Early forecasts suggest that Idalia could become a major Category 3 storm before reaching Florida.
That boost in intensity could happen quickly, fueled by “wildly hot” conditions in the Gulf of Mexico, said Jill Trepanier, an associate professor and climate scientist at Louisiana State University.
Idalia is also expected to move through an area with low wind shear, which describes the change in speed and direction of winds at different atmospheric heights. Strong wind shear can tear storms apart before they gather strength, whereas areas with weaker wind shear can set the stage for rapid intensification.
“Idalia is kind of passing through the wrong spot, in a manner of speaking — the spot that would make it worse for those in Florida,” Trepanier said.
The term “rapid intensification” describes an increase in sustained wind speeds of at least 35 mph over the course of a single 24-hour period, according to the National Hurricane Center.
Conditions that jumpstart rapid intensification are typically found over the ocean, where warm waters and moisture in the atmosphere provide the necessary energy to fuel big storms.
“The hurricane gets fed by the flow of heat from the ocean to the atmosphere,” said Robert Weisberg, an emeritus professor of physical oceanography at the University of South Florida.
The combination of warm waters, low wind shear and high levels of moisture in the atmosphere means a tropical storm can turn into a Category 3 hurricane in just a short amount of time, Weisberg said.
But while scientists know the ingredients that make rapid intensification likely, the precise catalyst is not yet well understood.
Part of the reason that rapid intensification is seemingly on the rise is that satellite technology has improved scientists’ ability to track big storms, Trepanier said.
“Pre-1980, our ability to know what was happening from one hour to the next was extremely limited,” she said. “We may only have known in broad strokes what the intensity was.”
Climate change may also be playing a role, Trepanier said, but the exact mechanisms are hard to tease out at the moment. Studies have shown that global warming may not be increasing the overall number of hurricanes, but that a warmer climate is increasing storm intensity when they do occur.
Trepanier said climate change is likely having an impact, but understanding the precise effect of global warming on rapid intensification needs more research.
“There might be a storm that has all of the signatures that should lead to rapid intensification, but then it doesn’t,” Trepanier said. “And then there are some where we aren’t sure exactly why it rapidly intensified. So the climate signature is harder for us to identify at this time.”
But whether and how a storm intensifies, the underlying message for people along the hurricane’s path remains the same: Take proper precautions and heed the warnings of local officials.
“Regardless of why, it’s still happening,” Trepanier said of efforts to understand rapid intensification. “We know it can happen, and we’ve seen rapid intensification occurring close to the coast, so it should not be ignored.”
Denise Chow is a reporter for NBC News Science focused on general science and climate change.
Category: Science
Source: NBC Science
