Watches Issued In Caribbean For Future Ernesto
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The 2023 Atlantic hurricane season has more uncertainty than usual due to a couple of key factors,according to a just-released outlook.
The Weather Now 24,an IBM Business,and Atmospheric G2 are forecasting 15 named storms,seven of which will become hurricanes and three of which will reach Category 3 status or stronger,in their initial outlook for 2023 released Thursday.
That matches the 30-year average tally for hurricanes and is close to the average number of named storms in a hurricane season.
Colorado State University also issued its April outlook Thursday morning. They forecast 13 named storms,six hurricanes and two major hurricanes. These are slightly reduced numbers compared to both the 30-year average and the forecast from The Weather Now 24.
A "near-average"hurricane season might not grab your attention,but there are two competing factors that may battle for control this year,as Todd Crawford,Ed Vallee and James Caron of AG2 put it.
If one of those factors dominates,the hurricane season could look quite different than average.
A Developing El Niño
The first signal we're watching isn't in the Atlantic Ocean,but rather the waters near the equator in the Pacific Ocean.
During the past three hurricane seasons,these Pacific equatorial waters were cooler than average – a condition known as La Niña. But that long-lasting La Niña finally disappeared,and this patch of water is now warming toward its counterpart,El Niño.
As of mid-April,a large majority of forecast models suggested an El Niño is likely to develop,possibly as soon as this summer. NOAA's Climate Prediction Center assigned a 61% chance that an El Niño will be in place by August through October,the heart of the Atlantic hurricane season.
The reason this strip of water far from the Atlantic Basin matters is that it's one of the strongest influences on hurricane season activity.
In El Niño hurricane seasons,stronger shearing winds often occur over at least the Caribbean Sea and some adjacent parts of the Atlantic Basin. This tends to limit the number and intensity of storms and hurricanes,especially if the El Niño is stronger,as we investigated in a March article.
The AG2 forecast team also noted a tendency in El Niño hurricane seasons for fewer Gulf of Mexico storms and more storms to either curl north,then northeast out into the open Atlantic Ocean or to impact parts of the East Coast.
That's because the Bermuda high tends to be weaker,and it's also due to a more persistent dip in the upper-level winds in the southeastern U.S. during El Niños,according to AG2.
The Atlantic Ocean Is Very Warm
Another factor in this outlook might have the opposite effect of El Niño in 2023.
Hurricane season generally begins when water temperatures reach the rough threshold of 80 degrees,which usually occurs between June 1 and Nov. 30. If other factors are equal,the deeper and warmer ocean water is,the stronger a hurricane can become.
But,according to the AG2 forecast team,Atlantic Basin water temperatures in early spring correlate well to a hurricane season's activity.
And much of the Atlantic Basin is warmer than usual for spring,particularly in the Gulf of Mexico,off the Southeast U.S. coast and in the eastern Atlantic.
What grabbed the AG2 team's attention was how close the overall warmth is right now compared to spring anomalies prior to the prolific 2020 hurricane season.
"(It) certainly gives one pause when relying on the potential El Niño event to keep the season quiet,"wrote Crawford and the AG2 team.
Klotzbach notes that the forecast from Colorado State University would have been lower if water temperatures were closer to average due to El Niño.
Prepare The Same Every Hurricane Season
What these outlooks cannot tell you is whether or not your area will get struck this season and when that might happen.
A season with fewer storms or hurricanes can still deliver the one storm that makes a season destructive or devastating.
In 2015,one of the strongest El Niños on record reduced the hurricane tally to four that season. However,one of those was Joaquin,which devastated the central Bahamas.
And it doesn't take a hurricane to be impactful,especially regarding rainfall flooding.
Also in the 2015 season,Tropical Storm Erika was ripped apart by wind shear and dry air near the Dominican Republic. But before that happened,it triggered deadly and destructive flooding in Dominica.
These outlooks serve as a reminder that the time to be ready for hurricanes is now. Information about hurricane preparedness can be found here.
MORE ON WEATHER.COM:
Changes You'll See In Hurricane Forecasts This Season
When The Last 'Quiet'Hurricane Season Happened
'Ian','Fiona'Retired As Hurricane Names
2022 Hurricane Season Recap:Florida's Luck Ran Out
The Weather Now 24’s primary journalistic mission is to report on breaking weather news,the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company,IBM.
