Tropical Storm Wilma has been upgraded to a Category One hurricane.
The US National Hurricane Centre said Wilma may affect the Yucatan Peninsula of southern Mexico before moving on to Cuba and southern Florida.
The centre said Wilma was expected to dump up to 15 centimeters of rain over the Cayman Islands, Jamaica, Haiti and southeastern Cuba.
Wilma is a record-equalling 21st storm of the Atlantic season; the record was set in 1933.
Oil experts fear that Wilma could strike oil and gas facilities in the Gulf of Mexico, which were already damaged by Hurricanes Rita and Katrina.
