Tropical Storm Ian was forecast to rapidly gain strength Sunday while racing across the Caribbean toward Cuba and threatening a big hit to Florida's west coast later in the week. Ian was forecast to reach hurricane status Sunday, then roll across western Cuba Monday night and early Tuesday. "Significant" wind and storm surge damage was expected, and the Cuban government upgraded the hurricane watch to warning. Ian was then forecast to head for the southeastern Gulf of Mexico, the National Weather Service said. "Ian is expected to become a hurricane later today or tonight and reach major hurricane strength by late Monday or Monday night before it reaches western Cuba," warned Brad Reinhart, a hurricane specialist at the National Hurricane Center. Major hurricanes rate Category 3 or higher on a scale of 1-5, with sustained winds of more than 110 mph. Such storms can cause "devastating" damage. Follow the link in our bio for the latest updates on Ian. Photo: @noaa via AP