North Atlantic: Hurricane Ernesto tracking northeastward in the North Atlantic Ocean as of Aug. 19 /update 11

Hurricane Ernesto is tracking northeastward in the North Atlantic Ocean to the southeast of Atlantic Canada Aug. 19. As of 11:00 AST, the system's center of circulation was approximately 515 km (320 miles) southeast of Halifax, Nova Scotia, Canada.

Forecast models indicate that the storm will weaken slightly but remain a Category 1 hurricane as it passes to the southeast of Newfoundland Island, Canada, late Aug. 19. The storm is then expected to weaken and transition into a post-tropical cyclone as it tracks east-northeastward further into the North Atlantic Ocean away from North America Aug. 20-21. Some uncertainty remains in the track and intensity forecast, and significant changes could occur over the coming days.

There are no coastal warnings or watches in effect as of Aug. 19. Environment Canada has issued a red rainfall warning (the highest level on a three-tier scale) for the southern Avalon Peninsula in Newfoundland and a grey tropical cyclone information statement across the Avalon, Bonavista, and Burin peninsulas. Authorities may issue new warnings throughout the system's progression in the coming days.

Swells generated by the system are affecting portions of Bermuda, the east coast of the US, and Atlantic Canada and are likely to continue through Aug. 20; these swells are likely to produce life-threatening surf and rip current conditions. Large breaking waves could possibly bring coastal flooding to parts of southeastern Newfoundland, particularly along southwest-facing shorelines from Burin east to Avalon regions.

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.

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