'Above normal' activity predicted for remainder of 2023 Atlantic hurricane season, NOAA says

The remainder of the 2023 Atlantic hurricane season is expected to be busier than originally anticipated, partly due to warming ocean waters, according to the National Oceanic and Atmospheric Administration.

NOAA forecasters are predicting 21 named storms, of which up to 11 could become hurricanes, compared to a typical yearly average of 14 named storms and seven hurricanes, meteorologists announced during an updated hurricane outlook call on Thursday. The increase in the number of forecast storms is due to record warm water in the Atlantic Ocean, Matt Rosencrans, lead hurricane season outlook forecaster with NOAA's Climate Prediction Center, told reporters.

Five of those expected hurricanes could become major Category 3, 4 or 5 hurricanes on the Saffir-Simpson scale, with winds of 111 miles per hour or greater, Rosencrans said.

So far, the 2023 season has seen five storms, four named and one unnamed. But the climatological peak of hurricane season has not yet begun, which is why activity is relatively quiet at the moment.

The peak date is still about a month away, with tropical activity typically picking up at the end of August and into September, and sometimes lasting into October.

In May, NOAA predicted a "near-normal" season for 2023, despite a developing El Nino event, which typically suppresses hurricane activity by weakening trade winds and pushing warm water back to the east.

El Nino usually results in atmospheric conditions that help to lessen tropical activity during the Atlantic hurricane season, especially in regions like the Western Caribbean and the Gulf of Mexico, Rosencrans said.

But the warm waters in the Atlantic Ocean are counterbalancing the ongoing El Nino, and the changes typically associated with El Nino appear to be emerging a bit later than initially anticipated, Rosencrans said. The June-July sea surface temperature in the main development region of the North Atlantic were the warmest since 1950, he added.

So far, limiting conditions have been slow to develop, and climate scientists are forecasting that the associated impacts that tend to limit tropical cyclone activity may not be in place for much of the remaining hurricane season.

A below-normal wind shear forecast, slightly below-normal Atlantic trade winds and near- or above-normal West African monsoon lower-atmosphere winds were also key factors in shaping this updated seasonal forecast.

On average, the Atlantic hurricane season ends November 30.

"No matter the overall activity, we're urging you to prepare now for the upcoming quarter of the hurricane season, as a single storm could have catastrophic impacts," Rosencrans said.