August In The Atlantic Hurricane Season: Don’t Expect Another Shutout Like 2022, Despite El Niño

T​he 2023 Atlantic hurricane season won't likely be shutout in August as it was last year, despite the potential influence from El Niño.

L​ast August, no tropical storms formed in the Atlantic Basin. That was only the third time since 1950 the entire month of August went without a single tropical storm.

A​ combination of wind shear and dry air teamed up to squelch development in August 2022.

A​ugust is usually one of the most active months. Over the last 30 years, an average August produces three to four storms, one to two of which become hurricanes.

T​hat's because wind shear – typically hostile for tropical cyclones – reaches its seasonal low point in August as ocean water continues warming toward its September-October peak.

By contrast, A​ugust 2021 delivered seven storms, four of which became hurricanes. Among them was Hurricane Ida, which hammered southeast Louisiana at Category 4 intensity near the end of August, then flooded out parts of the Northeast on Sept. 1.

T​his August, El Niño is in play. One of the most shocking things about last August's shutout is that it occurred during a La Niña, the periodic cooling of central Pacific Ocean water near the equator. Usually, La Niña hurricane seasons are very favorable for tropical development.

B​ut that long-lasting La Niña finally disappeared ​and the ocean waters warmed sufficiently that a​n El Niño was declared in early June.

The reason this strip of water far from the Atlantic Basin matters is that it's one of the strongest influences on hurricane season activity.

In El Niño hurricane seasons, stronger shearing winds and sinking air often occur over at least the Caribbean Sea and some adjacent parts of the Atlantic Basin. This tends to limit the number and intensity of storms and hurricanes, especially if the El Niño is stronger, as we investigated in a March article.

H​ere's what past El Niño hurricane seasons have delivered in August: Given that typical setup, we examined the 21 previous El Niño hurricane seasons since 1950.

A​s you can see in the graph below, an El Niño historically delivered about one fewer August storm and about one fewer August hurricane than the average.

D​oes the strength of El Niño matter? The El Niño is now of moderate strength and could gain a bit more intensity by the peak of hurricane season, August through October, according to the latest outlook from NOAA issued in mid-July.

W​hen we parsed out the 10 seasons that had at least a moderate-strength El Niño in place by August, there was little difference in the number of August storms and hurricanes compared to all El Niño seasons.

M​ost of those eventually either curled out over the open North Atlantic or fizzled once they were near or in the Caribbean Sea.

There have been exceptions. Betsy became a tropical storm over the Leeward Islands in late August 1965. It swept through the Bahamas, grazed South Florida, then hammered southeast Louisiana, including New Orleans, as a strong hurricane in September. That all happened despite a strong El Niño.

I​n August 1951, Hurricane Charlie plowed straight through the Caribbean Sea and southern Gulf of Mexico. After it nailed Jamaica, Charlie pummeled Cozumel, Mexico, at Category 4 intensity, then made its final landfall as a Category 3 hurricane near Tampico, Mexico. A moderate El Niño was in place that August.

T​here's a major wild card this August. Despite El Niño, much of the tropical Atlantic Basin is experiencing record-warm ocean temperatures. That includes the so-called main development region from Africa westward, in which many stronger Atlantic hurricanes get their start.

This is important because assuming other factors are equal, the deeper and warmer the ocean water, the stronger a storm or hurricane can become.

T​his warmth we're seeing right now is more typical of the peak of hurricane season, with time for additional warming.

At least some of El Niño's typical influence in the atmosphere could be drowned out by the widespread Atlantic Ocean warmth. That's why seasonal outlooks have trended up as far as the number of storms and hurricanes are concerned.

August may deliver some surprises, relative to both an average hurricane season, and even an El Niño hurricane season.

P​repare for hurricanes, regardless. Typically, 92% of a hurricane season's activity happens from August through the end of the season, according to data compiled by the Colorado State University tropical forecast team.

T​hat means a typical hurricane season after July 31 produces 12 storms, seven of which become hurricanes and three of which become Category 3 or stronger, according to the National Hurricane Center.

R​egardless of factors such as El Niño or record-warm water, it only takes one storm impacting your area to make it an infamous, destructive hurricane season.

The time to be ready is now. Information about hurricane preparedness can be found here.

Jonathan Erdman is a senior meteorologist at weather.com and has been an incurable weather geek since a tornado narrowly missed his childhood home in Wisconsin at age 7. Follow him on X/Twitter, Facebook and Threads.

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