UPDATE 3-Tropical storm Arthur churns over Mexico's Yucatan

Sat May 31, 2008 11:13pm BST

(Releads and updates throughout, pvs MEXICO CITY)

MERIDA, Mexico May 31 (Reuters) - Tropical storm Arthur, the first of the year in the Atlantic and the second in the Americas, whipped up strong winds and dumped heavy rains on Saturday as it churned across Mexico's Yucatan peninsula.

Packing sustained winds of near 40 mph (65 kph), Arthur drenched southern parts of Yucatan as well as neighboring Belize and Guatemala, the Miami-based National Hurricane Center said. Up to 10 inches (25 cm) of rain are expected.

"These rains could cause life-threatening flash floods and mud slides, especially in mountainous terrain," the center said.

Arthur, which formed a day before the official June 1 start of the Atlantic hurricane season, was centered 75 miles (125 km) northwest of Belize City.

It was moving westerly at 7 mph (11 kph) and was expected to weaken. It is expected to cross the Yucatan, south of the colonial city of Merida and emerge intact on Sunday in the Bay of Campeche, part of the Gulf of Mexico where there are oil platforms.

"Arthur is expected to weaken to a depression tonight, but it then could regain tropical storm strength if it emerges over the Bay of Campeche," the hurricane center said.

Arthur is seen lingering in the southern part of the Gulf of Mexico until Tuesday, according to a five-day tracking forecast map from the hurricane center.

Small boats were banned from leaving a handful of ports along the Mexican Caribbean coast, according to Nemesio Medina, head of Quintana Roo state government weather center. But conditions were not bad enough to evacuate, he told reporters.

Another tropical storm, Alma, which formed in the Pacific, broke up on Friday over Central America's mountains after slamming into Nicaragua's Pacific coast, killing three people. (Reporting by Jose Cortazar; Writing by Chris Aspin)