Busy season: NOAA boosts Atlantic hurricane forecast

The National Oceanic and Atmospheric Administration released an updated hurricane season outlook Thursday morning that now speaks of a high likelihood of an above-average hurricane season. The midseason update reflects a dramatic shift in NOAA’s thinking as the agency joins a number of others in expecting a busy season.

Last week, Colorado State University shared its updated outlook, projecting a total of 18 named storms, including the five that have already formed in the open Atlantic. It says the United States has a nearly 50-50 shot at being hit by a major hurricane, rated Category 3 or higher. AccuWeather also nudged its forecast upward.

Hurricane season, which officially runs from June 1 to Nov. 30 and on average peaks around Sept. 15, traditionally does not perk up until mid- to late August. The season to date has featured four named storms. And an unnamed subtropical storm spun up hundreds of miles off the East Coast in mid-January.

Forecasts are highlighting the potential for a season similar to last year’s. Here are NOAA’s latest projections:

■ 14 to 21 named storms vs. the 12 to 17 named storms predicted in late May. This includes the four tropical and subtropical storms that have formed, as well as Hurricane Don in July.

■ 6 to 11 hurricanes, as opposed to the May prediction of 5 to 9

■ 2 to 5 major hurricanes, boosted from 1 to 4.

The Hurricane National Center also now estimates a 60 percent chance of an above-average season — double the predicted odds in May. It also says there is a 25 percent chance of a near-normal season. It puts the odds of a below-average season at only 15 percent.

At present, only the European Center for Medium-Range Weather Forecasting, which oversees the operation of the “Euro” model, paints a picture of a near-average season. Its analysis suggests that 8.5 more named storms are likely.

Regardless, there is a growing cause for concern, as noted by the forecasters behind NOAA’s outlook.

“During active years, there’s a doubling in the chance of a hurricane hitting the East Coast of the U.S. compared to an average or below-average season,” said Matthew Rosencrans, a meteorologist and the director of NOAA’s Climate Test Bed, at a news conference Thursday.

What are the key drivers?

Meteorologists tasked with predicting how the season will play out have been juggling two deeply conflicting signals: record-high Atlantic sea-surface temperatures and a strong El Niño.

High sea-surface temperatures are crucial in helping spawn and intensify hurricanes. This year, the waters are red-hot and reaching records.

“One of the local conditions in the Atlantic that we monitor is the sea-surface temperature,” Rosencrans said. “The June and July sea-surface temperatures in the Main Development Region were the warmest since 1950, about [2.2] degrees above normal.”

He said the formation in June of Bret and Cindy in the “Main Development Region” — the tropical zone between the eastern edge of the Caribbean Sea and western Africa — probably was highly influenced by the hot seas.

“Tropical development in the deep tropics in June or July is usually a harbinger of a more active season,” he said.

The water temperatures will raise the odds of rapid intensification of the storms that do form, posing the danger of big lurches in strength in any potentially landfalling hurricane.

Working against a busy hurricane season is the ongoing El Niño weather pattern. El Niño, which begins as a warming of water temperatures in the eastern tropical Pacific, results in sinking air and hostile upper-level winds over the Atlantic. The nascent El Niño isn’t going away any time soon.

“Odds are in excess of 95 percent that the ongoing El Niño will continue into autumn,” Rosencrans said.

However, his team expects a delayed start to the arrival of En Niño-esque conditions — the same ones usually inhibitive of an above-average hurricane season. With El Niño’s true fingerprint taking a while to show up, the exceptionally warm ocean waters may help kick things into unimpeded overdrive.

“Changes of El Niño appear to be emerging later than expected,” Rosencrans said. “If those changes move in quickly, then activity could be [near the] lower end of our predicted ranges.”

In predicting seasonal hurricane activity, forecasters also consider the Saharan air layer, a stretch of hot, dry and sandy air that wafts over the Atlantic and suppresses storm growth.

“Saharan air outbreaks do peak in June and July, and then fade off in area and intensity as the season goes on,” Rosencrans said, suggesting that this phenomenon will increasingly become less of an impediment to storms.

An active West African monsoon, which provides a source of moisture and disturbances that can become the seeds for hurricanes, also could elevate storm activity.

“During 2023, the West African monsoon rains have been robust, but the winds have been near normal, giving a bit of a mixed signal,” Rosencrans said.

The bottom line

NOAA is exhibiting confidence that the high sea-surface temperatures will supersede the effects of El Niño, favoring a busy season.

Irrespective of how many storms do spin up, it only takes one hitting a populated zone to leave a mark.

“Landfalls are only predictable up to about one week from a storm reaching a coastline,” Rosencrans said. “People should be busy preparing for the storms that this forecast implies.”