Tropical Storm Isaac swirled into the Gulf of Mexico today, disrupting US offshore energy production and threatening to hit Louisiana as a hurricane seven years to the day after devastating Hurricane Katrina.
The storm poses risks to life and could cause extensive damage to states along the US Gulf Coast with a storm surge of up to six to 12 feet, US federal emergency officials said today.
"There are some aspects of this storm that are very concerning, particularly storm surge as well as now potentially heavy rainfall across the area of impact," Federal Emergency Management Agency Administrator Craig Fugate said in a conference call with reporters.
The storm swiped south Florida yesterday before moving into warm Gulf waters, where it is expected to strengthen into at least a Category 1 hurricane.
On its current track, Isaac was due to slam into the Gulf Coast anywhere between Florida and Louisiana by midweek, the US National Hurricane Centre said.
The governors of Alabama, Louisiana and Mississippi declared states of emergency as a hurricane warning went into effect for the northern Gulf Coast from Louisiana to the Florida Panhandle.
It included New Orleans, devastated when Hurricane Katrina swept over the city on August 29th, 2005, killing more than 1,800 people and causing billions of dollars of damage along the coast.
"It is difficult to realize that to the day - seven years after Katrina - another hurricane is headed our way," Mississippi Governor Phil Bryant said.
Early this morning, Isaac was about 650km (405 miles) southeast of the mouth of the Mississippi River with top sustained winds of 100 km/h (65mph) and moving west-northwest at 24 km/h (14 mph).
Its was expected to be centered over the Gulf Coast late tomorrow night or early on Wednesday.
Evacuation orders for some low-lying parts of the Gulf Coast already were in effect this morning.
Energy producers in the Gulf worked to shut down some of their operations ahead of what could be the biggest test for US energy installations since 2008, when Hurricanes Gustav and Ike disrupted offshore oil output for months and damaged onshore natural gas processing plants, pipelines and some refineries.
Gulf residents started stocking up on supplies and securing their homes. In New Orleans, long lines formed at some gas stations and in Gulfport, Mississippi, people crowded supermarkets to buy bottled water and canned food.
"I sense a high level of anxiety," said New Orleans Mayor Mitch Landrieu.
"The timing, as fate would have it, on the anniversary of Katrina has everybody in a state of alertness, but that is a good thing."
Isaac is forecast to become a hurricane tomorrow.
In its latest advisory, the National Hurricane Centre (NHC) said the storm was not expected to strengthen beyond Category 1, the weakest type on the five-step Saffir-Simpson scale of hurricane intensity.
NHC meteorologist Jessica Schauer said Isaac could trigger widespread coastal flooding, however.
"Right now we're forecasting 6 to 12 feet (1.8-3.6m) of storm surge if it occurs at the time of high tide in the southeast Louisiana, Mississippi and Alabama coast," she said.
Ms Schauer said the NHC's hurricane warning area included "quite a few oil rigs" but not perhaps the heart of the US offshore oil patch, which produces about 23 per cent of US oil output and 7 per cent of its natural gas.
With the threat to offshore oil infrastructure and Louisiana refineries, US crude oil prices were up 75 cents to $96.90 a barrel in early trading today.
Meteorologists at Weather Insight predict the storm will spur short-term shutdowns of 85 per cent of the US offshore oil production capacity and 68 per cent of the natural gas output.
Once ashore, the storm could wreak havoc on low-lying fuel refineries along the Gulf Coast that account for about 40 per cent of US refining capacity.
That could send gasoline prices spiking just ahead of the US Labor Day holiday, analysts said.
"It's going right in the heart of refinery row," Phil Flynn, an analyst with Price Futures Group in Chicago, said yesterday.
London-based BP Plc, the biggest US Gulf producer, said it was shutting production at all of its Gulf of Mexico oil and gas platforms and evacuating all workers yesterday.
Issac's westward track meant the worst of its weather would miss Tampa, where the Republican National Convention was expected to open its four-day meeting today but official events were delayed until tomorrow because of the storm.
Tampa, located on Florida's west coast, still faces total rain accumulations of about 15 inches (38 cm) between yesterday and tonight, forecasters said.
In south Florida, winds from Isaac forced cancellations of hundreds of flights in and out of Miami, Fort Lauderdale and other south Florida airports yesterday. Miami-Dade Mayor Carlos Gimenez reported more than 500 cancellations affecting Miami International Airport alone.
The storm killed at least nine people and caused significant flooding and damage in Haiti and the Dominican Republic before sweeping across the southern tip of Florida yesterday.
Reuters