May 26, 2023 - Energy & Environment

Hurricane season wild cards

Data: NOAA OISST; Chart: Erin Davis/Axios Visuals
Data: NOAA OISST; Chart: Erin Davis/Axios Visuals

The outlook for the 2023 Atlantic hurricane season is more notable for its unusual level of uncertainty than for what it actually projects, Andrew writes.

The big picture: The National Oceanic and Atmospheric Administration's latest forecast, which aims to help governments and coastal residents prepare for the season, predicts a rare battle between two powerful climate forces — one of which has its roots in human activities.

Driving the news: The NOAA on Thursday called for a 40% chance of a near- average hurricane season; and a 30% chance of a season that's either below or above average.

Between the lines: The nearly equal probabilities NOAA assigned to each outcome signals a low confidence forecast.

  • The combination of a hotter-than-usual Atlantic Ocean, along with a developing El Niño in the equatorial tropical Pacific Ocean, is a rare combination that is limiting forecast confidence.
  • Typically, a hot Atlantic argues for an above average season. Current temperatures in the tropical Atlantic are comparable to conditions at the same time of year in 2020, which turned out to be the busiest season on record.
  • The hotter than average Atlantic has its roots partly in human-caused climate change, driven mainly by burning fossil fuels such as coal, oil and gas.

Meanwhile... If El Niño develops and strengthens by August or September, it could contribute to stronger-than-normal upper level winds over the tropical Atlantic.

  • This can inhibit the formation of nature's most powerful storms.
  • This rare combination of climate forces provides few, if any, analog hurricane seasons to guide forecasters.
  • The NOAA's forecast essentially bets that a warm Atlantic — and a developing El Niño — will tussle to a draw, or close to it, leading to a near-average season for storm numbers.

Context: The unusually hot Atlantic is not an isolated occurrence.

Our thought bubble: This season's ingredients could come together more frequently in a rapidly warming world, with El Niño and La Niña exerting less of an influence over the Atlantic hurricane season, due to sea surface temperature spikes.

What they're saying: “There's definitely kind of a rare setup for this year. That’s why our probabilities are not 60 or 70 percent,” NOAA lead hurricane seasonal forecaster Matthew Rosencrans said at a news conference.

Yes, but: The uncertainty about how many storms there may be does not reduce the need for storm preparations, since all it takes is one landfalling storm to cause significant damage.

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