By Gerardo Garcia
CHETUMAL, Mexico (Reuters) - Tropical Storm Alex was becoming more organized as it moved over the Yucatan Peninsula and has at least a moderate chance of becoming a major hurricane as it crosses the Gulf of Mexico, the U.S. National Hurricane Centre said on Sunday.
The storm was not an imminent threat to oil-siphoning efforts at BP Plc's blown-out Macondo well in the Gulf, the U.S. Coast Guard said on Saturday.
Alex was expected to emerge in the southern Gulf of Mexico on Sunday and make landfall again as a hurricane later in the week between Brownsville, Texas, and Tuxpan de Rodriguez Cano, Mexico, sparing BP spill collection efforts. But the Hurricane Centre said models varied widely on its possible track.
In its 7 a.m. EDT (Noon British time) forecast, the hurricane centre said Alex has become a more organized storm as it crossed over Belize and the Yucatan Peninsula, and there was at least a moderate chance it could become a major hurricane. That is a category 3 or higher, with winds of at least 111-130 miles per hour (178-209 km/hr).
Alex, the first named storm of the 2010 Atlantic hurricane season, had sustained winds of near 40 miles per hour (65 km per hour) and was located about 55 miles (90 km) southwest of Chetumal, Mexico.
On Saturday, Quintana Roo state authorities evacuated 200 people from fishing villages across the Chinchorro reef, near Belize, and Xcalak, famous for its diving spots.
Some rain fell over Cancun, a major seaside resort that draws U.S. and European visitors, but there was no threat to some 35,000 tourists in the area, civil protection said.
Alex was moving west-northwest at 12 mph (19 kph) but its speed should decrease as it moves over land.
"Strengthening is forecast on Sunday night and Monday after Alex moves over the southern Gulf of Mexico," the centre said.
A tropical storm warning was in effect for the coast of Belize and the east coast of Mexico's Yucatan Peninsula from Chetumal to Cancun. The hurricane centre said the warning would likely be lifted later on Sunday.
Alex was expected to bring 4 to 8 inches (10 to 20 cm) of rain to the Yucatan Peninsula, southern Mexico, northern Guatemala, Honduras and Belize through Monday morning. Isolated amounts of up to 15 inches (38 cm) were possible over mountainous areas.
"These rains could cause life-threatening flash floods and mudslides," according to the centre.
The Atlantic hurricane season runs from June 1 to November 30 and meteorologists predict this year will be a very active one. Hurricanes feed on warm water and the sea surface temperatures in the tropical Atlantic are higher than usual this year.
In the Pacific, hurricanes Darby and Celia weakened to tropical storms as they continued to dissipate.
(Additional reporting by Jose Cortazar in Cancun and Cyntia Barrera Diaz in Mexico City, editing by Vicki Allen)