(CNN) -- Tropical Storm Gert is gaining strength as it barrels toward the Atlantic island of Bermuda, the National Hurricane Center said Sunday.
The storm system was about 255 miles south-southeast of Bermuda and "slowly strengthening" as it heads north, according to a 5 p.m. advisory from the center, which is part of the National Weather Service.
Equipment aboard U.S. Air Force aircraft recorded maximum sustained winds of 45 mph, with stronger gusts reported.
Gert's eye is forecast to go near or just east of Bermuda on Monday afternoon, prompting a tropical storm warning for the island. No other islands are similarly threatened, and the storm is expected to eventually turn northeast back out over open sea.
The hurricane center predicts large swells that "are likely to cause life-threatening surf and rip current conditions" could affect Bermuda as soon as Sunday night. Between 1 to 3 inches of rain is expected to fall on the island, as a result of the storm.
Gert is the seventh named storm of the 2011 Atlantic hurricane season.