Alert Details

  • Incident: Tropical Storm Delta
  • Location(s): Southern US (map)
  • Date: Early Oct. 10
  • Center of Circulation: Approximately 70 km (45 miles) south-southeast of Monroe, La., US
  • Maximum Sustained Winds: 90 knots (105 kph, 165 mph)

Summary

Critical Alert

Tropical Storm Delta weakening as it tracks northeastward over Louisiana, US, early Oct. 10, before moving over northern Mississippi.

As of early Oct. 10, Tropical Storm Delta has weakened after making landfall over Louisiana, US, Oct. 9. As of 0400 CDT Oct. 10, the system's center of circulation was approximately 70 km (45 miles) south-southeast of Monroe, Louisiana. Forecast models indicate Delta will continue to weaken as it tracks in a northeasterly direction across northeastern Louisiana during the morning of Oct. 10, before moving into northern Mississippi and the Tennessee Valley late Oct. 10 and into Oct. 11.

Delta's remnants will likely bring heavy rainfall to portions of the southern US, including Arkansas, Mississippi, Tennessee, and Kentucky, through at least Oct. 11. Some uncertainty remains in the track and intensity forecast, and changes could occur over the coming days.

Government Advisories
As of 0400 CDT Oct. 10, authorities have withdrawn all watches and warnings associated with Tropical Storm Delta. Authorities could issue new warnings throughout the system's progression in the coming days. Any new weather warnings issued could remain active even after the system's immediate threat has diminished, as some areas may still be highly susceptible to rain-induced hazards. The possibility of further localized evacuations cannot be discounted if weather conditions prove particularly hazardous.

Hazardous Conditions
Tropical Storm Delta is bringing heavy rainfall, gusty winds, and high waves to portions of the southern US, Oct. 10. Widespread rain accumulations around 5-13 cm (2-5 inches) are forecast across northern Louisiana, southeast Arkansas, and western Mississippi. Locally higher rainfall totals up to 25 cm (10 inches) are possible in areas affected by persistent bands of thunderstorms. As Delta continues to move further inland, rainfall accumulations of 2.5-7.5 cm (1-3 inches), with locally higher amounts, are possible across the Tennessee Valley and Mid-Atlantic through at least Oct. 11. There is potential for rainfall accumulations of 7.5-15 cm (3-6 inches) over the Southern Appalachians over the coming days.

Sustained heavy rainfall could trigger flooding in low-lying communities near streams, creeks, rivers, and urban areas with easily overwhelmed or a lack of stormwater drainage systems. Sites located downstream of large reservoirs could experience flash flooding after relatively short periods of intense rainfall. Flooding could isolate some communities for several days. Prolonged swells and storm surge generated by the system will likely result in coastal flooding as the system approaches the islands. A persistent onshore flow could make it difficult for the surge to recede, and water levels decrease in coastal river catchments.

The greatest impacts in terms of strong winds and storm surge will be felt just to the northeast of the center of circulation relative to the storm's track. This is partly due to the counterclockwise circulation of a hurricane in the northern hemisphere.

In addition to the heavy rain and flooding, and despite weakening, the system is likely to produce tropical-storm-force gusts in excess of 45 knots (85 kph, 50 mph) as it moves further inland. Widespread and prolonged power outages due to uprooted trees and toppled utility lines are possible; as of 0400 CT, approximately 600,000 customers in Texas, Louisiana, and Mississippi remain without power. Rain-induced landslides are also possible in hilly areas where the ground is loose and unstable, especially in areas where heavy rainfall occurred during previous tropical systems, including Hurricane Laura. Additionally, Tropical Storm Delta will likely produce tornadoes, especially in eastern Mississippi, Alabama, the Florida Panhandle, and central and western Georgia through early Oct. 11.

Transport
In addition to the immediate threat to personal safety, inclement weather associated with the storm could trigger localized business, transport, and utility disruptions over the coming days. Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel around affected areas. Areal flooding in urban locations could also result in severe traffic congestion, while strong winds will pose a hazard to high-profile vehicles. Heavy rain and low visibility may trigger flight disruptions at regional airports.

Disruptions triggered by inclement weather and resultant hazards, such as flooding, could persist well after conditions have improved. If there is severe damage to infrastructure, repair or reconstruction efforts may exacerbate residual disruptions.

Advice

Activate contingency plans in areas where officials forecast tropical storm conditions. Heed all evacuation orders. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the high potential for severe flooding and storm surge. Stockpile water, batteries, and other essentials in advance. Charge battery-powered devices when electricity is available; restrict the use of cellular phones to emergencies only. Power down mobile devices when not in use. Keep important documents in waterproof containers. Observe strict food and water precautions, as municipalities could issue boil-water advisories following flooding events. Take precautions against insect- and waterborne diseases in the coming weeks. Keep any necessary medications in a waterproof container.

Plan accordingly for protracted commercial, transport, and logistics disruptions in areas in the path of the storm, especially if vital infrastructure is damaged. Seek updated information on road conditions before driving or routing shipments through areas where flooding has occurred. Confirm flights before checking out of hotels or driving to the airport; clearing passenger backlogs may take several days in some locations.