Weather, Atlantic Ocean | featured news

Tropical Storm Isaac churned away in the Atlantic Ocean early Wednesday, forecast to strengthen into a hurricane and posing a potential threat to the GOP convention in Florida next week.

With Hurricane Irene pointed at the nation's most populated city, expected to arrive by late Saturday, New York Mayor Michael Bloomberg wants coastal residents to get moving. Now. City officials made the unprecedented decision to shut down the mass transit system starting at noon Saturday and to evacuate by 5 p.m. more than 250,000 New Yorkers who live along the southern coastal rim of the city. That includes residents of Manhattan's Battery Park City, vast parts of Staten Island, Brooklyn's Howard and Manhattan beaches and everyone in the beachfront communities of Rockaway.

Dozens of flights were cancelled Sunday after an ash cloud from an erupting volcano in Chile drifted thousands of miles over the Atlantic and Indian oceans.

As Tropical Storm Igor spins across the Atlantic Ocean, forecasters say the the storm will probably strengthen and become a hurricane later Saturday.