Work isn’t finished after hurricane season
If your work involves hurricanes, odds are you’re not planning any family vacations during the months of August, September or October. Forecasters, emergency managers and storm chasers spend months on high alert, carefully monitoring any clump of clouds in the tropical Atlantic for ominous signs of development.
It might surprise you to learn that, after months of being on high alert, meteorologists don’t necessarily get to rest once hurricane season is over. For some, the workload can actually even increase.
At the National Hurricane Center in Miami, for instance, its meteorologists are currently busy, tasked with penning detailed reports on each of the 30 named storms in the Atlantic last year. Hurricane chasers, meanwhile, are already hard at work plotting their moves for the upcoming season.
There are indications that, thanks to a lingering La Niña influence, the 2021 hurricane season may be abnormally active. La Niña, a cooling of the waters in the east tropical Pacific, encourages more rising motion and relaxed upper-level winds over the Atlantic, more conducive to tropical development.
Putting 2020 in the books
Eric Blake, a senior hurricane specialist at the hurricane center, has spent the past few months working on no fewer than seven tropical storm and hurricane reports as his team works to put the historic 2020 season in the books. Each report isn’t just a narrative of what happened and when: It’s a comprehensive synopsis that integrates forecasts from the time with observed data, impacts and scientific analysis.
The reports are instrumental in guiding post-storm public policy and government responses, which in some cases can be linked to the strength and air pressure of a storm at landfall. Sometimes a postseason report will even recategorize a storm based on newly available after-the-fact data.
“This is easily the most reports
I’ve ever had to do,” Blake said. “I finished about half of them, I still have half to go. Some people kind of get the big ones. The longer ones usually require two people. None of the really long ones (from 2020) are out just yet.”
Last year bore witness to a host of destructive storms, including Category 4 Laura, which ravaged southwest Louisiana, as well as Category 4 and 5 Eta and Iota respectively, which lay siege to the same swaths of Honduras and Nicaragua in just two weeks’ time.
“I’m part of the best track change committee,” said Blake, meaning he’s one of several meteorologists who review data to ensure the location and intensity of a storm, which appears on maps in six-hour intervals, is correct. “For climate purposes, it’s important to get the best possible estimate you can.”
Blake has never had to pen more than five reports in a single season, even when he worked the vicious 2005 season. In reviewing that season, he and his colleagues discovered a transient unnamed subtropical storm that formed near the Azores on Oct. 4. They noticed the feature when poring over satellite observations and noted a 58 mph wind gust from an Azores weather station. The hurricane center declared the system a “previously unnoted ... unnamed subtropical storm” the
next April.
The heaviest lifting when authoring reports comes in determining a cyclone’s activity upon landfall. That’s especially challenging for intense storms, which have a tendency to destroy observation equipment. In some cases, the center even ingests data from third-party storm chasers to supplement observations.
Blake said the logistics of having an aircraft sample a storm at landfall can be challenging, and if a storm comes ashore in an area without a dense weather station network — as is often the case outside the U.S. — chasers can offer some valuable numbers.
“It can increase the confidence of our assessment at landfall, (especially if we have) two different data types,” Blake said.
‘Hurricane Man’
Among the most prominent and respected hurricane chasers is Josh Morgerman, who turned his lifelong passion for weather into a profession by crafting his brand as the “Hurricane Man.” He’s penetrated the fiercest of hurricanes and typhoons, standing in the eye of a handful of Category 5s, including Dorian, whose infamous September 2019 onslaught ravaged Grand Bahama and Great Abaco islands. His data is often used in Hurricane Center reports.
“Initially when I started chasing I didn’t collect data,” Morgerman said on a recent Zoom interview. “It didn’t occur to me to do that in the ’90s. I was just an adrenaline junkie.”
But then, he says, he began reading hurricane center reports and reports from other monitoring agencies around the globe — and he noticed how sparse observations in developing countries could make it tough to assess landfall intensity.
“One thing that frustrated me was the lack of ground truth when a cyclone comes ashore — when there isn’t even aircraft reconnaissance,” he said. “When a Category 5 typhoon strikes a remote corner of the Philippines, we think it’s Cat 5 because of satellite intensity estimates . ... But we don’t really know.”
Now, Morgerman’s data makes frequent appearances in hurricane center reports, including that of Hurricane Willa, which struck Mexico’s Sinaloa state in 2018.
“I planted sensors up and down the coast and got a complete data profile of the hurricane’s core — left eyewall, right eyewall and eye,” Morgerman said. “My data played an important role in the post-analysis, and my landfall diagram even appears in the report.”
His data also helped lend credence to the center’s estimate of Hurricane Patricia’s central air pressure during its late October 2016 landfall in western Mexico.
He witnessed firsthand the effects his data and the center’s reports can have when Category 4 Odile struck the Baja Peninsula in 2014. Adjustments were made to the estimated landfall intensity based on his data, which resulted in corresponding changes to federal disaster funding.
‘A total whiteout’
Morgerman’s approach is highly scientific. He works with a geographer to determine his exact location and altitude to calibrate ultra-sensitive barometers. His high-resolution data has captured the effects of strange tornado-like vortices and eddies within hurricane eyes. He also tracks gradients — or the change of air pressure with distance. That value is proportional to wind speed and can signify how intense a storm is.
During the 2020 season, Morgerman found a gradient of 6.4 millibars per nautical mile as high-end Category 2 Hurricane Sally churned ashore in Gulf Shores, Ala.
“I had gradients comparable to what I measured in Rockport, Texas, during Hurricane Harvey (in 2017),” Morgerman said. Harvey was a Category 4. “(Sally’s) gradients were surprisingly intense.”
Equally surprising were the gradients he found in Hurricane Laura — a comparatively meager 4.4 millibars per nautical mile. Morgerman, who’s stormed into more than two dozen major hurricanes and typhoons, said Laura didn’t quite have the “edge” of other Category 4s he’s witnessed — but he was nevertheless impressed by the storm’s catastrophic impact over a large area in southwest Louisiana and beyond.
The greatest gradient he’s encountered was that of Hurricane Dorian.
“It was a total whiteout,” he said, having recorded a change of up to 12.4 millibars per nautical mile. “I might as well have shot a white shower curtain. When all the clouds (and wind) cleared, the cars had blown away.”
After each storm, Morgerman too writes up his own reports. He shares those with the hurricane center.
“The hurricane center took an interest because they saw me tweeting the information,” he recalled. “The reason I send them reports is because I wanted them to know there is some rigor in collecting good-quality data. I can go into the jaws of these things and get that pressure reading in the eye that fills in the missing puzzle piece in post-analysis.”
Even still, there are occasional disagreements between scientists that result from subjective interpretations of what, no pun intended, can be a whirlwind of data.
“It’s a give-and-take with a bunch of qualified scientists,” Blake said. “We can have some passionate opinions.”
Additional reports on 2020’s major hurricanes can be expected in the months ahead.