NOAA revises new ‘average’ hurricane season stats
There’s a new normal when it comes to hurricane season, and based on decades of data the National Oceanic and Atmospheric Administration has revised upward its statistics for what an average hurricane season is in the Atlantic.
According to a release today from NOAA, between 1981 and 2010, a typical season in the Atlantic included 12 named storms, six hurricanes, and three major hurricanes. But between 1991 and 2020, the yearly average was 14 named storms, seven hurricanes, and three major hurricanes.
Given the newer data, and effective this season, the Climate Prediction Center will use those revised stats as the new standard for gauging what a typical season is in the Atlantic.
Something worth pointing out in these numbers is what constitutes a major hurricane. Major hurricane is the title objectively given to any storm reaching at least Category 3 strength.
This is the case even if it stays a “fish storm” and brings no direct impacts to land. The title of major hurricane is never applied for record-keeping purposes subjectively. For example, a strong category 2 hurricane with lots of land impacts might be considered a big and bad storm and much worse than a “fish storm” that stays out to sea. But if that storm never reaches at least Category 3 status, it is not technically considered a major hurricane for statistical records.
In today’s release, NOAA attributed the uptick in the storm season average to a few important points: Improved tracking technology, climate change, and an oceanic influence called the Atlantic Multidecadal Oscillation (often simply referred to as AMO).
The improvement in technology is apparent to anyone who has watched a television weathercast during hurricane season. It is easy to see with higher-resolution data monitored by top-notch satellites launched in years past what a better view we have of the tropics now than ever before.
Remember in the days long before the dawn of satellites, storms could only be identified crudely like when they passed ships in the ocean or simply hit land. The improvement in technology today allows forecasters to identify storms that in a different generation may have gone undetected.
The role of climate change, specifically with the warming trend of the world’s oceans is an apparent link worth studying. Hurricanes require warm water to form; they can’t do so without it. Warmer water temperatures persisting for a longer stretch of the year than in decades past allows more available fuel for storms to form and persist.
You can learn more on the latest research into the potential connections between climate change and hurricanes from NOAA here.
Though not tied as tightly to climate change, the variation of the Atlantic Multidecadal Oscillation is also a point to consider. The AMO is a naturally occurring phase in ocean temperatures, but with ranges that can last more than 20 years. According to NOAA, there’s evidence of the AMO being present for about the last 1,000 years.
The current phase we’ve been in for some time, at least since the 1990s, has been positive meaning the phase where water temperatures in the North Atlantic trend warmer. (On the flip side, a negative AMO phase is when those same water temperatures end up cooler).
Read the entire release from NOAA here.