The latest NOAA update, issued Thursday, calls for up to 19 named storms in the Atlantic. More than half could reach hurricane strength, and of those, as many as six could be major hurricanes (category 3 or stronger).
The NOAA initially predicted up to 18 named storms for the Atlantic.
The NOAA also says it is more confident this will be an above-average hurricane season.
Favourable conditions for the development of hurricanes are now in place over the tropical Atlantic Ocean and Caribbean Sea, where most storms are born. Sea-surface temperatures in that area are the third-warmest they've ever been. The warm temperatures are expected to persist throughout the remainder of hurricane season.
There's also a possibility that La Niña could redevelop in the Pacific Ocean.
According to Amanda De Monte, a meteorologist at The Weather Network, there are four key ingredients required to produce a tropical storm.
“You need warm waters of usually 26.5 degrees for a depth of around 50 meters. The presence of mid-level moisture needs to exist and a low pressure system needs to also be present. Along with this, you need the atmosphere to have low shear values, with winds coming from the same direction at various heights,” she explains.
The Atlantic basin has so far produced five tropical storms: Arlene, Bret, Cindy, Don and Emily. None has reached hurricane strength.