Texas Gov. Greg Abbott has activated about 700 members of the state National Guard ahead of Hurricane Harvey making landfall.
His office said Thursday that Abbott has also spoken with Louisiana Gov. John Bel Edwards and U.S. Department of Homeland Security officials as Harvey strengthens into a major hurricane heading toward Texas.
Military helicopters were on standby in Austin and San Antonio in preparation for search and rescues and emergency evacuations. Harvey is set to become the first hurricane to make landfall on the Texas coast since Hurricane Ike in 2008.
Republican Lt. Gov. Dan Patrick is urging Texans to keep close watch on Harvey. He says "no one should go to bed thinking the track of the storm is set."
The head of the National Weather Service says Hurricane Harvey is "a grave risk to the folks in Texas."
National Weather Service director Louis Uccellini told The Associated Press on Thursday that meteorologists expect "at least a category 3" storm with winds of 111 mph or higher.
Uccellini says "it's a very dangerous storm." He says it's a "potentially impactful storm" that will last over several days and produce large rains from Texas into Louisiana.
Uccellini says Harvey is a risk to people with extremely heavy rainfall that causes inland flooding lasting through the middle of next week, a large storm surge and high winds. A storm surge is an abnormal rise of water above the normal tide, generated by a storm.
Uccellini also notes that the storm is intensifying as it approaches land.
The National Hurricane Center is calling Hurricane Harvey life-threatening and said its track may keep it strong and kicking longer than they previously thought, into early next week.
The National Hurricane Center says Hurricane Harvey is expected to bring life-threatening and devastating flooding from heavy rainfall and storm surge, which is an abnormal rise of water above the normal tide.
The center says Harvey is expected to approach the middle Texas coast Friday and make landfall by that night or early Saturday. It then will likely stall near the coast or just inland through the weekend.
The updated forecast keeps Harvey as a tropical storm through midweek. The storm is expected to produce up to almost 3 feet (0.91 meter) of rain in some areas of the middle and upper Texas coast through next Wednesday. During the same period it's expected to produce more than 1 foot (0.3 meter) of rain in far South Texas and the central parts of Texas and Louisiana.
Two counties have ordered mandatory evacuations as Hurricane Harvey gathers strength as it drifts toward the Texas Gulf Coast.
A predicted storm surge of 6 feet (1.83 meters) to 10 feet (3.05 meters) has prompted Calhoun County officials to order the 22,000 residents of the low-lying coastal county to move inland, as have San Patricio County officials with its 68,000 residents. A storm surge is an abnormal rise of water above the normal tide, generated by a storm.
Brazoria County officials have ordered the evacuation of the Gulf side of the Intracoastal Waterway, including the coastal communities of Treasure Island, Surfside Beach and Quintana. Matagorda County officials have ordered the Gulf side of Farm Roads 521 and 2611 and Texas 35 Business evacuated, including Palacios, Matagorda, Collegeport, Chinquapin and Sargent. The coastal towns of Aransas Pass and Port Aransas also have been ordered evacuated, and voluntary evacuations have been advised for Corpus Christi
Houston airports still expect to stay open after Hurricane Harvey hits South Texas, but airlines are encouraging customers to change travel plans.
United, Southwest and American offered waivers for customers scheduled to fly to, from or through Houston and several other Texas cities from Friday through Sunday. Delta's waiver of additional charges for changing plans runs through Saturday.
Airlines routinely cancel flights when bad weather is expected, although only a few have been scrapped so far, according to tracking service FlightAware.com.
Bill Begley, a spokesman for Bush Intercontinental and Hobby airports, says crews are clearing debris from drains and checking pump stations to prevent flooding.
Begley says the airports plan to stay open, but that could change based on what they hear from the airlines and federal aviation officials.
President Donald Trump is asking people to get ready for Hurricane Harvey.
On Twitter Thursday, Trump said: "As (hash)HurricaneHarvey intensifies - remember to (hash)PlanAhead." He then posted links to websites for the Federal Emergency Management Agency, the National Hurricane Center and a Homeland Security site with tips for emergency preparedness.
A White House spokeswoman says Trump is getting updates on the storm as it approaches the Texas coast. Sarah Huckabee Sanders said Thursday at a news briefing that Trump has "been briefed and will continue to be updated as the storm progresses."
