The early long-range forecasts of the 2013 Atlantic hurricane season show Atlantic basin tropical cyclone activity slightly above average based on current and projected climate signals.
The Tropical Storm Risk extended forecast, issued Dec. 5 by Professor Mark Saunders and Dr. Adam Lea of the department of space and climate physics at the University College London, is published five months before the National Oceanic and Atmospheric Association (NOAA) and Colorado State University pre-season outlooks are released in the spring.
Josh Weiss, meteorologist of the Wilmington Forecast Office National Weather Service, said one of the key predictors of the hurricane season is the El Niño circulation with unusually warm temperatures.
“The face of the El Niño, which is the departure from normal of sea surface temperatures in the Pacific Ocean, plays a key role in how strong the Atlantic hurricane season will be,” Weiss said. “There’s other circulations as well but the El Niño is the most common one that people are aware of. … Generally when we have an El Niño in the Pacific Ocean, we have weaker or fewer hurricanes in the Atlantic. But if we don’t have an El Niño that’s when we tend to have more hurricanes in the Atlantic, so it’s hard to say this far out which way this will trend.”
The NOAA and Colorado State University predictions come out shortly before the Atlantic hurricane season begins on July 1. Weiss said the long-range patterns and teleconnections, like global atmospheric patterns, take a few months to develop.
“They wait to see how those teleconnections are going to look in the spring to forecast what they will be in the summer, which have an impact on what type of hurricane season we can expect,” Weiss said.
On Nov. 29, NOAA issued a press release for the end of the 2012 hurricane season stating it was a busy and destructive season with 19 tropical storms.
El Niño was predicted in the NOAA pre-season outlook, which led to underestimated numbers of named storms and hurricanes.
Several of the storms were short in duration, weak in intensity and stayed out in the Atlantic Ocean.
“This year proved that it’s wrong to think that only major hurricanes can ruin lives and impact local economies,” stated Laura Furgione, acting director of NOAA’s National Weather Service. “We are hopeful that after the 2012 hurricane season, more families and businesses all along the Atlantic and Gulf coasts become more ‘weather ready’ by understanding the risks associated with living near the coastline.”
Though the season was classified as above normal for activity, there have been 10 busier seasons in the past 30 years. The season began early in May with tropical storms Alberto and Beryl.
Since 1995, more than 70 percent of Atlantic hurricane seasons have been classified as above normal because of a well-established climate pattern, according to the NOAA.
Tropical Storm Risk will release a forecast update on April 5, 2013, before NOAA releases its predictions in late May. Hurricane season officially begins June 1.
“The past few seasons have been active so maybe that pattern will continue, but at this point there’s no way I can say that for sure,” Weiss said. “It only takes that one storm, so even if the prediction is for five hurricanes and we get that one into Wilmington, that could be a devastating season. Whereas we could have, like we did last year, where we have 19 storms but none of them directly impacted us so we kind of dodged a bullet again.”
He said the key is to always take preparedness actions and be ready if a hurricane does come.