NOAA predicting ‘extraordinary’ Atlantic hurricane season - The Boston Globe (2024)

“There’s reason to be concerned but not alarmed‚” Ken Graham, director of the National Weather Service, said during a morning press conference.

He emphasized that although this year’s forecast numbers are “above normal,” community preparedness will be the key.

“Yes, it’s the highest number, but it’s about being ready, right? So now’s the time to be prepared,” Graham said.

The average number of named storms in a typical season is 14, with usually two landfalling storms. Last season was above average with 2023 seeing 20 named storms, seven hurricanes and three major hurricanes — roughly in line with what NOAA predicted last year: 12-17 named storms, five to nine hurricanes and one to four major hurricanes.

This season, NOAA administrator Rick Spinrad said, confidence is high. There’s an 85% chance that up to 25 storms will develop.

Lots of warm ocean water and minimal wind shear are what fuel hurricanes, and this year, Graham said, all the right elements are “coming together.”

“We’ve seen a lot of seasons where you have a lot of warm (ocean) temperatures but a situation where there’s too much (wind) shear, but you look at this forecast, it’s all coming together,” Graham said. “...You have all the energy in the ocean, an active African monsoon, so check, check. Don’t expect a whole lot of shear, check. So you really look at all the different patterns and they all come together to make this big forecast.”

Officials point to record-high water temperatures of the Atlantic in recent years as having a measurable impact on tropical storms this season, as in previous years, enough to accelerate already strengthening hurricanes.

“Rapid intensification is a real concern,” Graham said. Every Category 5 storm that made landfall in the US ”were tropical storms or less just three days prior, and several of them didn’t even exist three days prior.”

A Category 5 hurricane is one in which wind speeds reach 156 miles per hour or stronger, according to the Saffir-Simpson Hurricane Wind Scale. Hurricanes designated as Category 3 through 5 are considered major hurricanes.

Climate scientists say most of the record heat is from human-caused climate change of carbon dioxide and methane emissions from the burning of fossil fuels, as well as heat from a natural El Niño, a warming of the central Pacific Ocean that changes global weather patterns.

Spinrad noted that “this season is looking to be an extraordinary one in a number of ways based on our data and models with El Niño and La Niña playing out in a significant role.” Meteorologists said El Niño is slowly phasing out and its opposite, La Niña, the cooling of sea surface temps in the eastern tropical Pacific, is arriving.

An aggressive hurricane season that produced Hurricane Katrina in 2005 was in part due to La Niña paired with rising sea surface temperatures, similar to this year, meteorologists said. With 28 named storms and a record-setting 15 hurricanes where seven made landfall, 2005 remains the most destructive hurricane season on record.

“This year has higher ranges than we had forecast in 2005, with the sea surface temperatures in the main development region (of the Atlantic) being 2 to 3.5 degrees Fahrenheit above normal, the equivalent of what we would see in August and dramatically warmer than 2005 and even 2010,” said Matthew Rosencrans, lead seasonal hurricane forecaster with NOAA.

Spinrad said NOAA’s official Climate Prediction Center forecast “indicates a 77% chance of La Niña (presence) in the August/September/October timeframe (peak hurricane season), leading to weaker trade winds and less vertical wind shear, conducive for storm development.”

Most of the hurricane forecasts — from the United States and Europe — are predicting 20 or more named tropical storms will spin up across the Atlantic Ocean through Nov. 30, when the season ends.

“If warm water continues to trend north, that will increase the chance for storms to track north,” said Dr. Kim Wood, associate professor of hydrology and atmospheric science at the University of Arizona.

Hurricane forecasts are created by looking at such factors as sea surface temperatures, potential for La Niña conditions, jet stream positioning, and wind profiles to determine the likelihood that tropical storms and hurricanes will develop.

“It’s a bit of a roulette game where there are pockets of favorability, including where there is less wind shear and warm sea surface temperatures,” explained Dr. Alex DesRosiers, a hurricane researcher and co-author of the Colorado State University’s seasonal hurricane forecast.

“Another technique we use is called ‘analog years’ where we analyze previous years with similar conditions to compare with our current forecast— they show us a lot of data.”

The main goal of hurricane outlooks is to spread information and awareness so the public can be informed and can plan ahead, especially as record ocean temperatures keep rising and, in turn, strengthen tropical storms into more active hurricanes. Also, these monstrous storms are expected to spin up sooner than average.

“The seasonal hurricane forecast is a reminder that no matter what the forecast is, people should be preparing regardless. Get ready and have an emergency kit and plan ready to go before a storm threatens your area,” DesRosiers said.

That message was emphasized Thursday by NOAA officials, who said many lives are lost each year due to hurricanes.

“We know communities can be devastated from the impacts of hurricanes,” Spinrad said, noting that hurricanes last year claimed many lives and caused $4 billion in damages in the contiguous US.

“The general public needs to prepare the same for every hurricane season, since it just takes one storm near you to make it an active season,” noted Dr. Phil Klotzbach, senior research scientist at CSU.

Will New England be spared?

What this forecast means for New England remains to be seen. The NOAA forecasts typically do not drill down to specific regions of the US. The Globe weather team’s hurricane outlook released May 3 does predict at least one tropical storm will likely make landfall during this season.

Also, the Colorado State University hurricane forecast places a 49% chance for a named storm to impact the area this season.

Countless tropical storms and remnant systems have deluged the region, but the last hurricane to make landfall here was actually Hurricane Bob in August 1991. And since 2000, New England has only seen five actively named storms make landfall — the last one being Tropical Storm Henri in 2021.

New England saw minimal impacts from a downgraded Hurricane Lee in mid-September. Lee ended up as a “post-tropical cyclone” by the time it reached the Northeast. Such a storm loses its tropical characteristics as it moves over cooler water. It did, however, manage to pack a punch with near-hurricane-force winds of 70 miles per hour when it made landfall in Nova Scotia.

‘Cone of uncertainty’ graphic updated

Also on Thursday, NOAA officials announced that the National Hurricane Center will begin using an updated forecast cone graphic (its famous “cone of uncertainty”) around Aug. 15 to better visualize the potential path and impacts of a tropical storm or hurricane this season. They said the new graphic will be used on an “experimental” basis.

“The graphic is powerful because it visualizes impacts in and outside of the cone,” Graham said. The updates to the cone include the addition of storm watches and warnings for impacted areas inland, as well as continuing coastal alerts. Another new feature will be wind risk across inland communities to better communicate overall impacts for people.

“Right from the start, the primary criticism of the cone was that it gave people the wrong impression that it indicated threat— if you’re inside of the cone you’re in trouble, and if you’re outside of it, you’re fine. But that is not at all what it is designed to indicate and is a dangerous misinterpretation,” said Brian McNoldy, senior research associate and tropical cyclone expert at the University of Miami’s Rosenstiel School of Marine, Atmospheric, and Earth Science.

The graphic has undergone only a handful of iterations since it was first introduced on July 14, 2002.

Ken Mahan can be reached at ken.mahan@globe.com. Follow him on Instagram @kenmahantheweatherman. Marianne Mizera can be reached at marianne.mizera@globe.com. Follow her @MareMizera.