Nova Scotia·Weather

Atlantic hurricane season outlook updated, more storms expected

Likelihood of greater storm activity increased due to warm ocean temperatures in the North Atlantic.

CBC meteorologist Ryan Snoddon says warm ocean temperatures will likely play larger role

Satellite image of Hurricane Fiona as raced towards Atlantic Canada on September 23, 2022.
A satellite image of Hurricane Fiona as raced towards Atlantic Canada on Sept. 23, 2022. (NASA Earth Observatory)

The U.S. National Oceanic and Atmospheric Administration has updated its outlook for the rest of the Atlantic hurricane season.

Forecasters on Thursday increased the likelihood of an above-normal season to 60 per cent, which is up from a 30 per cent chance in the outlook the agency issued in May.

The earlier projection of 12 to 17 named storms has now increased to 14 to 21 storms.

Of those storms, six to 11 could become hurricanes. Of those, two to five may become major hurricanes of Category 3 strength or greater.

NOAA is now projecting a 60 per cent chance of a near average hurricane season.
NOAA is now projecting a 60 per cent chance of an above-normal hurricane season. (Ryan Snoddon/CBC)

It's important to remember that these outlooks are for overall season activity, not storms that make landfall.

Heading into the season, it was thought that a developing El Niño could limit tropical storms and hurricane activity. When a warmer-water El Niño event is underway in the Pacific, stronger wind shear occurs over the Caribbean and tropical Atlantic Ocean. This wind shear can suppress the development and growth of tropical storms and hurricanes.

While El Niño has developed, its impacts on the tropical region are now looking less likely to counterbalance the other major factor of this season — warm ocean temperatures.

While temperatures in the North Atlantic were expected to be above average, the record warmth in the basin has been making headlines over the past few months. 

Sea surface temperatures in the North Atlantic have been setting records for much of 2023.
Sea-surface temperatures in the North Atlantic have been setting records for much of 2023. (Climate Reanalyzer/University of Maine)
Sea-surface temperatures in the North Atlantic have been well above average since the early spring and have been on record-crushing pace since June.

Warmer than average temperatures in the main tropical development region are expected to be a key factor for the remainder of the season.
Warmer-than-average temperatures in the main tropical development region are expected to be a key factor for the remainder of the hurricane season. (Climate Reanalyzer/University of Maine)

While the largest sea-surface temperature anomalies are currently around Atlantic Canada and Greenland, the tropical Atlantic and main storm development region is also running well above average.

The warmer ocean temperatures in the tropics will be key, with the West African monsoon season expected to be near-to-above average.

Large areas of thunderstorms off the coast of Africa are the seeds for tropical systems, especially when they roll into ocean water that is running warmer than normal.

El Niño is looking less likely to counter the warm ocean temperatures in the Atlantic.
El Niño is looking less likely to counter the warm ocean temperatures in the Atlantic. (Ryan Snoddon/CBC)

While we can't ultimately tell where and when these storms will occur, we do know that the month of September is historically the most active.

Hurricane peaks in September in the Atlantic ocean.
Hurricane season peaks in September in the Atlantic Ocean. (NOAA)

With damage from post-tropical storms Fiona in 2022 and Dorian in 2019 fresh on the minds of Atlantic Canadians, we really don't need a reminder of how destructive these storms can be.

The updated outlook is a good reminder that the time to be ready and prepared is almost here.

ABOUT THE AUTHOR

Ryan Snoddon

Meteorologist

Ryan Snoddon is CBC's meteorologist in Nova Scotia and New Brunswick.

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