Meteorologists who have spent the past few days monitoring the rapid progress of Hurricane Melissa in the Atlantic Ocean, are sounding the alarm about the storm, which is expected to make landfall in Jamaica today as a Category 5 hurricane. The sustained — and increasing — intensity of the storm is remarkable, experts say, and has the characteristics of a historic hurricane.
“When I look at the cloud patterns, I will tell you as a meteorologist and a professional – and as a person – it’s beautiful, but it’s terrifying,” says Virginia-based meteorologist Sean Sublette. “I know what’s under those clouds.”
There are different ways to measure the strength of hurricanes. The first is atmospheric pressure: the lower the pressure, the stronger the storm. Early Tuesday morning, as it approached Jamaica, Melissa measured a minimum pressure of 901 millibars (mb), lower than Hurricane Katrina’s maximum low of 902 mb, and the lowest pressure ever recorded in a hurricane this late in the year, according to CSU meteorologist Philip Klotzbach.
Incredibly, by Tuesday morning, Melissa wasn’t done escalating. At 10 a.m., the National Weather Service issued an update measuring the storm’s pressure at 892 mb. If it makes landfall at this pressure, it would tie with the catastrophic Labor Day hurricane of 1935, which struck Florida, as the most intense hurricane in terms of pressure to make landfall.
“This record has been around for 90 years now,” says Brian McNoldy, senior research associate at the University of Miami’s Rosenstiel School of Marine, Atmospheric and Earth Science. “It would be a big deal if it fell.”
The pressure that drops as a hurricane approaches land, especially around high ground, is “really remarkable,” McNoldy says. “Normally it would start to look like a mountainous island, like Jamaica, and that would interrupt it a little bit and start to weaken it. But actually it’s continuing to intensify right now.”
A second way to measure hurricanes is wind speed; Melissa also surprised meteorologists with how strong it was here, as well as how quickly it intensified. Wind speeds inside Melissa measured just 70 mph Saturday as the storm formed in the Atlantic basin, lower than the 74 mph of the mildest Category 1 storms. However, they had quickly increased to 140 mph (Category 4 force) just 24 hours later. Melissa’s winds continued to intensify Monday and Tuesday. As of 10 a.m. Tuesday, maximum sustained winds were 185 mph.
“It’s extremely rare for a storm to intensify quickly when it’s already very intense,” McNoldy says. “You typically see rapid intensification happening when it’s a tropical storm or Category 1 or 2 hurricane. That’s when it’s very common. But not when the intensity is already at the high end.”
