Tropical Storm Celia churned through the Pacific Ocean off southern Mexico on Sunday as U.S. forecasters warned the storm could become a hurricane later in the day.

Large ocean swells from Celia were producing dangerous surf along portions of Mexico’s Pacific coast, and the storm is expected to get stronger in the next few hours, the U.S. National Hurricane Centre in Miami warned.

At 5 a.m. EDT (0900 GMT), Celia was centred 340 miles (550 kilometres) south-southeast of the Mexican resort city of Acapulco, the centre said. Maximum sustained winds were about 65 mph (100 kph) and the storm was moving westward at 8 mph (13 kph).

Hurricanes have winds of at least 74 mph (119 kph).

Also Sunday, Tropical Storm Blas in the Pacific Ocean continued to weaken as its maximum winds dropped to 45 mph (75 kph), down from about 60 mph (95 kph) late Saturday night. The centre said Blas would further weaken through Monday.

Blas was centred 405 miles (650 kilometres) south-southwest of the southern tip of Mexico’s Baja California peninsula and was moving west-northwest at 9 mph (15 kph).

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