Tropical Storm Gert, the seventh such storm of the season, has formed in the Atlantic and could approach Bermuda by late Sunday, US forecasters said.At 1800 GMT, Gert was about 275 miles (443 kilometers) southeast of Bermuda, according to the Miami-based National Hurricane Center.It had maximum sustained winds of 40 miles (64 kilometers) per hour and was moving toward the northwest at seven miles (11 kilometers) per hour.According to the NHC, Gert will approach Bermuda late Sunday or early Monday, prompting the government there to issue a tropical storm warning.\"Additional strengthening is forecast during the next 48 hours,\" the NHC warned.