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BROWNSVILLE, Texas -- Hurricane Alex churned westward through the Gulf of Mexico early Wednesday, far from oil spill cleanup efforts but on a collision course with Mexico and the southern Texas coastline.

The National Hurricane Center in Miami upgraded the storm to a Category 1 hurricane -- the least powerful type -- shortly before 10 p.m. CDT Tuesday after measuring sustained winds of 75 mph. Alex became the first June hurricane in the Atlantic since 1995, the center said.

Texas residents had been preparing for the storm for days, readying their homes and businesses and stocking up on household essentials. But the storm was expected to deal only a glancing blow to the state and to make landfall Wednesday evening south of Matamoros, Mexico, and some 100 miles south of Brownsville.

The storm was expected to pack winds of at least 90 mph when it comes ashore, but wasn't expected to become one of the more powerful categories of hurricane.

As of 2 a.m. Wednesday, Alex was 255 miles southeast of Brownsville moving west at about 5 mph, with sustained winds of 80 mph.

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Coastal residents and vacationers looking forward to the Fourth of July weekend began preparing in earnest Tuesday for the storm.

Oil rigs and platforms in the path of the storm's outer bands were evacuated, and President Barack Obama issued a pre-emptive federal disaster declaration for southern Texas counties late Tuesday.

The three oil rigs and 28 platforms evacuated are not part of the Gulf oil spill response. Alex is projected to stay far away from the spill zone and not effect recovery efforts, but tall waves kicked up by the farthest reaches of Alex did toss oil-soaking boom around the water.

Texas also watched Alex's outer bands warily. Alex was expected to bring torrential rains to a Rio Grande delta region that is ill suited -- both economically and geographically -- to handle it.

Passing showers Tuesday quickly pooled along parts of downtown streets in Brownsville and Matamoros, a worrisome sign with Alex expected to dump eight to 12 inches of rain in the region and as much as 20 inches in isolated areas.

In Matamoros, cab driver Alfonso Lopez said he worried that that people would wait until the last minute to take the storm seriously.

"A lot of people trust too much that it won't be very bad or it will change course," he said.

In Cameron County, one of the poorest areas of the U.S. and Texas' southernmost point, Brownsville Mayor Pat Ahumada said he would wait to make his city's emergency declaration in part because the city is cash strapped and he did not want to start paying city workers extra before absolutely necessary.

On nearby South Padre Island, the mood was less anxious. Although hotels and restaurants looked deserted compared to the crush of vacationers who normally pack the popular vacation spot in the summer, those who stuck around didn't size up Alex as much of a threat.

One couple renewed their wedding vows on the beach as a few campers rumbled their trailers -- reluctantly -- out of the park hours before a mandatory evacuation deadline.

"It's June. It's too soon for hurricanes," said Gloria Santos, of Edinburgh, after hitching her trailer back to her truck.

Jerry Wilson, 50, also didn't think much of Alex while struggling to hoist a painter's pole in fierce gusts. With a cloth rigged to the top of the pole, Wilson was cleaning his 10 cameras across the island that will let Internet viewers watch Alex's arrival live online.

"We got two generators and lots of guns and ammo, so we're not worried about it," Wilson said.

The National Weather Service said a hurricane warning was in effect Tuesday for Cameron, Willacy and Kenedy counties. The coastal warning covered Baffin Bay and 100 miles south to the mouth of the Rio Grande.

In Matamoros, government workers stuck duct-tape in X's across the windows Tuesday of the immigration office at the main downtown bridge. Trucks cruised slowly down residential streets, replacing people's large drinking water jugs and cars packed supermarket parking lots.

Matamoros Civil Protection Director Saul Hernandez said they would begin evacuating about 2,500 people from coastal areas east of the city Wednesday morning. But Hernandez said his real concern was the 13,000 families in 95 of the city's low-lying colonias, unincorporated areas where residents frequently have no public utilities or city services.

He urged residents to make their own preparations to ride out the storm.

"This is where we live," he said. "We have to confront it."