MIAMI -- Tropical Storm Blanca has formed in the Pacific Ocean off Mexico and is expected to strengthen quickly over the next two days.

The second named storm of the season was centred about 540 kilometres south-southwest of Zihuatanejo, Mexico, on Monday. It has maximum sustained winds of 65 kph and is moving northwest at 7 kph.

The U.S. National Hurricane Center in Miami says no coastal warnings or watches are in effect, but the storm is expected to gain strength and become a hurricane Tuesday. Forecasters call it a slow-moving storm.

Meanwhile, Hurricane Andres weakened a bit Monday morning. It is about 1,350 kilometres southwest of the southern tip of Baja California. It is moving west-northwest at 9 kph with maximum sustained winds of 220 kph. No warnings or watches are in effect.