Tropical Storm Bret forms in the Atlantic Ocean

But this year there is also El Niño, which arrived earlier this month. The intermittent climate phenomenon that can have far-reaching effects on weather around the world, including a reduction in the number of Atlantic hurricanes.

“It’s a pretty rare condition to have both going on at the same time,” Matthew Rosencrans, the lead hurricane forecaster at NOAA’s Climate Prediction Center, said in May.

In the Atlantic Ocean, El Niño increases the amount of wind shear, or the change in wind speed and direction from the ocean or land surface to the atmosphere. Hurricanes need a calm environment to form, and the instability caused by increased wind shear makes those conditions less likely. (El Niño has the opposite effect in the Pacific, reducing the amount of wind shear.) Even in average or below-average years, there’s a chance that a powerful storm will make landfall.

As global warming worsens, that probability increases. There is a solid consensus among scientists that hurricanes are becoming more powerful due to climate change. While there may be no more named storms in general, the likelihood of major hurricanes is increasing.

Climate change also affects the amount of rain storms can produce. In a warming world, the air can hold more moisture, meaning a named storm can hold and produce more rain, as Hurricane Harvey did in Texas in 2017, when some areas received more than 40 inches of rain in less than 48 hours.

Researchers have also found that storms have slowed down and spent longer over areas in recent decades.

When a storm slows down over water, the amount of moisture the storm can absorb increases. When the storm slows overland, the amount of rain that falls in a single location increases; for example, in 2019, Hurricane Dorian slowed to a creep over the northwestern Bahamas, resulting in a total rainfall of 22.84 inches in Hope Town during the storm.