Trump's recently appointed Chief of Staff John Kelly previously served as Homeland Security Secretary. Sanders said there was "no better chief of staff" for Trump "during the hurricane season."
The National Hurricane Center says winds of 125 mph (201 kph) are expected as Hurricane Harvey approaches the Texas coast.
The center said Thursday afternoon that Harvey is expected to become a major hurricane by Friday before it reaches the middle Texas coast. As the hurricane approaches Texas, the hurricane's winds have increased to 85 mph (138 kph).
Center spokesman Dennis Feltgen says, "We're forecasting continuing intensification right up until landfall."
The hurricane is expected to make landfall in Texas on Friday night or early Saturday, then stall near the middle Texas coast through the weekend.
The hurricane is expected to produce up to 20 inches (51 centimeters) of rain and up to 30 inches (76 centimeters) of rain in isolated areas over the middle and upper Texas coast through early next week.
At least two cities along the Texas Gulf Coast are ordering mandatory evacuations as Hurricane Harvey approaches the coastline.
The cities of Port Aransas and Aransas Pass issued evacuation orders Thursday, hours before forecasters expect heavy winds and rain from the storm to begin. Together, the towns are home to around 12,000 people, located next to the Gulf of Mexico.
Aransas Pass police have warned residents that rescuers may not be able to reach them during the storm.
Authorities have placed nearly the entire Texas Gulf Coast under a hurricane or tropical storm watch. Other cities and towns along the 367-mile (591-kilometer) coastline have urged residents to prepare their homes for a storm that could stall inland for as many as three days.
The National Hurricane Center says Tropical Storm Harvey is now Hurricane Harvey and is forecasting it will become a major hurricane to hit the middle Texas coastline.
Sustained winds have reached 80 mph (129 kph). A major hurricane means winds greater than 110 mph (177 kph).
Forecasters said a "life-threatening" storm surge along with rains and wind were likely as Harvey was intensifying faster than previously forecast.
Landfall was expected late Friday between Port O'Connor and Matagorda Bay, a 30-mile (48-kilometer) stretch of coastline about 70 miles (110 kilometers) northeast of Corpus Christi.
The hurricane center says it's possible the storm then could just stall inland for as many as three days, exasperating the threat of severe flooding.
The last major hurricane to hit Texas was Ike, in September 2008. It brought winds of 110 mph (177 kph) in the Galveston and Houston areas and left damages of $22 billion.
A hurricane warning issued along Texas' coast spans a region home to roughly 1.4 million people.
The warning was issued Thursday after Tropical Storm Harvey regained strength while drifting into the Gulf of Mexico. The storm is expected to make landfall late Friday or early Saturday.
The storm has placed nearly the entire 367-mile (591-kilometer) Texas Gulf Coast under a hurricane or tropical storm warning or watch.
Of the people in 16 counties under a hurricane warning, about 325,000 of them are in Corpus Christi. Another 12 million people are under a tropical storm warning, including San Antonio and Houston.
Numerous cities have been bringing in sandbags, extra water and other items ahead of the storm.
Long lines are forming at grocery stores as Texas Gulf Coast residents prepare for a slow-moving tropical storm expected to drop as many as 20 inches of rain.
A hurricane warning was issued Thursday morning for most of the central and southern Texas coast, after Tropical Storm Harvey regained strength while drifting into the Gulf of Mexico.
The storm is expected to make landfall late Friday or early Saturday.
The National Weather Service says it's been 14 years since a hurricane made landfall along the southern portion of the Texas coast.
Forecasters say 10 to 15 inches of rain could fall between Friday and Tuesday in most area, with higher amounts in some places.
The warning, issued Thursday morning, covers an area from Port Mansfield to Matagorda.
The storm's maximum sustained winds are near 45 mph (75 kph) but the U.S. National Hurricane Center says Harvey is expected to strengthen to 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).
Harvey has regained tropical storm strength as it drifts in the Gulf of Mexico toward Texas, and forecasters say it could become a hurricane.
By early Thursday, the storm's maximum sustained winds had increased to near 45 mph (70 kph). The U.S. National Hurricane Center says additional strengthening is expected and Harvey could become a hurricane on Friday.
The tropical storm is centered about 410 miles (660 kilometers) southeast of Port Mansfield, Texas, and is moving northwest near 7 mph (11 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.
Watch News 6 for more updates.
Copyright 2017 by WKMG ClickOrlando. The Associated Press contributed to this report. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.