Hurricane Norbert strengthened into a Category 4 storm over the Pacific Ocean on Wednesday and is expected to reach Mexico's Baja California peninsula by the weekend. (National Oceanic and Atmosphere Administration/Associated Press)

Hurricane Norbert continued to gain strength on Wednesday as it moved across the Pacific Ocean toward Mexico.

Norbert, now a Category 4 storm, is forecast to hit Mexico's Baja California peninsula by the weekend.

On Wednesday afternoon, the hurricane was about 715 kilometres south of the southern tip of Baja California, moving west-northwest at about 15 kilometres per hour.

Norbert is the seventh hurricane of the East Pacific season.

Officials at the U.S. National Hurricane Center warned area residents that they should continue to monitor the progress of Norbert for the next 48 hours.

Norbert is expected to turn northeast Thursday before continuing on a northerly route on a path that could take it over the southern Baja peninsula and the Mexican mainland, according to the hurricane centre. It is expected to make landfall north of the city of La Paz.

As of 2 p.m. ET Wednesday, Norbert's maximum sustained winds were near 215 km/h. The hurricane centre said the storm strength is expected to fluctuate over the next 24 hours and then weaken by Friday.

Tropical storm Marco dissipates

Meanwhile, Marco, another storm system in Mexico's Gulf coast, has weakened into a tropical depression.

Tropical storm Marco made land fall about 90 km north of the port city of Veracruz on Tuesday with near hurricane-force winds.

Mexico's state oil company shut down some of its oil platforms in the gulf and evacuated about 3,000 people from area towns before Marco hit the coast.

State authorities closed schools in the state of Veracruz, evacuated a hospital in the north and set up 200 shelters as the storm flooded coastal highways.

Military and rescue officials were busing people from low-lying communities in the state, where storms last week had already left rivers swollen. Some towns were already under more than three metres of water before Marco hit.

But the Associated Press reported that much of the water-logged areas in southern Veracruz were spared from Marco.

The storm dissipated over Mexico's mountainous terrain on Tuesday night.

With files from the Associated Press and Reuters