All eyes are on the tropics, as Tropical storm Isaac could soon become a hurricane.
The storm has already brought wind and rain to Puerto Rico, and the Virgin Islands.
Forecasters say Isaac could head toward Florida as a hurricane by Monday.
And people there are starting to take precautions boarding up windows in Cape Coral on Florida's southwest coast.
Further north in tampa, workers put up rain shelters.
65,000 people are expected to travel to Tampa for the Republican National Convention, which starts Monday.