Tropical Storm Andres was expected to grow into the Pacific season’s first hurricane today and deal a glancing blow to southwestern Mexico before churning its way up the coast past picturesque towns popular with foreign retirees.

Mexico issued a hurricane warning for the Pacific coast from just south of Manzanillo north to near Puerto Vallarta. To the south, officials in Acapulco prepared 120 shelters and warned residents to stay indoors, especially some 15,000 people in zones most at risk for flooding. Heavy rains late Sunday knocked down a few trees in the resort city.

Forecasters said Andres was likely to brush the coast at hurricane strength around the port city of Manzanillo today. Forecast models showed its center later pushing up the coast near towns such as Barra de Navidad that are home to some American and Canadian expatriates.

At Barra de Navidad, northwest of Manzanillo, Agapito Garcia Martinez, security manager at the Grand Bay Hotel-Isla Navidad Resort, said Monday that hotel staff were preparing, like taking in beach furniture and protecting hotel windows, but had not yet been advised by authorities to so.

Weather was still sunny despite stronger-than-usual winds and guests were still checking in normally to the hotel, he said. But that could change by today, when Andres drew closer, he noted.