‘Wake-up call.’ Early storms redefine hurricane season

By Thomas Frank | 05/22/2020 06:41 AM EDT

Tropical storms arrived at the United States’ doorstep before hurricane season started in each of the last six years. Scientists are now thinking about extending the season.

Tropical Storm Arthur passes by the East Coast on Monday. Atlantic storms seem to be forming earlier in the year.

Tropical Storm Arthur passes by the East Coast on Monday. Atlantic storms seem to be forming earlier in the year. NOAA

NOAA released its annual hurricane outlook yesterday, warning the nation to prepare for an unusually large number of Atlantic storms.

But the forecast had one problem.

Hurricane season had already begun.


Tropical Storm Arthur skirted along the North Carolina coast early this week, bringing heavy rain, 50-mph winds and dangerous surf conditions two weeks before the official start of the Atlantic hurricane season on June 1.

It was the sixth year in a row that a named storm formed in the Atlantic before June, prompting NOAA to consider changing the season’s start date as some scientists called it archaic in an era of climate change.

"June 1 is not a magic date. If they are starting earlier, we should have people being prepared earlier," said Jennifer Francis, a climate scientist at Woods Hole Research Center.

Moving hurricane season into mid-May or earlier would be a "wake-up call" about climate change, which is intensifying storms, Francis said.

Acting NOAA Administrator Neil Jacobs said yesterday that changing the start date "is something we’ve been looking at."

But agency forecasters say the trend of earlier-forming storms might be a function of better monitoring and a policy of giving names to weaker storms that would not have been designated previously.

"It’s not necessarily a climate signal that we’re seeing with these May storms. It may just be that they weren’t recorded before for various reasons," Gerry Bell, lead hurricane season forecaster for NOAA’s Climate Prediction Center, said yesterday in a conference call with journalists.

NOAA began naming subtropical storms in 2002; they have maximum sustained winds below 39 mph. Before then, names were only given to tropical storms, which have sustained winds between 39 and 73 mph, and to hurricanes, which have sustained winds of 74 mph or higher.

NOAA records show that there have been 10 named storms before June 1 in the 19 years since 2002.

Three of them were subtropical storms, including Andrea, which formed near Bermuda on May 20, 2019, and Alberto, which formed between Cuba and Mexico on May 25, 2018.

"We’re naming about two more a year of these weak, short-lived storms that were just not [previously] observed in the record," Bell said. "By far the bulk of the season is August, September and October. That’s when by far you have the most hurricanes and major hurricanes."

The start date of the Atlantic hurricane season is largely a public relations effort to get people along the East Coast and Gulf Coast to prepare for deadly storms. It is preceded in early May by National Hurricane Preparedness Week, which features reminders from agencies such as the National Weather Service and the Federal Emergency Management Agency.

Hurricane preparation has been unprecedented this year as officials scrambled to find alternatives to community shelters that handle hundreds or thousands of hurricane evacuees. Those will be scaled down because of the need for social distancing during the COVID-19 pandemic.

NOAA said yesterday that there are likely to be three to six major Atlantic hurricanes this year, though it is unclear how many will make landfall in the United States or the Caribbean.

In typical years, many communities do little to prepare for hurricanes, prompting some officials to question the value of an earlier start date to the season.

"They don’t get ready for June 1; why would they get ready for May 15?" said Craig Fugate, who was FEMA administrator from 2009 to 2017. "We use these dates to rally around. But how many times have you seen a hurricane response where people weren’t lining up at the last minute getting supplies? Moving that date won’t change that."

Since 1954, only two hurricanes that made landfall in the United States before June 1 have caused enough damage to be declared a major disaster, FEMA records show. Both of those hurricanes occurred in 1957, hitting Texas in late April and Louisiana in mid-May.

Texas State Climatologist John Nielsen-Gammon called the start date of hurricane season "not so much a scientific question as a sociological question." He said early storms can be damaging despite their lower wind speeds because they form close to the U.S. mainland.

"They’re dangerous because you typically don’t have much warning between when the storm forms and when it can be affecting the United States," said Nielsen-Gammon, a professor at Texas A&M University. "In the peak of hurricane season, they form over the Atlantic, and you can see them coming for several days. But storms forming over the Gulf of Mexico or the Bahamas are only a few hundred miles from land when they form.

"We certainly know that storms can happen earlier than June 1," Nielsen-Gammon added. "So given that track record, it makes sense to be talking about the start of hurricane season as something that begins before we actually start getting hurricanes."

Bell, the NOAA forecaster, agreed that early-season storms can cause extensive damage and that an earlier starting date to the hurricane season could help preparations.

"Some of these short-lived storms, you need to be ready, because a slow-moving tropical storm can provide 10 or 15 inches of rain over a big area and can produce a lot of inland flooding," Bell told reporters. "Those are the type of preparations that can be accelerated once you have a fixed start date to the season."

The role of climate change in Atlantic hurricanes is unclear.

A study published Monday in the Proceedings of the National Academy of Sciences found that human-induced climate change has increased the likelihood of major hurricanes — those with maximum sustained winds of at least 111 mph — around the world. The study was written by researchers at NOAA and the University of Wisconsin.

But yesterday, NOAA officials said it’s not clear that climate change is currently affecting hurricanes in the Atlantic. Hurricane patterns are influenced primarily by a natural environmental phenomenon called the Atlantic Multidecadal Oscillation, which results in sea-surface temperatures fluctuating every few decades.

"There may not be any global warming signal to be seen in the Atlantic yet, because these other signals are so huge," Bell said.

But Pennsylvania State University climate researcher Daniel Brouillette said climate change is causing sea-surface temperatures to increase earlier each year.

"That probably has something to do with storms forming earlier," Brouillette said. "With storms routinely occurring in May, it’s important for emergency managers, policymakers and the general public to make preparations earlier."