Tropical Storm Mario, a small cyclone, is strengthening off the west coast of Mexico Friday. It's about 20 nautical miles off the coast of Guerrero, Mexico.

Tropical Storm Mario, a small cyclone, is strengthening off the west coast of Mexico Friday. It's about 20 nautical miles off the coast of Guerrero, Mexico.

Mario, a storm system swirling off Mexico's Pacific coast, has once again become a tropical storm. There are no coastal watches or warnings in effect.

The National Hurricane Center is watching Tropical Storm Mario in the Pacific and two other potential storms.