northwestern Iowa, far eastern Kansas, central, northern, and western Missouri, central, northern, and western Illinois, far northwestern Indiana, western Michigan, central and southern Wisconsin, and southeastern Minnesota. There is a slight risk of severe storms for a wide area from central Texas northeastward to the Upper Peninsula of Michigan. There is a further enhanced risk of severe storms for parts of northeastern Texas, southeastern Oklahoma, central and northern Arkansas, southern Missouri, and far northwestern Tennesee and a slight risk for surrounding areas from central Texas northeastward to the Ohio Valley and extending into western Pennsylvania, and western New York May 22-early May 23. There is a slight risk of severe storms for parts of northeastern Texas, central and eastern Oklahoma. central and southern Nebraska, southwestern Missouri, central and western Arkansas, and far northwestern Louisiana May 23-early May 24.

The NWS's Weather Prediction Center has warned of a slight risk of excessive rainfall (the second lowest level on a four-tier scale) across much of Minnesota and parts of far northeastern South Dakota, east-central and northern Iowa, and western and west-central Wisconsin May 21-early May 22. There is a further slight risk of excessive rainfall for parts of northeastern Texas, southeastern Oklahoma, central and northern Arkansas, southern Missouri, far southwestern Kentucky, and northwestern Tennessee May 22-early May 23 and for parts of northeastern Texas, southeastern Oklahoma, central Arkansas, far southwestern Tennessee, and far northwestern Mississippi May 23-early May 24.

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.