Millions of Texas residents on Friday were bracing for a potentially "life-threatening" storm as Hurricane Harvey was "dangerously approaching" the US state as a Category 2 storm with the potential to wreck havoc and dump up to three feet of rain.
Fuelled by warm Gulf of Mexico waters, Harvey would be the first major hurricane to hit Texas city in nine years, according to the forecasters.
The "life-threatening storm", could bring up to three feet of rain, 125 mph winds and 12-foot storm surges.
"Recent data from a NOAA Hurricane Hunter aircraft indicated #Harvey has strengthened with estimated 100 mph and is now a Category 2 storm", National Weather Service (NWS) Houston tweeted.
It said the hurricane was approaching with and less than 36 hour out from landfall along the middle Texas coast.
Harvey is forecast to hit the Texas Gulf Coast as a Category 3 hurricane with winds of 115 mph, bringing a storm surge and flash flooding, the NWS said.
The weather agency was blunt in its warning, saying the storm was "dangerously approaching the Texas Coast" where it could linger for days and could spin back ashore to regenerate as it heads toward Louisiana.
"Texas is about to have a very significant disaster", Brook Long, director of the Federal Emergency Management Agency, was quoted as saying by the CNN.
He warned that a "significant inland flood event over many counties" was expected.
Texas Governor Greg Abbott has declared a State of Disaster for 30 counties and requested 700 National Guard members to be activated.
"A lot of people are taking this storm for granted thinking it may not pose much of a danger to them. Please heed warnings and evacuate as soon as possible", Abbott told a local television station.
Schools and universities in Houston and nearby areas have cancelled classes as Harvey continues to gain strength.
School districts across Houston have also cancelled extra-curricular activities scheduled for today and this weekend.
While it has been nine years since Texas last saw a hurricane, the state is no stranger to devastating flooding from tropical systems.
In 2001, Tropical Storm Allison was a multi billion-dollar disaster for the state, specifically Houston.
In Corpus Christi, where Harvey will likely make landfall, a voluntary evacuation has been ordered. Long lines for grocery and essentials were seen at stores as the city cancelled Friday's dockets in city court and provided self-serve sandbags to residents.
Port Aransas on Mustang Island and nearby Portland issued mandatory evacuation orders.
"The system is likely to slow down once it reaches the coast, increasing the threat of a prolonged period of heavy rain and flooding across portions of Texas, southwest Louisiana, and northeastern Mexico into early next week", the National Hurricane Center warned this week.
Meanwhile, residents along the Texas coast aren't taking any chances. They're filling sandbags, stocking up on water and boarding up windows.