The U.S. National Hurricane Center in Miami said Sunday night that Jova had maximum sustained winds of 100 mph.
The Category 2 storm is centered about 260 miles southwest of Manzanillo, Mexico.
It was moving east at 7 mph.
Forecasters expect Jova could become a major hurricane by Monday night or Tuesday.
A hurricane warning is out for Punta San Telmo north to Cabo Corrientes.
A tropical storm watch is in effect south of there.
Meanwhile, Tropical Storm Irwin continued swirling in the eastern Pacific, about 785 miles southwest of the southern tip of Baja California.
Irwin had maximum sustained winds of about 50 mph.
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