Tropical Storm Humberto strengthened into a hurricane on Thursday as it approached the Texas coast, packing 80 mph (129 kph) winds and promising more rain and possible flooding.
At 1:15 a.m. EDT (0515 GMT), the center of the hurricane was about 20 miles (30 kilometers) east of Galveston and about 15 miles (24 kilometers) south of High Island. It was moving toward the north-northeast near 8 mph (13 kph).
Forecasters warned residents along a 220-mile (355-kilometer) stretch of coastline extending into southwestern Louisiana to brace for the storm, which was expected to slosh ashore south of Houston overnight.
The storm's center was expected to come ashore between High Island and Sabine Pass early Thursday, the National Weather Service said. A hurricane warning was issued from east of High Island, Texas, to Cameron, Louisiana.
The storm's rain bands were spreading over the coast and between 5 and 10 inches (12 to 25 centimeters) of rain was expected, with some spots possibly getting as much as 15 inches (38 centimeters). But authorities said evacuations were not necessary.
The area expected to be hit the hardest is in the far southeast corner of Texas from Galveston Island eastward. It includes the Beaumont and Port Arthur areas.
Texas has had one of the wettest summers on record, with Houston soaked under the most rain it's had in a summer since 1942. With the ground already saturated, flooding was likely.
In Austin, Gov. Rick Perry activated 50 military vehicles with 200 soldiers, plus a half-dozen helicopters and two swift-water rescue teams. Other crews from the U.S. Coast Guard were on standby.
"Some areas of our state remain saturated by summer floods, and many communities in this storm's projected path are at high risk of dangerous flash flooding," Perry said.
The warning area included Louisiana's Cameron Parish, which was devastated by Hurricane Rita in September 2005. More than 500 federally issued travel trailers and mobile homes remain there.
Louisiana Gov. Kathleen Blanco declared a state of emergency. Shelters were on standby in some areas, and sandbags and sand were being made available, officials said.
Last month, at least six deaths were blamed on Tropical Storm Erin, which dropped nearly a foot of rain in parts of San Antonio, Houston and the Texas Hill Country.