The United States’ National Oceanic and Atmospheric Administration (NOAA) has maintained its forecast for a below-normal 2026 Atlantic hurricane season, citing the growing influence of El Niño as the main factor expected to suppress tropical cyclone activity.

In an updated outlook released on Thursday, NOAA said the Atlantic is now expected to produce between seven and 13 named storms during the June 1 to November 30 hurricane season. 

Of those, two to six are forecast to become hurricanes, including up to two major hurricanes with winds of at least 111 mph.

The forecast includes Tropical Storms Arthur and Bertha, the only two named storms to form so far this season.

NOAA said there is a 75 per cent chance the season will finish below normal, a 20 per cent chance of near-normal activity and just a five per cent chance of an above-normal season. 

The updated outlook is largely unchanged from the agency’s initial forecast issued in May.

The NOAA noted a typical Atlantic hurricane season produces 14 named storms, including seven hurricanes and three major hurricanes.

Both Arthur and Bertha formed in the Gulf before making landfall in Louisiana. Arthur brought record rainfall to parts of the state and spawned tornadoes along the Gulf Coast.

NOAA National Weather Service Director Ken Graham said the impacts of tropical systems extend beyond their wind speeds.

“Inland rainfall is a major cause of damage from tropical storms and hurricanes, as Arthur demonstrated. That’s why it’s important to prepare for every storm that’s projected to impact your area, even if it never reaches hurricane strength.”

Forecasters said the development of El Niño in June has become the dominant factor shaping this year’s Atlantic season. The climate pattern increases wind shear over the Atlantic, making it more difficult for tropical systems to develop or intensify.

Matt Rosencrans, NOAA’s lead hurricane season forecaster, said the strengthening El Niño is expected to continue limiting storm activity in the basin.

While Atlantic activity is forecast to remain subdued, NOAA said El Niño is having the opposite effect in the Pacific.

The agency continues to predict an above-average Eastern Pacific hurricane season, with 15 to 22 named storms expected. Seven named storms have already formed there, including two hurricanes, one of which reached major hurricane strength.

An above-normal season is also forecast for the Central Pacific, where five to 13 named storms and tropical depressions are expected.