Screenshot of Tropical Storm Cosme in the eastern Pacific ocean southwest of Mexico on Monday, June 24, 2013, from the National Hurricane Center website.

Screenshot of Tropical Storm Cosme in the eastern Pacific Ocean southwest of Mexico on Monday, June 24, 2013, from the National Hurricane Center website. (© NOAA/ National Weather Service)

MIAMI (AP) — Tropical Storm Cosme is strengthening in Pacific waters southwest of the Mexican mainland and forecasters say it's expected to become a hurricane within a day.

The storm's maximum sustained winds Monday afternoon have risen to 60 mph (95 kph). The U.S. National Hurricane Center in Miami says more strengthening is expected in the coming 48 hours with Cosme expected to become a hurricane sometime Tuesday.

Cosme is centered about 335 miles (535 kilometers) southwest of Manzanillo, Mexico, and is moving northwest at 14 mph (22 kph).

No coastal watches or warnings are in effect.

The hurricane center says ocean swells generated by the storm will begin affecting a swath of the Pacific coast from Manzanillo to Cabo Corrientes later Monday night with life-threatening surf and rip currents possible.

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