AMBERGIS CAYE, Belize—A weak tropical storm formed Saturday off the Yucatan Peninsula and quickly made landfall at the Belize-Mexico border, dumping rain and kicking up surf.

The first named storm of the 2008 Atlantic Hurricane Season, Arthur was moving northwest across the Yucatan with maximum sustained winds near 40 mph (65 kph), according to the National Hurricane Center in Miami.

The storm formed one day before the official start of the season June 1, hitting land near the Mexican port city of Chetumal and Belize’s Corozal city. It dumped rain as far south as Belize City and kicked up strong surf on the popular tourist island of Ambergis Caye.

Tropical storm warnings were issued for Belize and Mexico’s Caribbean coastline.