The coming Atlantic hurricane season will likely still be unusually active, although not as severe as initially predicted, according to a forecast update from the National Oceanic and Atmospheric Administration (NOAA) on Thursday.
Why it matters: If the forecast proves correct, it would be the seventh straight year of above-average activity in the tropical Atlantic.
- The past two hurricane seasons have both exhausted the list of 21 storm names, which was unprecedented. The 2020 season was the most active season ever.
- However, the current hurricane season is unlikely to match the extreme activity of the past two seasons, NOAA scientists said at a news conference.
The big picture: NOAA predicts a 60% chance that the coming hurricane season will be above average, with a 30% chance of near-normal activity and only a 10% chance of below-normal numbers of tropical cyclones.
- In terms of the number of storms, the agency predicts a 70% chance of 14 to 20 named storms. Of these, six to 10 would become hurricanes, and of these, three to five would intensify into major Category 3 or higher hurricanes.
- These numbers are slightly down from NOAA’s first hurricane season forecast released in May. There have already been three named storms in the Atlantic this season.
- August and September are typically the most active months in the Atlantic hurricane season.
- A typical Atlantic hurricane season has 14 named storms, seven hurricanes and three major hurricanes, according to the National Hurricane Center.
What they say: “It only takes one storm to devastate a community,” said Matthew Rosencrans, NOAA’s chief hurricane forecaster.
context: NOAA bases its forecast on several factors, including fluctuations in sea surface temperature in the North Atlantic basin and the continued presence of a La Niña event in the tropical Pacific.
- La Niña is characterized by cooler than average water near the equator. It can reduce winds in the middle and upper atmospheres all the way to the Atlantic Ocean.
- These weaker winds can boost hurricane development by reducing wind shear, which can tear emerging storms apart.
- Climate studies show that increasing ocean and air temperatures are leading to wetter, stronger hurricanes, and that rapidly intensifying storms, like Hurricane Ida last year, are more likely today than they were just a few decades ago.
- Forecasters also accounted for greater-than-expected variability in sea surface temperature in the tropical Atlantic, compared to the signal indicating consistently mild waters observed just a few months ago, Rosencrans said.
Of interest: The country’s weather and climate agency currently has an acting director of the National Hurricane Center, Jamie Rhome. The previous director was appointed as the new head of the National Weather Service.
Threat level: The greatest threat to life from tropical storms and hurricanes is inland flooding, as evidenced by Hurricane Ida, which killed more people in the northern Mid-Atlantic from flash flooding than where it made landfall along the Gulf Coast.