Tropical Storm Eta, north of the Cayman Islands, is moving north-northeast toward Cuba.
"A turn toward the north and northwest at a slower forward speed is expected on Sunday and Sunday night, followed by a westward motion on Monday," said Senior Hurricane Specialist Eric Blake with the National Hurricane Center.
After it crosses the island, it is forecast to turn back to the north-northwest and approach the Florida Keys, move into the Gulf of Mexico, then turn more to the north.
"On the forecast track, the center of Eta will cross central Cuba tonight, approach south Florida and the Florida Keys on Sunday, pass near or over south Florida and the Florida Keys Sunday night and Monday and be over the southeastern Gulf of Mexico on Tuesday," said Blake.
The forecast after that becomes less certain. Long-range models show the storm slowing down as it moves north in the Gulf off the Florida peninsula.
"The track guidance becomes quite divergent," said Blake. The intensity forecast for the storm also becomes more difficult.
"Shear and dry air entrainment should prevent any further strengthening," after the next 24 to 48 hours, Blake said, although it will strengthen enough that a hurricane watch has been posted for the Florida Keys and southern peninsula.