After drenching Bermuda, parts of the Virgin Islands and Puerto Rico in the middle of the week, forecasters said Philippe, now a post-tropical cyclone, would likely bring heavy rains and high winds to New England this weekend.
The heavy rain is expected to begin late on Friday night and could also cause flash flooding in northern New York State, northern Pennsylvania and New England, said Bob Oravec, a lead forecaster at the Weather Prediction Center in College Park, Md.
“Some of the heaviest rain looks like it’s going to be during the day on Saturday, especially for northern New York and western portions of New England, and then by Saturday evening for coastal sections of New England,” Mr. Oravec said.
He added that the hilly terrain in New England was especially vulnerable to flash flooding.
On the coast from eastern Massachusetts to Maine, there will likely be high, gusty winds, Mr. Oravec said. These wet and windy conditions could also affect Atlantic Canada, including Nova Scotia and New Brunswick.
The strongest winds are expected over Nova Scotia. While Canadian forecasters warn it is too early to know where the most powerful winds will be, there is a 10 percent chance those winds could strengthen to hurricane-force, which is 74 miles per hour or higher.
Once a tropical storm, Philippe will be a post-tropical cyclone when it reaches the coast of New England or Atlantic Canada, according to the National Hurricane Center.
Tropical systems like hurricanes acquire their energy from warm ocean temperatures, while typical storm systems in the United States get their energy from competing masses of cooler and warmer air. A storm that has transitioned to post-tropical has become a more typical storm system with warm and cold fronts.
This process typically weakens a storm while expanding how far its damaging winds can stretch.
Philippe is similar to Lee, which caused tropical storm conditions along Nova Scotia and coastal Massachusetts last month. Both storms started off as tropical storms in the western Atlantic before heading North.
Judson Jones contributed reporting.