More than 40 million people in the northeastern United States braced Friday for heavy rain and strong winds as an unusually powerful storm for the season was forecast to crash into the region. 

New York, Boston and Philadelphia were all in the firing line of the "Nor'easter" -- so labeled for its northeasterly winds -- as authorities warned of potential flooding, downed trees and damaged power lines. 

British pop singer Ed Sheeran's weekend concerts near Boston were canceled due to the looming storm, which could whip up gusts of over 60 mph (100 kmh) along the east coast. |

The Federal Aviation Administration told airplane passengers to check its website for travel updates, telling AFP there is "always a chance for restrictions depending on the weather."

Three major airlines -- JetBlue, United and American -- issued travel alerts allowing passengers to change their flights without incurring fees. 

In New York, Mayor Zohran Mamdani urged residents to "look out for your neighbors" after updated forecasts showed the storm shifting closer to the city than first predicted. 

"If you're traveling this weekend, give yourself extra time. Check your train, ferry, or flight before you leave, and avoid low-lying coastal roads around high tide," Mamdani said on X.  

Up to 13 centimeters (about 5 inches) of rain was forecast in areas of Massachusetts including Boston -- the equivalent of more than a month's worth of rainfall.

"Strong Nor'easter off the mid-Atlantic and northeast will bring coastal flooding, rip currents, strong wind gusts, and heavy rain to the region this weekend," the National Weather Service said on its website.

Some coastal areas of North Carolina, Virginia, Maryland, Delaware and New Jersey have already seen flooding this week. 

Nor'easters can occur throughout the year but are more frequent between fall and early spring. They are almost always accompanied by heavy rain or snowfall, as well as strong wind gusts. 

Earlier this year, a Nor'easter that pummeled the northeast disrupted hundreds of flights and left thousands of homes and businesses without power. 

That storm came weeks after the region recovered from another devastating winter weather system that was linked to more than 100 deaths.