Sea Surface Temperature Anomalies measured 4.4.24

Colorado State Predicts “Extremely Active” 2024 Atlantic Hurricane Season

Colorado State University, which has one of the best reputations in seasonal hurricane forecasting, predicted on April 4 that the 2024 Atlantic Season will be “extremely active.” Compared to the average for 30 years from 1991 to 2020, the metrics suggest tropical activity could increase by 50% or more. Below are some of CSU’s key predictions.

MetricCSU April Forecast for 2024Average for 1991-2020 % Increase
Named Storms2314.453%
Hurricanes117.253%
Major Hurricanes53.256%
Accumulated Cyclone Energy*1257371%
*West of 60 degrees longitude (Caribbean, Gulf, Western Atlantic, US East Coast)

2023 had 20 named Atlantic storms. That ranked fourth for the most-named storms in a year since 1950. If CSU predictions are accurate, this year will be even worse.

Basis for Forecast: Warm Waters, Less Wind Shear

According to CSU, when waters in the eastern and central tropical and subtropical Atlantic are much warmer than normal in the spring, it tends to weaken winds blowing across the tropical Atlantic. These conditions will likely lead to a continuation of well above-average water temperatures.

And a very warm Atlantic favors an above-average season, since a hurricane’s fuel source is warm ocean water. In addition, a warm Atlantic leads to lower atmospheric pressure and a more unstable atmosphere. Both conditions favor hurricanes.

The graph below from NOAA shows just how much warmer than normal sea surface temperatures were yesterday.

As of yesterday, sea surface temperatures around the world averaged 1 to 4 degrees centigrade higher than normal for this time of year. Four degrees centigrade equals 7.2 degrees Fahrenheit.

Confidence Level

Given the combined signals favorable to hurricane formation, CSU has higher-than-normal confidence for an April outlook that the 2024 Atlantic hurricane season will be very active.

This is the highest prediction for hurricanes that CSU has ever issued with their April outlook. 

CSU

The CSU team will issue additional forecast updates on June 11, July 9 and Aug. 6.

New Metric More Accurate

“Accumulated Cyclone Energy (ACE) generated west of 60 degrees west” is a new metric, introduced by CSU this year. It correlates better with landfalling storms in the Atlantic basin than basin-wide ACE. That’s because virtually all hurricane-prone landmasses in the Atlantic Ocean are located west of 60 degrees west.

Landfall Predictions

The CSU report also includes the probability of a major hurricane making landfall:

  • 62% for the entire U.S. coastline (average from 1880–2020 is 43%).
  • 34% for the U.S. East Coast, including the Florida peninsula (average from 1880–2020 is 21%).
  • 42% for the Gulf Coast from the Florida panhandle westward to Brownsville (average from 1880–2020 is 27%).
  • 66% for the Caribbean (average from 1880–2020 is 47%).

Data wonks can read CSU’s full 44-page report here.

Consistent with Other Seasonal Forecasts

Forecasters on both sides of the Atlantic have predicted an extremely active hurricane season since January. Adjectives have ranged from “supercharged” to “grim” and “blockbuster.”

The National Hurricane Center usually issues its seasonal outlook a little later in the season.

As always, researchers caution coastal residents to take proper precautions. It takes only one storm near you to make this an active season for you.

For more information about climate, hurricanes, and hurricane preparation, visit the National Hurricane Center.

Posted by Bob Rehak on 4/5/24

2411 Days since Hurricane Harvey