Tropical Storm Beatriz, the second named storm of the Pacific hurricane season, gathered strength off Mexico's Pacific Coast on Sunday, the U.S. National Hurricane Center said.
A hurricane warning was in effect for the Mexican coast from Zihuatanejo westward to Manzanillo, and a watch was in effect from Manzanillo westward to La Fortuna, the National Hurricane Center said in its 11 p.m. PDT (0600 GMT on Monday) report.
The center of Beatriz was expected to approach the coast within the hurricane warning area by late Monday or early Tuesday, the center said.
Beatriz was 160 miles southwest of Zihuatanejo and headed west-northwest at 12 mph (19 kph) with maximum sustained winds of near 55 mph.
Mexico has no oil installations in the Pacific but its coast is dotted with beach resorts popular with U.S. tourists.