Above-normal number of Atlantic hurricanes forecast for 2021 season

The Canadian Hurricane Centre is forecasting an active hurricane season for 2021 on the heels of the most active hurricane season on record last year.

The centre released its forecast at a virtual briefing from its Dartmouth, N.S., office. 

The U.S. National Oceanic and Atmospheric Administration (NOAA) is predicting six to 10 hurricanes in 2021, compared to the average of seven.

Three to five of these hurricanes are expected to be major compared to the average of three, said Bob Robichaud, warning preparedness meteorologist with the centre. A major hurricane is classified as a hurricane with with sustained winds of at least 178 km/h.

Robichaud said NOAA is predicting between 13 and 20 named storms in 2021.

He said typically about 34 per cent of named storms, or four on average, find their way into Canadian waters.

"With more storms predicted, there's a pretty strong likelihood that we might see a few more storms than usual up here in Atlantic Canada as well," he said. 

The World Meteorological Organization has already issued the list of hurricane names for 2021 from a list that is rotated every six years. The first named storm of 2021 will be Ana. 

Robichaud said a new supplemental list of names has been put in place for the first time in the event they run out of names from the first list. 

On previous rare occasions when the main list of names was used up, the Greek alphabet was used. 

When a storm causes severe damage or loss of life, the World Meteorological Organization retires the name and replaces it on the six-year rotating list with another name. The name Dorian was retired after the storm wreaked havoc from the Bahamas to Nova Scotia in 2019.  

Although the hurricane season officially begins on June 1 and continues through Nov. 30, tropical storms in May like the one forming in the Atlantic this week off Bermuda are not unusual.

Robichaud said there is a 70 per cent chance of the storm currently forming in the Atlantic becoming the first named storm of the season in the next two days and a 90 per cent chance in the next five days. 

"There's a good chance here that we're going to see the seventh year in a row where we've seen a storm develop prior to the official start of the hurricane season," he said. 

There have been 19 named storms in May since 1950, according to Philip Klotzbach, who leads Atlantic hurricane season forecasting at Colorado State University.