The latest forecast, issued at 8 a.m. EDT, predicted that Ernesto would hit South Florida as a Category 1 hurricane, with sustained winds of about 80 mph. But forecasters reminded residents that intensity is very difficult to predict and Ernesto could be stronger when it arrives.

One reliable computer model favored ''the possibility of Ernesto becoming a Category 2 or even a Category 3 hurricane before making landfall along the Florida coast,'' according to forecaster Stacy Stewart of the National Hurricane Center in West Miami-Dade County.