MIAMI (AP) — Harvey regained tropical storm strength as it drifted in the Gulf of Mexico toward Texas early Thursday and forecasters said it could become a hurricane.

A hurricane warning was issued for the Texas coast Thursday morning, covering an area from Port Mansfield to Matagorda.

The storm's maximum sustained winds had increased to near 45 mph (70 kph). The U.S. National Hurricane Center said additional strengthening was expected and Harvey could become a hurricane by Friday, when it's expected to approach the southern Texas coast.

As of 5 a.m. EDT, the storm was centered about 370 miles (595 kilometers) southeast of Port Mansfield and was moving north near 10 mph (17 kph).

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.

A hurricane watch was in effect for Texas from Port Mansfield to San Luis Pass. A storm surge watch was in effect from Port Mansfield to High Island.

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.