* Could become hurricane later on Tuesday
* Douses Honduras, Belize with rain
* Expected to make landfall on Yucatan peninsula late Tuesday (Recasts, updates location, adds Cancun details, previous TEGUCIGALPA, changes byline)
By Isela Serrano
CANCUN, Mexico, Aug 7 (Reuters) - Tropical Storm Ernesto doused Honduras and Belize as it churned through the western Caribbean on Tuesday and U.S. forecasters expected it to hit popular Mexican tourist destinations on the southern Yucatan peninsula later in the evening.
Authorities from the Mexican state of Quintana Roo have ordered the evacuation of some 1,500 people in the southern portion of the state, known for its scuba diving and eco-tourism attractions.
While the eye of Ernesto is not expected to hit the region's major resort of Cancun, some rain has started to fall in the area, which is packed with local and international visitors this time of the year.
Cancun, some 230 miles (380 km) to the north of the storm's forecast path, was devastated in 2005 by Hurricane Wilma, the most intense storm ever recorded in the Atlantic.
Ernesto had top sustained winds of 65 miles per hour (105 km per hour) and was located 220 miles (354 km) east of Chetumal, Mexico, the U.S. National Hurricane Center in Miami said on its 11:00 a.m. EDT advisory.
"Ernesto (is) expected to make landfall on the Yucatan peninsula tonight," the NHC said. "Ernesto is expected to become a hurricane before it reaches the Yucatan peninsula."
Hurricane warnings were extended northward to Tulum on the east of the Yucatan peninsula and for the entire coast of low-lying Belize. A tropical storm warning remained in effect for the Atlantic coast of Honduras and Nicaragua.
One cruise ship which was due to dock at the resort island of Cozumel on Wednesday had canceled its visit and another was diverted to Veracruz, in the Gulf of Mexico.
Heavy rain hit northern Honduras early Tuesday but there were no reports of damage, Roger Torres, deputy commissioner of the country's contingency agency told Reuters.
Big ships were conducting business as usual on Honduras' main Atlantic ports although authorities restricted fishing for small boats.
Forecasters expect Ernesto to move into the southern part of the Gulf of Mexico by Wednesday afternoon or evening, but it was too early to know if it could disrupt oil and gas operations in the gulf.
Rainfall of four to eight inches (10 to 20 cm), and possibly 12 inches (30 cm) in some areas, were expected over Belize and the southern portions of the Yucatan peninsula.
"These rains are likely to cause dangerous flash floods and mudslides over higher terrain," the NHC said.
Belize's government said 175 residents of outlying islands had voluntarily moved to safer ground, and five emergency shelters were being set up to house evacuees.
August and September are usually the most active months of the Atlantic-Caribbean hurricane season, which runs from June 1 to Nov. 30. (Additional reporting by Gustavo Palencia on Tegucigalpa, Mike McDonald in Guatemala City and Cyntia Barrera in Mexico City; Editing by Krista Hughes and Eric Walsh)