US: Adverse weather forecast across east-central regions through at least July 29

Event

Rounds of heavy rainfall accompanied by possible thunderstorms are forecast across parts of the east-central US through at least July 29. Heavy downpours are expected from the mid-Mississippi Valley to the Ohio Valley and the central Appalachians over the coming days. Sustained heavy rainfall may result in floods and flash floods, especially over low-lying areas or areas close to water bodies.

There have been multiple reports of flooding across parts of Saint Louis and surrounding areas early July 26. A flash flood emergency is in effect for Creve Coeur, Frontenac, Ladue, University City, and Maryland Heights and a flash flood warning has been issued for central Saint Louis and the Saint Louis City area through 09:30 CDT. Some areas have received 15-25 cm (6-10 inches) of rainfall early July 26 and further rainfall is forecast in the coming hours. Residents are being advised to seek higher ground due to the threat of flash flooding, especially those in the emergency warning areas. Several roads in the areas have been inundated by floodwaters, including sections of Interstate 44 and 70. Vehicles have been submerged on flooded streets across the city, including N Skinner Parkway, Scheutz Road, and Adie Road. Response and rescue operations are ongoing.

Government Advisories
As of July 26, the National Weather Service (NWS) has issued flash flood warnings across parts of eastern Missouri and southern and western Illinois. Flood warnings have been issued for parts of southeastern Illinois and far southwestern Indiana. Flood watches have been issued for parts of eastern Missouri, southern and central Illinois, and southwestern Indiana.

The Weather Prediction Center (WPC) has issued a "Slight Risk" (Level 2 on a four-tier scale) for parts of far eastern Missouri, southern Indiana, much of Kentucky, southern Ohio, southern and central West Virginia, far western Virginia, and far northeastern Tennessee July 26-27. There is a "Moderate Risk" (Level 3) of excessive rainfall for much of West Virginia and far eastern Kentucky July 27-28, as well as a "Slight Risk" for parts of southeastern Missouri, southern Illinois, southern Indiana, Kentucky, northern Tennessee, the rest of West Virginia, western Virginia, and southwestern Pennsylvania. Similar Moderate and Slight risk warnings areas are in place July 28-29, with the Slight warning area extending slightly further westward into northern Arkansas and southern Missouri, as well as slightly further southwards across much of Tennessee.

Officials could update and possibly extend the coverage of weather alerts over the coming days.

Hazardous Conditions
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 and tornado warnings advising the public to shelter in place. Disruptions to electricity and telecommunications services are possible where severe weather impacts utility networks.

Transport
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 could temporarily close some low-lying routes that become inundated by floodwaters.

Severe weather could also trigger flight delays and cancellations at airports across the affected region. Flooding could block regional rail lines; freight and passenger train delays and cancellations are likely in areas that see heavy rainfall and potential track inundation.

Localized business disruptions may 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.

Advice

Monitor local media for weather updates and related advisories. Confirm all transport reservations and business appointments before travel. Make allowances for localized travel delays and potential supply chain disruptions where flooding has been forecast. Do not drive on flooded roads. Review contingency plans and be prepared to move quickly to shelter if tornado warnings are issued. Charge battery-powered devices in the case of prolonged electricity outages.

Resources

National Weather Service