NOAA forecasts a near average 2023 Atlantic hurricane season
Published Date: 5/25/2023

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.