The National Hurricane Center says Harvey is now a hurricane. The storm gained power Thursday in the Gulf of Mexico and is moving toward the Texas coast.
As of 1 p.m. EDT, the storm's maximum sustained winds had increased to 80 mph.
"Harvey [is] quickly strengthening and forecast to be a major hurricane when it approaches the middle Texas coast," the hurricane center warned.
The latest forecast shows Harvey making landfall late Friday or early Saturday.
CBS affiliate KHOU-TV reports Houston is forecast to receive 5 to 15 inches of rain, and KHOU Meteorologist Chita Craft warns some isolated parts of Houston could receive 20 inches of rain. The National Weather Service said rainfall from Harvey could cause life-threatening flooding.
The storm could be the largest to hit Texas since Hurricane Ike in 2008.
A hurricane warning is in effect for Matagorda and Jackson Counties on the Gulf Coast. A hurricane watch stretches from Port Mansfield to San Luis Pass, and a storm surge watch is in effect from Port Mansfield to High Island.
In Texas, Gov. Greg Abbott has ordered the State Operations Center to elevate its readiness level, making state resources available for possible rescue and recovery actions. Abbott also pre-emptively declared a state of disaster for 30 counties on or near the coast to speed deployment of state resources to any areas affected.
Emergency officials Wednesday asked residents along the upper Texas coastline to move or prepare to move inland. Those in low-lying areas were urged to seek higher ground, and those elsewhere were told to monitor official announcements closely.
On South Padre Island, people filled sandbags and loaded them into cars and vans Wednesday to take to protect exposed homes and businesses. Others in the forecast path of the storm sought out generators, plywood and other goods from hardware stores. Meanwhile, rice farmers in coastal Matagorda County moved quickly to harvest their crops.