MIAMI - The lower and middle Florida Keys are under a tropical storm warning as Hurricane Rafael is forecast to grow steadily on a path for Cuba, where it's expected to arrive on Wednesday. A tropical storm warning is also issued for portions of Cuba. A hurricane warning is in effect for parts of Cuba.

Forecast models suggest steady to rapid strengthening, with a nearly 40% chance of a 35 mph increase in wind speed within the next 24 hours. However, as it nears the central Gulf later this week, increased wind shear, drier air, and slightly cooler waters are likely to weaken it.