Rapid intensification? Hurricane forecasters say Erin's winds could skyrocket.
This phenomenon can cause a tropical storm to escalate into a hurricane or a hurricane to jump one or more categories on the Saffir-Simpson scale in less than a day.
An early Aug. 14 forecast from the National Hurricane Center said that Erin was forecast to undergo rapid intensification, but based on new data, a later forecast called for "steady" intensification over the next few days.
"Erin is moving into an environment with very warm water temperatures, and it's not going to exit that environment for at least 5 or 6 days," said Houston-based meteorologist Matt Lanza in his Substack The Eyewall. "Erin should begin to tap into this environment over the next couple days, and it's possible that we see a burst of rapid intensification at some point."
Regardless, the environment ahead looks ripe for Erin to become a powerful major (Category 3 or stronger) hurricane this weekend, and the storm is forecast to be nearing Category 4 strength as it turns into the western Atlantic early next week, noted WPLG hurricane specialist Michael Lowry in an Aug. 14 Substack post.
Though not currently thought to be direct threat to land, Erin's waves are forecast to batter the East Coast with high surf and the threat of dangerous rip currents for beachgoers.
What is rapid intensification? Why is it dangerous?
Rapid intensification is a process in which a storm undergoes accelerated growth: The phenomenon is typically defined to be a tropical cyclone (whether a tropical storm or hurricane) intensifying by at least 35 mph in a 24-hour period.
As of the 11 a.m. ET advisory from the hurricane center, a rise of 30 mph in 24 hours is expected.
Whatever happens with Erin, rapidly intensifying tropical storms and hurricanes are especially dangerous because they can give the public less time to prepare and often catch people off guard, AccuWeather said. "Predicting a storm's peak intensity and its intensity at landfall is one of the most difficult aspects of weather forecasting, and a rapidly intensifying hurricane adds tremendously to that challenge," according to AccuWeather.
What causes rapid intensification?
"Rapid intensification occurs when a tropical storm or hurricane encounters an extremely conducive environment," Colorado State University hurricane researcher Phil Klotzbach said. "Typically, this environment consists of very warm water, low vertical wind shear and high levels of midlevel moisture."
Such sudden spikes have been the hallmark of history's most fearsome hurricanes, Ken Graham, former director of the hurricane center and now director of the National Weather Service, told USA TODAY in 2022. Out of the nine hurricanes with winds of 150 mph or greater that struck the U.S. mainland over 103 years, all but one saw the explosion of force and power known as rapid intensification.
What is the Saffir-Simpson scale?
Hurricanes are measured by wind speed, with the higher categories on the Saffir-Simpson scale corresponding to more intense storms. Here's the full scale:
Category / Sustained Winds:
1: 74-95 mph
2: 96-110 mph
3: 111-129 mph
4: 130-156 mph
5: 157 mph or higher
This article originally appeared on USA TODAY: Hurricane 'rapid intensification' worries return with Erin
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