Hurricane Ivo slowed its forward motion Thursday as it began to curve toward Mexico's Pacific coast, the National Hurricane Center said.

The storm, which was upgraded late Wednesday to a Category 1 hurricane, had sustained winds of about 75 mph, with gusts of 90 mph. It was moving to the north-northwest at about 7 mph, down from 13 mph on a west-northwest track Wednesday night.

Click here to track Hurricane Ivo.

At 5 a.m. EDT, it was centered roughly 520 miles south-southwest of Cabo San Lucas at the tip of the Baja California peninsula. It was forecast to take a clockwise turn toward the Baja.

The Miami-based Hurricane Center said that Ivo was likely to strengthen through midday Thursday and then weaken into a tropical storm before hitting land Sunday. But it warned that the intensity forecast for the weekend "is highly uncertain" and urged people in the peninsula to closely monitor Ivo.