By several metrics, meteorologists knew that Hurricane Melissa was one of the strongest hurricanes that we have ever witnessed in the Atlantic basin. However, a new assessment of data by scientists at the U.S. National Science Foundation National Center for Atmospheric Research revealed that a wind gust of 252 miles per hour was captured by a dropsonde within the storm. That would make it the strongest hurricane or tropical cyclone wind value ever recorded by a dropsonde. Let’s explore this stunning development.
What Is A Dropsonde?
An NSF NCAR press release noted, “Dropsondes are small cylindrical devices that are used by organizations like NOAA to collect valuable information during extreme weather events like hurricanes or atmospheric rivers. As they fall to the surface under a small parachute, dropsonde sensors gather information that helps shape forecasts and inform communities of approaching hazards.” They were developed at NSF NCAR in Boulder, Colorado over 50 years ago and continue to evolve.
Was It The Strongest Hurricane Wind Ever Recorded?
As it became apparent to National Hurricane Center meteorologists that a 252 miles per hour wind gust had been measured in one of the Hurricane Melissa deployments, they knew that this was a potential record, but it needed verification. That’s why they sent the data to NSF NCAR. Even before this process took place, hurricane expert and hurricane hunter Andy Hazleton had signaled this possibility as the storm was impacting the Caribbean region. On October 28, he posted on Facebook, “I couldn’t believe the 113 m/s (250 mph) wind value that I saw on my screen processing this sonde in Melissa today. It literally went off the scale.” Hazleton said in another post later, “I usually set my axis limit to 100 m/s (about 224 mph) and only in the most extreme cases (like Beryl) has it ever even gotten close to that. In this case 100 m/s wasn’t nearly enough.”
Hazleton is an experienced hurricane hunter and an expert at the University of Miami. He was stunned by what he was seeing. He went on to say, “I knew it was likely to have some extreme low-level winds as it rotated into the eastern eyewall, but I didn’t imagine over 250 mph just 250 meters above the surface.” These numbers are why so many of us were very concerned about the fate of Jamaica. We literally witnessed something that nobody has experienced in a hurricane.
Holger Vömel is an NSF NCAR senior scientist with the Dropsonde Program. He reflected, “NOAA looped us in when they saw the high wind speed and asked, ‘Are these numbers any good?’” He further added, “They have pilots and researchers literally putting their lives on the line to get these measurements. They’re the heroes, and it’s a privilege we get to play a role in making sure the measurements they acquire are accurate.” To verify the reading in Hurricane Melissa, Vömel and his colleagues at NSF NCAR used a software program called Aspen. The program performed a quality control analysis to make sure the data were consistent with the laws of physics and tropical meteorology understanding. They also made sure there were no gaps in the dataset that could cause erroneous interpretations.
How Does This Measurement Compare To Others?
NSF NCAR confirmed that the measurement was credible. How does a 252 miles per hour wind gust compare to other extreme storms? According to NSF NCAR, “Hurricane Melissa’s 252 mph wind gust surpassed the previous record from Typhoon Megi over the Western Pacific in 2010, where a dropsonde measured wind gusts of 248 mph.” Western Pacific supertyphoons tend to be the strongest tropical cyclones on Earth. Hurricane Melissa, as I wrote in previous discussions, had the look and intensity of the strongest storms observed in the Pacific Basin. It made a direct hit on Jamaica.
The Value Of Data And Federal Personnel
Throughout Hurricane Melissa NOAA and other federal personnel continued to work even as the government remained shutdown. Their diligence, patriotism and pursuit of data are greatly appreciated. Speaking of data, it is critical to have information about moisture, temperature, wind, and pressure inside a hurricane. Dropsondes are vital workhorses and collect data 2-4 times per second as they fall to the surface of the ocean. NSF NCAR reminded us, “In the case of Melissa, the powerful winds and storm surge went on to inflict catastrophic damage on Jamaica, Haiti, and other Caribbean nations, killing close to 100 people. The toll would almost certainly have been even more grim if the storm had not been well forecasted.” Data collected by hurricane hunters using dropsondes made those forecasts better.
