NOAA now forecasts 60% chance 2023 hurricane activity above normal

The US weather service NOAA has effectively doubled its forecast outlook for activity in the 2023 Atlantic hurricane season, now predicting a 60% chance of an above normal season, double its 30% prediction from back in May.

NOAA, like all other forecasters, has increased the number of tropical storms and hurricanes it now anticipates being seen in the Atlantic during the 2023 season.

Back in May, NOAA had called for between 12 and 17 named tropical storms to form, with from 5 to 9 of those becoming hurricanes, and between 1 and 4 of those reaching major category 3 or higher wind speeds.

It gave a 40% chance of a near normal season and a 30% chance of the Atlantic hurricane season being above or below normal activity levels.

Now, fast-forward to the August forecast update and NOAA is calling for 14-21 named tropical storms, of which 6-11 could become hurricanes, and between 2-5 could become major hurricanes.

So, it’s an uplift on every front and NOAA now gives a 70% forecast confidence for these figures.

While the outlook is now 60% in favour of an above normal hurricane season, with a 25% chance it is near normal and just 15% that it falls below normal activity levels.

“Forecasters believe that current ocean and atmospheric conditions, such as record-warm Atlantic sea surface temperatures, are likely to counterbalance the usually limiting atmospheric conditions associated with the ongoing El Nino event,” NOAA explained.

“The main climate factors expected to influence the 2023 Atlantic hurricane activity are the ongoing El Nino and the warm phase of the Atlantic Multi-Decadal Oscillation, including record-warm Atlantic sea surface temperatures,” said Matthew Rosencrans, lead hurricane season forecaster with NOAA’s Climate Prediction Center. “Considering those factors, the updated outlook calls for more activity, so we urge everyone to prepare now for the continuing season.”

NOAA added that, “A below-normal wind shear forecast, slightly below-normal Atlantic trade winds and a near- or above-normal West African Monsoon were also key factors in shaping this updated seasonal forecast.”

Forecaster TSR also recently increased its forecast, citing a chance of trade-winds being neutral, or even favourable to storm development.

Add in the record-warm ocean temperatures and all forecasters are now betting these factors will outweight the counter effects from El Nino and drive more hurricanes and more activity.

As we also reported recently, some other forecasters continue to believe the warmer than normal SSTs alone can drive a more active season.

Adding in this latest forecast update to our Artemis average, across the forecasters we track, keeps it at 16 named storms and 8 hurricanes, but now raises it by one to 4 major hurricanes, so an increasingly above the historical average season.

Track the 2023 Atlantic tropical storm and hurricane season on our dedicated page and we’ll update you as new information emerges.