MIAMI - Forecasters say Tropical Storm Carlotta in the Pacific is expected to become a hurricane by the time it reaches the southern coast of Mexico on Friday.
Carlotta's maximum sustained winds rose Thursday night to 65 mph (100 kph). Hurricane strength is 75 mph (120 kph).
A hurricane warning is in effect for Mexico's Pacific coast from Salina Cruz to Punta Maldonado.
The tropical storm was centred about 250 miles (400 kilometres) south-southeast of Puerto Angel, and about 460 miles (740 kilometres) southeast of Acapulco. It is moving north-northwest near 10 mph (17 kph).
Tropical storm conditions are expected by Friday afternoon and significant coastal flooding is expected. The Mexican states of Guerrero, Oaxaca and Chiapas and the southern portion of Guatemala could see up to a foot of rain.