Tropical Storm Isaac swirled into the Gulf of Mexico on Monday, disrupting U.S. offshore energy production and threatening to hit Louisiana as a hurricane seven years to the day after devastating Hurricane Katrina.
The storm swiped south Florida on Sunday 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 U.S. National Hurricane Center 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 Aug. 29, 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 Monday morning, Isaac was about 405 miles southeast of the mouth of the Mississippi River with top sustained winds of 65 mph and moving west-northwest at 14 mph.
Its was expected to be centered over the Gulf Coast late Tuesday night or early on Wednesday. Evacuation orders for some low-lying parts of the Gulf Coast already were in effect Monday morning.
Energy producers in the Gulf worked to shut down some of their operations ahead of what could be the biggest test for U.S. 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, Miss., 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 on Tuesday. In its latest advisory, the National Hurricane Center (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 of storm surge if it occurs at the time of high tide in the southeast Louisiana, Mississippi and Alabama coast," she said.
Schauer said the NHC's hurricane warning area included "quite a few oil rigs" but not perhaps the heart of the U.S. offshore oil patch, which produces about 23 percent of U.S. oil output and 7 percent of its natural gas.
With the threat to offshore oil infrastructure and Louisiana refineries, U.S. crude oil prices were up 75 cents to $96.90 a barrel in early trading Monday.
Meteorologists at Weather Insight, an arm of Thomson Reuters, predict the storm will spur short-term shutdowns of 85 percent of the U.S. offshore oil production capacity and 68 percent 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 percent of U.S. refining capacity.
That could send gasoline prices spiking just ahead of the 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 on Sunday.
London-based BP, the biggest U.S. Gulf producer, said it was shutting production at all of its Gulf of Mexico oil and gas platforms and evacuating all workers on Sunday.
Isaac'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 on Monday but official events were delayed until Tuesday because of the storm.
Tampa still faces total rain accumulations of about 15 inches between Sunday and Monday evening, 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 on Sunday. 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 on Sunday.
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