MEXICO CITY (AP) — Tropical Storm Roslyn gained strength off Mexico’s Pacific coast on Friday and forecasters expected it to be a hurricane when it makes a likely weekend landfall between the resorts of Puerto Vallarta and Mazatlan.

The U.S. National Hurricane Center said Roslyn’s maximum sustained winds had increased to 65 mph (100 kph) Friday. It was centered about 290 miles (465 kilometers) south-southeast of Cabo Corrientes — the point of land jutting into the Pacific south of Puerto Vallarta — and moving west-northwest at 7 mph (11 kph).

Forecasters said Roslyn was expected to continue gaining force and could be a strong Category 2 hurricane before curving northward, brushing past Cabo Corrientes and then reaching the coast Saturday night or Sunday.

The hurricane center said tropical storm-force winds extended out to 90 miles (150 kilometers) from Roslyn’s core.

Mexico issued a hurricane warning covering the Bahia de Banderas that includes Puerto Vallarta and for a strip of coast to the south of the bay.

The National Water Commission said rains from Roslyn could cause mudslides and flooding. and the U.S. Hurricane Center warned of dangerous storm surge along the coast.