MIAMI – Two tropical storms gathered strength off Mexico’s Pacific coast Monday, with one forecast to become a hurricane later in the day, forecasters warned.

Tropical Storm Barbara was about 185 miles (295 kilometers) southwest of Manzanillo, Mexico early on Monday, with maximum sustained winds of 70 mph (110 kph), according to the U.S. National Hurricane Center in Miami.

Barbara is expected to continue moving toward the west-northwest near 12 mph for the next couple of days. It will reach hurricane strength later on Monday but should begin weakening by Tuesday, the NHC said.

The storm may bring total rainfall of 2 to 4 inches (51 to 101 millimeters) to coastal areas of Guerrero, Michoacan, Colima and Jalisco states, with the possibility of localized flooding on Monday.

The NHC said swells from Barbara were likely to form life-threatening surf and rip current conditions along the southwestern Mexican coast, with gusty winds likely.

Another tropical storm, Cosme, strengthened slightly Monday but remained well off the coast of Mexico, about 630 miles (1,015 kilometers) south-southwest of the tip of Baja California, the NHC said.

At 2 a.m. local time it had maximum sustained winds of 50 mph and was moving west-northwest at 9 mph. Cosme is expected to reach near-hurricane strength on Monday before turning to the northeast and picking up speed Tuesday into Wednesday.