Tropical Storm Bud lashed the west coast of Mexico late Friday, but the first serious eastern Pacific storm of the 2012 season was rapidly losing strength, giving Mexican emergency officials some respite.

However, a new storm named Beryl has formed in the Atlantic, threatening to disrupt the plans of thousands of US beachgoers taking advantage of the long Memorial Day weekend.

Mexican authorities breathed a sigh of relief as Bud displayed weaker wind gusts and lower swells than expected.

Overnight, the storm moved about 155 kilometers (100 miles) west-northwest of the port city of Manzanillo, according to the Miami-based National Hurricane Center (NHC).

It was creeping northward at 11 kilometers (seven miles) per hour, packing maximum sustained winds of 95 kilometers (60 miles) per hour.

"Additional rapid weakening is forecast," the NHC said. "And Bud is expected to weaken to a tropical depression on Saturday."

The weakening notwithstanding, emergency officials had alerted residents and prepared shelters as Bud -- which briefly intensified to a category three storm on the five-level Saffir-Simpson scale -- made its approach.

"We are on alert, we are preparing some 120 shelters in the coastal towns," said Colima civil protection chief Melchor Urusua.

The Mexican government discontinued a hurricane warning along the central Pacific coastline from Manzanillo to Cabo Corrientes, downgrading it to a tropical storm warning.

A tropical storm watch was in effect for the coast from north of Cabo Corrientes to San Blas.

The eye of the storm was expected to move near land overnight from Friday to Saturday before taking a gradual turn toward the southwest away from the coast on Sunday, according to the NHC.

Tropical storm conditions were already affecting part of the coastline.

Bud is expected to drop up to 25 centimeters (10 inches) of rain in the Mexican coastal states of Michoacan, Colima, Jalisco and southern Nayarit, with up to 38 centimeters (15 inches) in isolated areas.

This rainfall could produce "life-threatening" flash floods and mudslides, the NHC said.

Mexican authorities have formed a task force in Jalisco, which includes 31 all-terrain vehicles and two helicopters to deal with emergency situations as well as deliver water and emergency food supplies to towns and villages that might be cut off by flooding

"A storm surge is expected to produce coastal flooding," the NHC warned. "The surge will be accompanied by large and damaging waves."

The center also said that swells generated by Bud could also produce dangerous, even "life-threatening" surf and rip current conditions.

But as Mexico appeared to have dodged the bullet, a new subtropical storm named Beryl formed in the Atlantic off the coast of South Carolina.

Beryl, which was currently located 305 miles (490 kilometers) east of Charleston, South Carolina, was moving north at nine miles (15 kilometers) an hour, the Miami-based center said.

On the projected course, it was expected to hit the coast in one of the southeastern states on Sunday, packing winds of about 45 miles (75 kilometers) an hour.

Beryl formed just as Americans began celebrating the Memorial Day weekend, which marks the unofficial start of the beach season.

The Mexican Meteorological Service has forecast 23 tropical storms of various levels of intensity for the 2012 hurricane season. Ten of them are expected in the Atlantic Ocean and 13 in the Pacific.

"The anticipated storms will be less intense than the average," said Jose Luis Luege, director general of the Mexican National Commission of Water.

The US National Oceanic and Atmospheric Administration has predicted a "near-normal" Atlantic hurricane season is likely.

The Atlantic hurricane region includes the northern Atlantic, the Caribbean Sea and the Gulf of Mexico.