MEXICO CITY - Tropical Storm Hilary strengthened into a hurricane in the Pacific on Thursday and was expected to further intensify before hitting Mexico's Baja California peninsula over the weekend, forecasters said.
Heavy rainfall was also expected in the southwestern United States from Friday as the storm moves north, the US National Hurricane Center (NHC) said.
At around 1800 GMT, Hilary was packing maximum sustained winds of about 105 miles (165 kilometers) an hour, according to the NHC.
It strengthened to a Category Two hurricane -- the second lowest on a scale of five.
Hilary was located about 500 miles southeast of the tourist resort of Cabo San Lucas on the southern tip of Baja California, the NHC said.
"Additional rapid strengthening is forecast during the next day or so, and Hilary is likely to become a major hurricane," it predicted.
"Flash flooding, locally significant, will be possible," it added.
The storm brought rain and rough seas to areas along Mexico's southwestern Pacific coast, including the tourist resort of Acapulco.
In the United States, parts of southern California and southern Nevada could see heavy rain through early next week, the NHC said.
Hurricanes hit Mexico every year on both its Pacific and Atlantic coasts, usually between May and November.
dr/tjj