23 Mar 2022 | 06:13 AM UTC
US: Adverse weather forecast across parts of the South, Southeast, and Ohio Valley regions through at least early March 24 /update 2
Adverse weather forecast across parts of the South, Southeast, and Ohio Valley, US, through early March 24. Flooding, disruptions likely.
Event
A large weather system is forecast to bring heavy rain and thunderstorms to parts of the South, Southeast, and Ohio Valley regions through at least early March 24. The storm over Mississippi and Alabama will likely move eastwards, bringing severe weather from North Carolina to the Florida Panhandle March 23 through early March 24. Heavy downpours could trigger flooding, and the storms could spawn tornadoes and hail across parts of the affected area. Parts of the Ohio and Tennessee valleys experienced heavy rainfall over the recent weeks; river levels remain elevated. Additional rainfall over already saturated areas is likely to result in floods and flash floods.
Reports indicate at least one fatality in Arabi, St. Bernard Parish, Louisiana, due to a tornado the evening of March 22. The tornado also caused extensive damage in parts of Lower Ninth Ward in New Orleans and Arabi and trapped several people in their homes. Thousands were temporarily without power in Louisiana late March 22, but authorities have since restored services. Tornadoes have also caused damage in Choctaw County, Alabama, and West Point, Edwards, and Damascus in Mississippi.
Williamson County, Texas, declared an emergency March 21. Authorities issued a severe weather disaster declaration March 22 for Bastrop, Cass, Cooke, Grayson, Guadalupe, Houston, Jack, Madison, Marion, Montague, Nacogdoches, Panola, Rusk, Upshur, Williamson, and Wise counties in Texas due to heavy rain, large hail, damaging winds, and multiple tornadoes. Multiple tornadoes have been confirmed in parts of central and eastern Texas and Oklahoma, causing much damage. One person has died and at least 11 others injured in Northwest Grayson County late March 21. Reports indicate significant damage in Elgin, Jacksboro, Sherwood Shores, and Round Rock in Texas and Kingston, Oklahoma. Authorities estimate damage to around 60-80 houses in Jacksboro. An emergency shelter is located at First Baptist Church in Whitesboro, Grayson County. As of early March 23, more than 17,000 people remain without power across Texas, mostly in Houston and Madison counties.
Government Advisories
The National Weather Service (NWS) has issued flood and flash flood watches and warnings across Alabama and far western Florida. Tornado watches are in place across southern and central Alabama and far western Florida through early March 23. Authorities are likely to issue additional watches and warnings over the coming hours and days as the storm progresses.
The NWS's Storm Prediction Center has warned of an "Enhanced Risk" (Level 3 on a five-tier scale) for severe thunderstorms across parts of the central Gulf Coast and a "Slight Risk" over far eastern Louisiana, southeastern Mississippi, most of Alabama, and far western Florida through early March 23. A "Slight Risk" of severe thunderstorms is in effect across portions of the Southeast region and most of Ohio and northeastern Indiana from March 23 through early March 24.
The Weather Prediction Center (WPC) has issued a "Moderate Risk" for excessive rainfall over portions of eastern Mississippi and northwestern Alabama and a "Slight Risk" from far eastern Louisiana northward into far southern Indiana as well as eastwards into northwestern Georgia and the far western Florida Panhandle through early March 23. A "Slight Risk" is also in effect for portions of the Florida Panhandle and far southern Georgia through early March 24. Officials could update and possibly extend the coverage of the relevant weather alerts over the coming days.
Severe storms in the "Enhanced Risk" (Level 3) regions are forecast to be more numerous, persistent, and widespread than those in the region where a "Slight Risk" (Level 2) is in effect. Storms in the Slight Risk regions are not forecast to be widespread or long-lived. Isolated intense storms are possible; however, widespread damage is unlikely. Isolated intense storms are possible, containing hail, damaging winds, and a few tornadoes.
Hazardous Conditions
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 possible where significant flooding or landslides impact utility networks.
Transport
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 region, including but not limited to Louis Armstrong New Orleans International (MSY), Memphis International (MEM), and Nashville International (BNA) airports. Authorities canceled hundreds of flights at Dallas/Fort Worth International (DFW) and Dallas Love Field (DAL) airports and around 90 flights at Austin-Bergstrom International Airport (AUS) March 21; most flights have since resumed, but lingering disruptions are likely. 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 may occur in low-lying areas; some businesses might not operate at full capacity because of flood 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.
