The first hurricane of the 2010 season had maximum sustained winds of about 75 mph (120 kph) and was expected to gradually strengthen.
The storm was moving westward at about 7 mph (11 kph). That course would take Celia into the open Pacific, and forecasters said there was no immediate threat to land.
Dario Rodriguez, a forecaster at Mexico's National Meteorological Service, said Mexico would not be affected by wind or rain from Celia because it was too far out to sea.
Elsewhere, Blas weakened from a tropical storm to tropical depression, with maximum winds of 35 mph (55 kph).
That storm was centered far out to sea — 470 miles (755 kilometers) southwest of the southern tip of Mexico's Baja California peninsula — and was moving west-northwest at about 13 mph (20 kph).