Hurricane Melissa set another extraordinary record: A 252 mph wind gust

A staggering new observation of Hurricane Melissa was confirmed this week: As the powerful storm was preparing to hit Jamaica in late October, a dropsonde – a probe launched out of the belly of a Hurricane Hunters aircraft – logged a 252 mph wind gust, the National Center for Atmospheric Research announced.

The value is exceptional; it’s the highest wind gust ever recorded from a dropsonde. The measurement, taken at 820 feet above the ground, exceeds the previous record taken from Typhoon Megi over the Western Pacific in 2010, where a dropsonde measured wind gusts of 248 mph.

Even though the Hurricane Hunters from the National Oceanic and Atmospheric Administration had access to the data minutes after dropping the sonde (instrument canister) from the aircraft, the data had to be reviewed before becoming an official record, and the agency reached out to specialists at the National Science Foundation’s National Center for Environmental Research for help verifying, according to the announcement Wednesday.

In 2005, an even stronger wind gust was recorded by a dropsonde in Hurricane Katrina, but it was later ruled to be a false observation.

When the Melissa probe was launched, the 252 mph reading was literally off the charts. The meteorologist on board the Hurricane Hunters flight collecting the data had set up his visualization software so the wind axis had a maximum of 100 meters per second, or 223.7 mph.

“I didn’t imagine over 250 mph just 250 meters above the surface,” tweeted Andy Hazleton, the research scientist onboard the Hurricane Hunters flight.

At the time, Melissa was listed as a 185 mph, Category 5 hurricane, and it was just a couple hours from making a record-setting landfall in southwestern Jamaica.

But the 252 mph dropsonde reading indicates that surface winds may have exceeded the 185 mph estimate made at the time of landfall. Now, scientists at the National Hurricane Center are conducting “reanalysis,” poring over hordes of data. There’s a chance they further upgrade Melissa to a 190 mph storm in postseason analysis. The damage in the eyewall zone rivaled what has been seen with EF4 tornadoes on the Enhanced Fujita scale.

At the time of landfall, Melissa’s 185 mph winds tied the record for the strongest winds at landfall in the Atlantic Ocean. Two storms, the Labor Day Hurricane of 1935 and Hurricane Dorian of 2019 hold that spot as well.

By all accounts, Melissa was a storm of another league, rivaling the most intense tropical cyclones ever observed worldwide – and potentially setting numerous records.

The storm also preliminarily set an informal record for the most eyewall lightning observed by satellite, with nearly 700 flashes per minute – 11 per second – before landfall. Most of the air in hurricanes is moving horizontally rather than vertically, so the majority don’t produce much lightning. When an EEL, or Enveloped Eyewall Lightning, signature develops (a ring of lightning around the eye), it’s a sign of an extremely intense and/or further strengthening storm.

Melissa also had an air pressure of 892 millibars at landfall, tying as the strongest landfalling Atlantic hurricane since the 1935 Labor Day storm. Average sea-level air pressure is 1,015 millibars, meaning Melissa was essentially missing more than 12% of the air from its middle. That missing air created a void of sorts that induced a vacuum effect – and, in turn, pulled in inconceivably strong winds.

The winds were so strong that they tossed cars, demolished cement and concrete buildings, and even blasted paint off some vehicles. That’s according to storm chaser Josh Morgerman, who was in Jamaica in Crawford, St. Elizabeth Parish. In a report of his experience, he described the wind damage as “spectacular.”

That gust also represents the second-strongest ever directly measured globally. On April 10, 1996, Cyclone Olivia was moving through Barrow Island, Australia. At 10:55 a.m. local time, a privately operated anemometer positioned 33 feet above the ground reported a 3-second wind gust of 254 mph.

Australia’s Bureau of Meteorology didn’t own the weather station, and it didn’t conduct an investigation. Fortunately, the World Meteorological Organization did investigate, but it took 14 years to certify the data. That finally happened in 2010.

Other extreme wind gusts, namely from tornadoes, have only been inferred from damage or mobile Doppler radar estimates. It’s believed that the most extreme tornadoes yield winds in the 300 to 320 mph range.