Atlantic hurricane season looks ‘very, very busy’, all ingredients line up

The tropical Atlantic is likely to serve up a heady count of 11 hurricanes, of which five will hit major hurricane status, Colorado State University’s Tropical Weather & Climate Research department said in what it called its most severe first look at a hurricane season ever. 

“We are forecasting a very, very busy hurricane season in 2024,” the report's chief author Philip Klotzbach said in announcing the forecast to the National Tropical Weather Conference. 

The full range of forecasts are all 50 - 75% above the 30-year average, including a 71% overshoot versus average for the key metric of accumulated cyclone energy (ACE) which captures the frequency, strength and duration of named storms across the Atlantic and Gulf. 

“This is the highest April forecast that we’ve put out,” Klotzbach said. But the final forecast is still below all of the model readings CSU used in its construction. “With this early lead time we need to be a little bit careful,” he said of the final reading. 

A lot of factors look set to go very wrong: El Niño is weak and fading fast, Atlantic surface temperatures are “extremely warm,” and the Atlantic Meridional Mode looks set to toss in a lot of storm-supportive conditions. 

El Niño, creator of upper-level winds that generate storm-shredding wind shear in the Atlantic, had once been hoped for as a storm stopper again after having offered some help in 2023. 

“Right now, we still have that El Niño, but really it is truly skin deep,” Klotzbach said, citing below-surface Pacific water temperatures set to flip the scales on the ENSO cycle. 

“What we are likely to see in the next few months is a quick transition, I think, to neutral and probably La Niña,” he said. The odds of a helpful El Niño from August on are “very, very low”.

With less protective wind shear likely later in the season, Atlantic surface water temps are freer to do their worst. Current temps are already record for March/April and, even if they grew at the slowest pace on record, would still render a top five season reading by storm season peak, Klotzbach warned. 

“This is the optimal pattern for a busy hurricane season,” Klotzbach said. 

If that weren't enough, Klotzbach adds in a positive phase for the Atlantic Meridional Mode, a contrasting measure of conditions in the northern and southern Atlantic, providing storm-supportive wind patterns, putting moisture into early development areas and still more. 

Madden-Julian Oscillation (MJO) patterns aren't fully visible yet, but could yet add another punch in the onslaught, Klotzbach told conference participants. 

For the record:  CSU forecasts 23 named storms, 11 hurricanes over 45 hurricane days, five major hurricanes and ACE of 210. 

US landfalls from major hurricanes are more likely than not. CSU gives a 62% chance to a landfall anywhere on the US coastline versus the 43% 140-yar average. 

The Gulf coast is at greater risk than the Atlantic coast. The Gulf is given a 42% chance of landfall (vs 27% average) versus a 34% chance on the east coast (21% average). 

But April is distant from the mid-August start to the active portion of the season, Klotzbach reminded. The June forecast brings a major increase in quality, he noted. 

“Stay tuned for further updates, because a lot can change,” Klotzbach reiterated.

Did you get value from this story?  Sign up to our free daily newsletters and get stories like this sent straight to your inbox.