17 Aug 2021 | 11:56 PM UTC
US: Tropical Depression Fred tracking north-northeastward over northern Georgia Aug. 17 /update 15
TD Fred tracking north-northeastward over northern Georgia, US, Aug. 17; system forecast to track over Appalachian Mountains Aug. 18.
Event
Tropical Depression Fred is tracking north-northeastward over northern Georgia Aug. 17. As of 17:00 EDT Aug. 17, the storm's center of circulation was approximately 140 km (90 miles) west-southwest of Asheville, North Carolina. Forecast models indicate the system will maintain its current strength despite transitioning to a post-tropical cyclone by early Aug. 18, and will track across the Appalachian Mountains through Aug. 18. The post-tropical system will then turn further northeastward and track across parts of Pennsylvania, New York, and Massachusetts Aug. 19 before ultimately entering the Gulf of Maine by early Aug. 20. Some uncertainty remains in the track and intensity forecast, and significant changes could occur in the coming days.
Government Advisories
As of 16:00 EDT Aug. 17, the Storm Prediction Center (SPC) had issued an "Enhanced Risk" advisory (third-highest level on a five-tier scale) for severe weather for parts of North Carolina and South Carolina, including the cities of Charlotte, Winston-Salem, and Gastonia, effective through early Aug. 18.
Additionally, flood watches are in place for northern Georgia, eastern Kentucky, western North Carolina, western South Carolina, eastern Tennessee, southeastern Ohio, West Virginia, southwestern and northern Virginia, Washington, DC, and parts of Maryland, Pennsylvania, and New York. Tornado watches are in place for parts of South Carolina, western North Carolina, and southwestern Virginia.
Officials could issue new warnings and/or watches in response to the system in the coming hours.
Hazardous Conditions
The storm will likely bring heavy rainfall and strong gusts to parts of the Appalachian Mountains and the Northeast region over the coming days. Sustained heavy rainfall could trigger flooding in low-lying communities near streams, creeks, rivers, and urban areas with easily overwhelmed stormwater drainage systems. Sites located downstream of large reservoirs could experience flash flooding after relatively short periods of intense rainfall. Forecast models indicate the system will likely bring 2.5-7.5 cm (1-3 inches) of additional rainfall to the Southern Appalachians and 5-10 cm (2-4 inches) of additional rainfall across the Central Appalachians, the interior parts of the Mid-Atlantic states, and parts of the Northeast. Torrential precipitation could trigger flash floods and mudslides.
In addition to the heavy rain and flooding, the storm could produce damaging wind gusts, resulting in power outages due to fallen trees and toppled utility lines. Tornadoes are possible across parts of Georgia, the western Carolinas, and southwestern Virginia until early Aug. 18.
Transport
In addition to the immediate threat to personal safety, inclement weather associated with the storm could trigger localized business, transport, and utility disruptions in areas impacted by the system. Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and 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 weather 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 adverse conditions. Heed all evacuation orders. Use extreme caution in low-lying areas and near streams, creeks, and other waterways due to the high potential for severe flooding. 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 and necessary medications 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 days.
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.
