Tropical Storm Dolly intensified over the warm waters of the western Gulf of Mexico as it bore down on southern Texas on Tuesday, but forecasters don't expect it to reach catastrophic strength before hitting land near the Mexican border on Wednesday.
The storm, with sustained winds of nearly 70 miles per hour (110 km per hour), emerged from the Yucatan Peninsula over the warm waters of the Gulf of Mexico. A hurricane watch was issued for the southern Texas coast, the U.S. National Hurricane Center said.
At 11 a.m. EDT (1500 GMT), Dolly was 230 miles (370 km) southeast of the border town of Brownsville, Texas, where it is due to come ashore on Wednesday as a low-grade hurricane.
The storm's predicted landfall and strength are unlikely to jeopardize sensitive offshore drilling rigs and production platforms in the U.S. and Mexican waters of the Gulf of Mexico. U.S. crude oil prices on Tuesday fell over $4 a barrel.
The United States has largely escaped the past two Atlantic hurricane seasons, with just one hurricane -- Humberto in November 2007 -- making landfall on its coasts.
But it was pummeled in 2004 and 2005, when a series of powerful hurricanes, including the catastrophic Katrina, ravaged Florida and the U.S. Gulf Coast.
The National Hurricane Center said Dolly is unlikely to become a major hurricane prior to landfall, but could dump as much as 15 inches (38 cm) of rain on South Texas and northeastern Mexico in coming days.
The 2008 Atlantic hurricane season is already a month ahead of schedule, but is unlikely to see a repeat of the devastating 2005 season. On average, the fourth tropical storm of the six-month season does not occur until Aug. 29. Dolly, this year's fourth, formed on July 20.
"It absolutely does mean something, and we should be looking at it with trepidation," said Jeff Masters, co-founder of meteorological website The Weatherunderground.
In Texas, Gov. Rick Perry put 1,200 National Guard troops on alert, and told citizens to take precautions, although no mandatory evacuations were ordered.
"We want the citizens to get out their plan, make the decisions on when they're going to go, where they're going to go, but get your batteries and everything stocked up, get your cars full of gasoline," said Henry Garrett, mayor of the coastal city of Corpus Christi.
In Mexico, Dolly had dumped rain in the popular resort of Cancun in the Yucatan Peninsula, but no major damage was reported.
The northeastern state of Tamaulipas on Mexico's Gulf Coast issued a hurricane warning and began preparing dozens of buildings to receive possible evacuees.