Tropical Storm Alex is expected to reach hurricane strength sometime Tuesday as officials in northern Mexico and Texas prepared for the worst by distributing sandbags and readying emergency shelters.
The eye of the storm has moved away from the Louisiana coast and was headed toward south Texas.
Forecasters with the U.S. National Hurricane Center in Miami said the storm's likely path would take it away from the site of the huge Gulf of Mexico oil spill off Louisiana's coast, but added that it might push oil farther inland and disrupt cleanup efforts.
Forecaster Todd Kimberlain said conditions Monday led the center to conclude the storm would be a less powerful hurricane than initially thought.
However, high winds could still be a problem if they are strong enough to churn the oily waters.
Stacy Stewart, senior hurricane specialist at the U.S. hurricane center, said early Monday that Alex's center wasn't expected to approach the oil spill site, but the storm's outer wind field could push more oil onto land and hinder operations in the area.
The storm could shut down the cleanup effort for roughly two weeks and possibly force crews to pull the cap off the well -- doubling the amount of oil gushing into the Gulf.
"We know that the weather over the next few days - with the wind currents, with the waves - we know this oil will continue to be pushed into our coast, into our wetland," said Louisiana Gov. Bobby Jindal,.
Gobs of oil have washed up on beaches near Biloxi, Miss., making it the fourth state to be directly affected by the spill.
Vice President Joe Biden is scheduled to visit New Orleans and Pensacola, Fla, Tuesday for a firsthand look at the spill's damage.