MEXICO CITY -- Hurricane Bud grew to Category 3 force off Mexico's Pacific coast Monday, though forecasters said it was likely to weaken before a possible brush with the resort-dotted southern tip of the Baja California peninsula late in the week.

The U.S. National Hurricane Center said Bud had maximum sustained winds of 120 mph (195 kph) at midafternoon Monday. It was centred about 440 miles (705 kilometres) south-southeast of the tip of the Baja peninsula and was moving northwest at 7 mph (11 kph).

Forecasters said the storm could strengthen a bit more before a slow weakening trend started Tuesday.

"Significantly cooler waters around the southern tip of Baja California should reduce Bud's intensity below hurricane status before it reaches that land," the centre said.

The centre said the hurricane's core was moving farther from Mexico's southwestern coast but still could generate dangerous heavy surf and rip currents over the coming days. Rainfall of 3 to 6 inches (75 to 150 millimeters), with isolated patches of 10 inches (250 millimeters), was possible over much of that region into Tuesday afternoon.

Meanwhile, Tropical Storm Aletta weakened into remnant low-pressure system in the Pacific, far from the Mexican coast. The storm peaked on Friday as a Category 4 hurricane with winds of 140 mph (220 kph).