Tropical Storm Roslyn is forming off the coast of Mexico and could intensify into a hurricane

Newly formed Tropical Storm Roslyn was gaining strength off Mexico’s southern Pacific coast, and forecasters were expecting it to be a hurricane when it was likely to make landfall between the resort towns of Puerto Vallarta and Mazatlan over the weekend.

The US National Hurricane Center said Roslyn’s maximum sustained winds rose to 50 miles per hour late Thursday night. It was centered about 230 miles south-southeast of Manzanillo and moving northwest at 8 miles per hour.

Forecasters said Roslyn is expected to reach hurricane strength by Friday night. They said it would gradually switch to a more northerly course and begin moving towards land in the coming days.

The hurricane center said tropical storm winds extended as far as 60 miles from Roslyn’s core.

Mexico issued a tropical storm warning from Manzanillo to Cabo Corrientes, which is near Puerto Vallarta. The National Water Commission said rain from Roslyn could cause mudslides and flooding.