US, Canada: Post-tropical Storm Elsa tracking northeastward in Gulf of Maine late July 9 /update 17

Event

Post-tropical Storm Elsa is tracking northeastward in the Gulf of Maine late July 9. As of 23:00 EDT, the storm's center of circulation was approximately 180 km (112 miles) southwest of Saint John, New Brunswick, Canada. Forecast models indicate the system will gradually weaken as it continues northeastward toward New Brunswick through early July 10; landfall will likely occur near Saint John. Elsa will enter the Gulf of Saint Lawrence before making another landfall over northwestern Newfoundland later the same day. The system is forecast to dissipate over the North Atlantic Ocean by early July 11. Some uncertainty remains in the track and intensity forecast, and changes could occur in the coming days.

Government Advisories
As of 23:00 EDT July 9, US authorities have lifted all tropical storm-related warnings for the northeastern US.

As of 22:00 AST July 9, Canadian officials are maintaining heavy rainfall warnings for New Brunswick, parts of northwestern Nova Scotia, and northwestern Newfoundland.

Officials could issue new warnings and/or watches in response to the developing system in the coming hours and days.

Hazardous Conditions
Elsa will continue to bring moderate-to-heavy rainfall, strong winds, and rough seas to northeastern US and eastern Canada through at least July 11. 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 rainfall totals of up to 5 cm (2 inches) for northeastern Maine in the coming hours. Around 5-8 cm (2-3 inches) of rainfall are also likely for New Brunswick and parts of Nova Scotia and Newfoundland, with up to 10 cm (4 inches) locally, through July 10. The forecast rainfall could trigger flash flooding and mudslides, potentially isolating some communities for several days. In addition to the heavy rain, flooding, and storm surge, Elsa 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 across the northeastern US and far eastern Canada through at least July 11. 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 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 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.

Resources

US National Hurricane Center
National Weather Service
Meteorological Service of Canada