North Atlantic: Post-Tropical Cyclone Lee approaching Atlantic Canada as of Sept. 16 /update 11

Event

Hurricane Lee has transitioned into a post-tropical cyclone and is tracking northward in the North Atlantic Ocean just off the southwestern coast of Nova Scotia, Canada, Sept. 16. As of 11:00 AST, the system's center of circulation was approximately 240 km (150 miles) west-southwest of Halifax, Nova Scotia.

Forecast models indicate that the storm will make landfall over southwestern Nova Scotia during the afternoon of Sept. 16. The post-tropical system is then forecast to pass over southern New Brunswick before turning to track northeastward and entering the Gulf of St. Lawrence late Sept. 16. The system will likely pass over far northern Newfoundland late Sept. 17 before entering the Labrador Sea. Some uncertainty remains in the track and intensity forecast, and changes could occur over the coming days.

As of Sept. 16, officials have issued the following coastal watches and warnings:

• Hurricane Watch: New Brunswick from the US-Canada border to Point Lepreau, including Grand Manan Island; Nova Scotia from Digby to Ecum Secum.

• Tropical Storm Warning: Portsmouth, New Hampshire, to the US-Canada border; New Brunswick from the US-Canada border to Belledune, including Grand Manan Island; all of Nova Scotia; Prince Edward Island; Magdalen Islands.

Authorities will likely issue new warnings throughout the system's progression in the coming hours and days.

Hurricane conditions are possible in the hurricane watch areas in Atlantic Canada later Sept. 16. Tropical storm conditions are occurring along the coasts of New England and Nova Scotia and will likely spread through the rest of the tropical storm warning area through Sept. 16. The system is forecast to produce rainfall totals of 2.5-10 cm (1-4 inches) across parts of far eastern Massachusetts and eastern Maine in the US and parts of New Brunswick and western Nova Scotia in Atlantic Canada through Sept. 16.

Water levels reportedly remain elevated along the coast of New England as of Sept. 16 and will likely start to decrease following the next high tide cycle. Storm surge is forecast to produce coastal flooding along parts of the Atlantic Canada coast within the wind warning areas. Swells generated by Lee are affecting portions of the US Virgin Islands, Puerto Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas, Bermuda, the east coast of the US, and Atlantic Canada; these swells are likely to produce life-threatening surf and rip current conditions.

Power outages have already been reported in parts of Atlantic Canada ahead of Lee's landfall. As of Sept. 16, authorities have reported more than 120,000 customers without power in Nova Scotia as well as more than 40,000 in New Brunswick. Numerous flights and ferry services have been canceled in the Maritimes. Flights have also been canceled across parts of the northeastern US, including over 100 flights at Boston Logan International Airport (BOS). Maine Governor Janet Mills declared a state of emergency Sept. 14 ahead of the arrival of the storm.

Sustained heavy rainfall could trigger flooding in low-lying areas and those with easily overwhelmed drainage systems. If weather conditions prove hazardous, localized evacuations, flash flooding, and landslides are possible.

The inclement weather could trigger localized business, transport, and utility disruptions and render some bridges or roadways impassable. Flight disruptions at regional airports and temporary closures of ports are also possible. Stagnant pools of water during and after flooding may increase the incidence of insect- and waterborne diseases. Exposure to raw sewage and other hazardous materials mixed with floodwaters poses a serious health threat.

Advice

Activate contingency plans in areas where officials forecast tropical storm conditions. Heed any evacuation orders that may be issued. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the 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 weeks.

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