Hurricane Laura and a taste of the future

Monday, August 31, 2020

EAPS professor Kerry Emanuel on the latest storm to hit the Gulf of Mexico and forecasting catastrophic storms

Hurricane Laura’s rapid intensification is a sign of a warming climate, scientists say (The Washington Post)

“Laura is, unfortunately, an example of the forecaster’s worst nightmare ... rapid intensification of a storm in the day or so leading up to landfall,” said MIT hurricane expert Kerry Emanuel.

Residents flee as Gulf Coast sees possible tandem hurricanes (AP)

The warmer the water, the stronger the fuel for a hurricane.

“It, unfortunately, might peak in intensity about landfall. That’s the one thing I worry about with this one,” MIT meteorology professor Kerry Emanuel said of Laura. His multiple computer simulations show a decent chance of winds of more than 110 mph (177 kph) for Laura at landfall, as do other computer models.

“A forecaster's nightmare": why Laura's rapid intensification worries scientists (Univision)

“It’s the forecaster's nightmare. You go to bed with a tropical storm and wake up with a Cat 4,” said Kerry Emanuel, a hurricane scientist at the Massachusetts Institute of Technology (MIT).

Laura was not quite the worst scenario as it struck a relatively unpopulated region of the coast and there was enough time to evacuate residents by bus before the winds arrived. “We lucked out,” says Emanuel.

To be fair to the forecasters, it’s unfair to expect absolute accuracy, said Emanuel, who is working on a project to incorporate more probability modeling for wind strengths to help homeowners make evacuation decisions.

“No matter how you perfect your models you can’t predict beyond some time horizon. Even if you measure every molecule in the atmosphere you still won’t get there,” he said.

Damage from whopper hurricanes rising for many reasons (AP and NBC News)

But MIT meteorology professor Kerry Emanuel says it’s because another counterintuitive factor is at play: There are more storms because of cleaner air.

European air pollution cooled the area over Africa in the 1960s and 1970s and put more dust into the air — both of which tamped down on any hurricanes, he said. When the pollution eased, Africa got warmer, more storms developed, and that’s why it’s such a busy period, Emanuel said.

While climate change is not the most important factor in warming waters, it contributes to creating more damaging storms in other ways, by causing a rising sea level that worsens storm surges and making storms move more slowly and produce more rain, scientists say.

Recipe for a Busy Hurricane Season: Warmer Water, Cleaner Air (Scientific American)

“From the 1950s to the late 1970s, big time, we were ramping up sulfate emissions, which are a byproduct of fossil fuel combustion,” said Kerry Emanuel, a hurricane expert at the Massachusetts Institute of Technology.

This pollution dampened temperatures in the tropical Atlantic for several decades. And some experts believe that hurricane activity was dampened, as well.

“We think it was mostly a man-made phenomenon, that we caused a kind of hurricane drought in the ‘70s and ’80s,” Emanuel said. ...

There’s still some debate among scientists about whether the pollution was the major factor or whether natural climate cycles played a bigger role, Emanuel noted.

Story Image: Hurricane Laura spins in the Gulf of Mexico on Aug. 26th. (Credit: NOAA)