Updated May 25, 2023 - Energy & Environment

Atlantic hurricane season to feature duel between likely El Niño and hotter Atlantic

Satellite image of Hurricane Ian as it made landfall in southwestern Florida in 2022.

Satellite view of Hurricane Ian as the storm approached Florida on Sept. 28, 2022. Image: NOAA via Getty Images)

The upcoming Atlantic hurricane season, which officially kicks off June 1, is set to feature a tug of war between a developing El Niño in the Pacific, and unusually warm waters throughout the Atlantic, NOAA forecasters say.

Why it matters: The seasonal outlook, released Thursday, helps inform storm planning for the federal, state and local governments.

Zoom in: The NOAA 2023 hurricane season outlook calls for a 40% chance of a near normal hurricane season, and a 30% chance of either a below or above average season.

  • In terms of numbers, the agency calls for 12 to 17 named storms to form, of which 5 to 9 will become hurricanes and 1 to 4 will be "major" storms of Category 3 intensity or greater.
  • This compares to the 30-year average of 14 named storms, 7 hurricanes and 3 major hurricanes.

Between the lines: A developing El Niño in the equatorial tropical Pacific Ocean would typically indicate a below average Atlantic hurricane season, and above average eastern Pacific season, is likely.

  • El Niño events can reduce Atlantic tropical storm and hurricane activity by increasing winds in the upper atmosphere over the tropical Atlantic.
  • Such wind shear can disrupt incipient storms before they can strengthen.
  • However, heading into this summer, sea surface temperatures in the typical hurricane forming regions of the Atlantic along with most other areas are unusually warm for this time of year.
  • That would suggest an unusually active season lies ahead.

What they're saying: For now, NOAA is threading the needle between the two influences, in addition to others.

  • “It’s kind of like a clash between those big factors,” said NOAA hurricane seasonal forecaster Matt Rosencrans at a press conference.
  • He added that the sea surface temperature anomalies are likely to stick around, particularly in the tropical Atlantic, through the summer.

The intrigue: The Atlantic is still in the midst of a largely natural multi-decade upswing in hurricane activity, though human-caused climate change is driving an increase in sea surface temperatures there and around the world.

Threat level: Climate change is already having detectable changes to nature's largest and most powerful storms.

  • A warmer atmosphere can carry more water vapor, which gets wrung out as heavy rains over land. On average, storms are now wetter than they used to be.
  • In addition, increasing ocean and air temperatures are leading to more high-end, major hurricanes, but are not thought to be increasing the total number of storms overall.
  • As was seen with Hurricanes Ida, Michael and Ian in recent years, hurricanes are exhibiting a greater tendency to rapidly intensify, leaping storm categories in short periods of time and potentially catching emergency managers off guard.
  • Also, the magnitude of storms' rapid intensification is increasing in many parts of the world.

Of note: Some studies show that tropical storms and hurricanes are moving more slowly at landfall, related to slackening steering currents, though this is an area of active research. Slow-moving storms have a greater potential to cause inland flooding.

The big picture: Other forecast groups have also been seeking a balance between the potential El Niño and Atlantic sea surface temperatures.

  • The University of Pennsylvania put out a new outlook calling for between 12 and 20 named storms, with a "best guess" of 16.
  • A separate early outlook issued last month from forecasters at Colorado State University projects a slightly below-average Atlantic hurricane season

Yes, but: While the seasonal outlook helps spur storm preparation activities, it provides little to no guidance on where such storms may ultimately strike.

Editor's note: This story has been updated with additional reporting.

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