Here’s what you need to know:
After some good fortune, the Gulf Coast warily watches an approaching storm.
Tropical Storm Marco significantly weakened before making landfall on Monday night, largely sparing the Gulf Coast the “one-two punch” of back-to-back hurricanes that meteorologists had warned might pummel Louisiana and Texas.
Still, officials in those states implored residents to maintain their vigilance on Tuesday as Tropical Storm Laura continued to gain strength while bounding toward them.
Even before Marco had officially arrived, most eyes were already on Laura, which unleashed heavy rainfall across Cuba and Jamaica. The storm is expected to increase in strength — possibly becoming a major Category 3 hurricane — late Wednesday or early Thursday as it moves through the Gulf of Mexico’s warm waters.
Hurricane conditions are possible from Port Bolivar, Texas, to west of Morgan City, La., according to the National Hurricane Center, which said there was a risk of life-threatening storm surge from San Luis Pass, Texas, to Ocean Springs, Miss.
Gov. John Bel Edwards expressed relief that Louisiana would not be walloped by two hurricanes within 48 hours — a rare occurrence that would have posed formidable challenges for even the most seasoned veterans of Gulf Coast storms.
Marco had been a Category 1 hurricane on Sunday, but it dissipated into a tropical storm on Monday before making landfall near the mouth of the Mississippi River around 6 p.m. local time. It became a tropical depression about three hours later.
“If I’ve got a message, it’s not to assume that Laura is going to do a similar favor” and lose steam the way Marco did, Mr. Edwards said.
Parts of Texas and Louisiana are evacuating before Laura arrives.
Mandatory evacuations have already begun throughout portions of Louisiana and Texas to prepare for Laura’s potential landfall in the United States.
The areas within the storm’s path that have issued mandatory evacuation orders include Port Arthur, Texas, which has the nation’s largest oil refinery, and Cameron Parish, La., just across the state line. Oil and gas companies have also evacuated workers from offshore production platforms in the Gulf of Mexico.
City and county officials in Texas have issued evacuation orders affecting hundreds of thousands of residents, particularly those living in low-lying areas. These orders, some of them voluntary, include parts of Orange, Jefferson and Chambers Counties.
Texas A&M University at Galveston issued a mandatory evacuation order, and Mayor Thurman Bartie of Port Arthur said he planned to issue one for the city effective at 6 a.m. on Tuesday.
Gov. Greg Abbott of Texas also mobilized more than 70 members of the Army and Air National Guards and the Texas State Guard to help local, state and federal officials with the storm response.
“Property and belongings can be restored, but lives cannot,” Mr. Abbott said in a statement on Monday. “I call on all Texans who may be in harm’s way to put their safety and their family’s lives above all else.”
The Texas Department of Criminal Justice said in a statement that staff had begun evacuating several facilities on Monday. Prisoners and employees were transported with N-95 masks and personal protective equipment because of the coronavirus pandemic. The Louisiana Department of Public Safety and Corrections has already moved more than 1,300 inmates.
Cameron Parish, in southwestern Louisiana, issued a mandatory evacuation order effective at 1 p.m. Monday. Portions of Jefferson, Lafourche and Plaquemines Parishes have also ordered residents to evacuate.
“Our sights are on Laura now,” Gov. John Bel Edwards said at a news conference.
Does global warming create more hurricanes in the Atlantic?
Adam Sobel is an atmospheric scientist and the director of the Initiative on Extreme Weather and Climate at Columbia University.
While there is considerable support that warming oceans are making the hurricanes that do occur produce more rain, stronger winds and worse coastal flooding, it has not been clear that it is producing more storms.
Decades ago, we used to think a hotter planet should have more hurricanes because storms like warm ocean water. It turns out it is not that simple. Hurricanes form over the warmest waters on the planet, but as the entire ocean warms, the sea surface temperature threshold needed for storms to form also rises.
That is for the planet as a whole. But the Atlantic Ocean is a special case, both because some of us live near it, and because its climate has some unique features.
The Atlantic has experienced large swings in hurricane activity: The 1950s and 1960s were very active, then the 1970s and 1980s were quiet, and then things picked up again. Those have historically been viewed as natural cycles, implying that we could expect the relatively active period we are in to eventually end.
But there is increasing evidence that the quiet decades were caused by aerosol pollution — tiny particles originating from sulfur out of American and European smokestacks that cooled the ocean by reflecting sunlight. That pollution has been reduced by environmental regulation, and with increased greenhouse gases warming the Atlantic, returning to a low-hurricane period may be less likely.
The Atlantic is also influenced by the Pacific Ocean. Atlantic hurricanes tend to be suppressed in an El Niño and active in a La Niña because of how those Pacific phenomena affect the jet stream.
Climate models have predicted that our warmer future will on average see an El Niño Pacific more often, giving us a reason to predict fewer Atlantic hurricanes. New research by some of my colleagues, though, has made a persuasive case that the models are wrong, despite their consistent predictions for the Pacific.
If so, our expectations for the future of Atlantic hurricanes may have been far too sanguine.
Reporting was contributed by Christina Morales and Rick Rojas.