Update 12.45pm
Tropical Storm Harvey has made landfall for a second time, bringing heavy rain to Louisiana after causing catastrophic flooding in Texas.
The storm has killed at least 18 people and forced tens of thousands to leave their deluged homes in Houston and other parts of Texas.
Although the weather system has weakened considerably, the National Hurricane Centre has warned "flooding rains" will drench southwestern parts of Louisiana.
It is bringing maximum sustained winds of 70km/h to the state.
A volunteer loads sand bags on a pallet as others fill them for resident distribution, Tuesday, Aug. 29, 2017, at the Burton Coliseum in Lake Charles, Louisiana. Picture by: Rogelio V. Solis/AP/Press Association Images
The latest forecast brings much-needed respite for the city of Houston, with less than 2.5cm of rain and potentially some sunshine expected on Wednesday.
But the danger in Texas is far from over, with people in the city of Port Arthur struggling to evacuate their homes as floodwaters rise.
Local officials are struggling to get to the scene to offer assistance, and residents have been urged to get to higher ground in the meantime.
Port Arthur mayor Derrick Freeman said: "The city is underwater right now but we are coming!"
After making its way through Louisiana, Harvey is expected to take its downpours northwards - with Arkansas, Tennessee and parts of Missouri on alert for floods in the coming days.
Donald Jones, a forecaster with the National Weather Service, said: "We aren't going to be dealing with it for too much longer. It's going to pick up the pace and get out of here."
Nearly a third of Harris County, home to Houston, is currently underwater - an area 15 times the size of Manhattan.
US President Donald Trump and First Lady Melania Trump walk to board Marine One before departing the White House for Joint Base Andrews, en route to Corpus Christi, Texas | Image: Yin Bogu/Xinhua News Agency/PA Images
Storm of 'epic proportion'
President Donald Trump visited the affected area on Tuesday, telling rescue organisers: "This was of epic proportion, nobody has ever seen anything like this."
Local officials say it may take days for all of the floodwaters to recede, amid concerns that the number of known fatalities could begin to soar.
The 18 confirmed dead so far include a former football coach who was helping to rescue people trapped in high water.
Meanwhile, tributes have been paid to a Houston police sergeant who drowned as he attempted to drive to work on Sunday.
In Beaumont, a city northeast of Houston, a woman clutching her baby daughter was swept into a rain-swollen drainage canal. Police say the baby was saved but the mother died.
According to local media reports, four volunteer rescuers are also missing after their boat was swept away by a fast-moving current.
Houston is America's fourth-largest city, and officials are now preparing to temporarily house an estimated 19,000 people. Thousands more are expected to flee.
At least 50,000 homes are known to have suffered flood damage, and this number is certain to rise.
Analysts are predicting the economic cost of Harvey could reach $75bn (€63bn) in southeast Texas alone.
