Atlantic ocean hurricane season may be more eventful than normal, NOAA says

Continuing warm temperatures in the Atlantic Ocean and lighter winds are expected to help contribute to a busier than normal hurricane season this year federal officials said Thursday, boosting their prediction for the number of named storms and hurricanes.

Seasonal forecasters had expected the El Niño in the Pacific Ocean to increase vertical wind shear over the Atlantic and help shear off the tops of budding hurricanes this season, but so far those conditions haven't come to pass, the National Oceanographic and Atmospheric Administration said.

The updated seasonal outlook now calls for 14 to 21 named storms, six to 11 hurricanes and between two and five major hurricanes. That includes the five storms that have already formed this year.

What to know about hurricane season 2023Forecasts, definitions, and preparation.

How many storms occur in an average season?

Fourteen named storms, of which seven become hurricanes, including three major hurricanes.

How many storms have formed this year?

So far this year, the Atlantic has seen three named tropical storms – Arlene, Bret, and Cindy – and Hurricane Don. The fifth was an unnamed storm that formed in January. The National Hurricane Center discovered in an after-storm analysis that it had strengthened enough to be considered a tropical storm.

Why did NOAA bump up its forecast?

The El Niño conditions that could influence Atlantic storms have been slower to develop than expected and climate scientists say they may not be in place for much of the remaining hurricane season, which ends November 30, NOAA said Thursday.

With near-record warm seas, below-normal wind shear, below-normal trade winds and a near-normal or above-normal monsoon season in West Africa, many of the ingredients needed for storm formation are in place.

Considering all the factors in play, "the updated outlook calls for more activity, so we urge everyone to prepare now for the continuing season,” said Matthew Rosencrans, the Climate Prediction Center's lead hurricane season forecaster.

NOAA's isn't the only seasonal outlook to predict above-normal activity. The tropical meteorology team at Colorado State University also increased its outlook slightly last week, calling for a total of 18 named storms, with nine hurricanes.

What's the El Niño forecast?

NOAA also updated its El Niño outlook Thursday, saying forecasters are more confident in a "strong" El Niño event this winter. A strong El Niño doesn't necessarily mean that strong impacts are expected to the nation's winter, the outlook stated.

The agency sees a greater than 95% chance of El Niño continuing through the winter and into February 2024.

Infographic: An inside look at the birth and power of hurricanes