North Atlantic Ocean: Tropical Storm Peter tracking west-northwestwards in the southern North Atlantic Ocean Sept. 20 /update 1

Event

Tropical Storm Peter is tracking west-northwestwards in the southern North Atlantic Ocean Sept. 20. As of 23:00 AST, the storm's center of circulation was approximately 180 km (110 miles) north of the northern Leeward Islands. Forecast models indicate the system will weaken slightly while tracking west-northwestward adjacent to the northern coasts of the northern Leeward Islands and Puerto Rico through Sept. 21. Peter is forecast to make a slow turn to track northeast as it weakens into a tropical depression through late Sept. 23. The system is likely to continue tracking northeast while weakening slightly, eventually dissipating south of Bermuda late Sept. 25. Some uncertainty remains in the track and intensity forecast, and significant changes could occur in the coming days.

Government Advisories
As of late Sept. 20, no watches or warnings are in effect. Officials could issue new warnings and/or watches in response to the developing system in the coming days.

Hazardous Conditions
The system will likely bring heavy rainfall, strong winds, and rough seas to coastal areas in the northern Leeward Islands, Virgin Islands, and Puerto Rico through at least Sept. 21. 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 2.5-7.5 cm (1-3 inches) of rainfall are likely across portions of the northern Leeward Islands, including the Virgin Islands, as well as Puerto Rico and northern Hispaniola through Sept. 21. Flooding could trigger flash floods and mudslides, isolating some communities for several days.

Prolonged sea swells and storm surge generated by the system may result in coastal flooding. Persistent onshore flow could make it difficult for the surge to recede and for water levels to decrease in coastal river catchments. In addition to the heavy rain, flooding, and storm surge, Peter could produce damaging wind gusts, resulting in power outages due to fallen trees and toppled utility lines.

Transport
In addition to the immediate threat to personal safety, inclement weather associated with the storm could trigger localized business, transport, and utility disruptions. 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 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 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 days. 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.

Resources

US National Hurricane Center
National Weather Service
Dominican Republic Oficina Nacional de Meteorologia (Spanish)
Meteo-France (French)