Hurricane forecasters now predict ‘above-average’ season. Blame a hot Atlantic.

When forecasters in April first predicted this year’s hurricane season would be slightly below average, they added an important asterisk.

There was uncertainty, they said, between two conflicting meteorological factors: A strong El Niño, when the jet stream could weaken stronger hurricanes, and an “anomalously warm” Atlantic Ocean, which can fuel hurricanes.

Three months later, the potential victor of that tug-of-war is becoming more clear — and forecasters on Colorado State University’s renowned tropical weather and climate research team are adjusting their hurricane season outlook accordingly.

Their updated hurricane season outlook, released Thursday, now calls for an “above-average” season with 18 named storms, of which nine will become hurricanes and four will reach major hurricane strength (with sustained winds of 111 miles per hour or higher). That’s five more named storms — and two more major hurricanes — than first predicted.

The reason for more predicted storms? The “extreme anomalous warmth” in the Atlantic Ocean. Translation: It’s piping hot out there, with plenty of tropical fuel standing at the ready.

Across the Atlantic, most areas are running about 1 degree Celsius above normal. That may not seem like much, but it makes a huge difference in the tropics, Philip Klotzbach, a meteorologist with the university, said in an interview with the Tampa Bay Times.

“That is the big reason why we upped the numbers is just because we’re dealing with an Atlantic that’s as warm in early July as it should be in early August,” Klotzbach said. “So we’re running like a month ahead of schedule, which is not great.”

Klotzbach anticipates sea surface temperatures will warm over the next couple of months, as they normally would. But just how fast is the question. Temperatures could continue to rise faster than normal, or mellow out to a more average rate, he said. Only time will tell.

Why the new prediction?

A few other factors led to the increase in the forecast, Klotzbach said.

Presently, the atmosphere hasn’t responded like forecasters would expect during an El Niño year. Typically, the natural climate phenomenon would produce an abundant amount of wind shear, especially in the Caribbean, Klotzbach said. But not this year.

In June, forecasters observed some of the lowest amounts of shear on record in the Caribbean, Klotzbach said. That is changing, however. Klotzbach said he’d be shocked if July shear was a record low, but the shear is not the screaming winds forecasters expect.

Another reason for the increase in forecast: two oddball tropical storms that popped up in June — Tropical Storm Bret and Tropical Storm Cindy. The two named storms were the first to form simultaneously in the Atlantic in over half a century, according to Klotzbach. The 18 named storms predicted now include the four storms that have already formed this year.

Normally, a storm or two forming in June would not influence a forecast, Klotzbach said. However, early season activity in the deep tropics is a different (exceedingly rare) story. The formation of Atlantic storms in June and July typically, but not always, lends itself to a busier season, Klotzbach said.

Regardless of the specific number of storms predicted, meteorologists are reminding the public that it just takes one hurricane in your area to make it an active season. There’s always a level of uncertainty in every forecast, and you should prepare for hurricanes every season.

In May, the National Oceanic and Atmospheric Administration predicted a near-normal hurricane season — 12 to 17 named storms, of which five to nine will become hurricanes and one to four will reach major hurricane strength. The university’s latest forecast is nearly identical to the higher end prediction from the administration.

The updated forecast comes the same week that the Earth hit an unofficial record high temperature. With climate change, storms are expected to become stronger and even wetter, as the globe warms and atmospheric moisture increases, according to NOAA.

Historically, there have been years when El Niño has dominated the Atlantic and sea surface temperatures have been moderate. Or years when a La Niña or neutral year was in place, combined with a warm Atlantic. But forecasters have yet to see a year quite like 2023 before.

Klotzbach said there has never been a recorded year with such balmy sea surface temperatures coupled with an El Niño.

“We’re definitely in uncharted territory in terms of the extremely warm Atlantic combined with the El Niño,” Klotzbach said.