(Adds storm forecast to be hurricane, updates location, warnings)

MEXICO CITY, Aug 2 (Reuters) - Tropical Storm Earl bore down on Central America's Caribbean coastline late on Wednesday, strengthening as it was forecast to strike land as a hurricane, the National Hurricane Center (NHC) said.

The storm was about 350 miles (563 km) east of Belize City blowing maximum sustained winds of 60 miles per hour (97 kph), and is expected to reach the coast of Belize, famed for its coral reefs, by Thursday morning.

A hurricane warning is in effect from Puerto Costa Maya, Mexico, southward to the border between Belize and Guatemala.

A storm becomes a hurricane when its maximum sustained winds reach 74 mph (119 kph).

The NHC said in a statement the storm was first expected pass just north of the Honduras Bay Islands.

The Miami-based center said Earl "is likely to become a hurricane before it makes landfall" while dumping between 8-12 inches (20-30 cm) of rain over a wide swath of Belize, Honduras, Guatemala and Mexico's Yucatan peninsula.

"These rains could result in life-threatening flash floods and mud slides," the NHC said.

Once the storm passes over Mexico, the NHC forecasts that on Friday it will enter into the southern rim of the Gulf of Mexico where national oil company Pemex operates dozens of oil platforms.

The shallow water areas off the Gulf between the states of Veracruz and Campeche account for about three quarters of Mexico's total oil output.

Earl is the fifth named storm of the 2016 Atlantic hurricane season and formed in the northwest Caribbean on Tuesday.

(Reporting by Arpan Varghese in Bengaluru and David Alire Garcia in Mexico City; Editing by James Dalgleish, Sandra Maler and Michael Perry)