Forecasters Calling for a Near-Normal 2019 Hurricane Season

El Niño Would Temper Atlantic Storm Power
By RICK MELLERUP | May 08, 2019
Source: US National Weather Service Eastern Region HQ

Surf City —

The difference between El Niño and La Niña is far more consequential than the difference between saying potato or potahto.

The latter can merely provide a tip as to whether a speaker is an American or a Brit. The former plays a huge role in predicting how hurricane seasons in both the Atlantic and Pacific will develop.

“Simply put,” reads an explanation on the National Oceanic and Atmospheric Administration’s website, “El Niño (warmer-than-normal sea surface temperatures in the central and eastern Pacific Ocean) favors stronger hurricane activity in the central and eastern Pacific basins, and suppresses it in the Atlantic basin. Conversely, La Niña (cooler-than-normal sea surface temperatures in the central and eastern Pacific) suppresses hurricane activity in the central and eastern Pacific basins, and enhances it in the Atlantic basin.”

El Niño was very much on the minds of meteorologists and climatologists this spring as they prepared their 2019 Atlantic basin hurricane forecasts.

The private weather forecasting company AccuWeather led off the spring hurricane forecast season on April 3, predicting a near- to slightly above-normal season with 12 to 14 named storms including five to seven hurricanes, two to four of which will become major, Category 3 or above, blows. The major reason for the company’s forecast was an El Niño, which AccuWeather proposed “should continue right through the summer, including the most active time of the season: August, September and October.”

“If this current El Niño continues or strengthens, then the number of tropical storms and hurricanes will be near or below normal,” temporized AccuWeather Atlantic hurricane expert Dan Kottlowski. “If the El Niño weakens and goes neutral, the number of tropical storms and hurricanes could actually be higher than normal.”

The very next day the Colorado State University Tropical Meteorology Project team also largely pinned its 2019 Atlantic basic hurricane forecast on the presence of an El Niño.

“A weak El Niño has recently developed in the tropical Pacific,” read an April 4 CSU press release. “CSU anticipates that these weak El Niño conditions are likely to persist through the peak of the Atlantic hurricane season. El Niño tends to increase upper-level westerly winds across the Caribbean into the tropical Atlantic, tearing apart hurricanes as they try to form.”

Other factors such as the tropical Atlantic being slightly cooler than normal played into CSU’s 2019 Atlantic basin hurricane forecast – “Colder-than-normal sea surface temperatures in the tropical Atlantic provide less fuel for tropical cyclone formation and intensification” – but the Tropical Meteorology Team led off its forecast talking about El Niño.

The team predicted 13 named storms during the Atlantic hurricane season, which runs from June 1 to Nov. 30. Five are expected to become hurricanes, with two reaching major hurricane strength (Saffir/Simpson category 3-4-5) with sustained winds of 111 mph or greater. The average for the years 1981-2010 was 12.1 named storms and 6.4 hurricanes of which 2.7 broke the “major” barrier, allowing the CSU scientists to say the 2019 Atlantic basin hurricane season will have “slightly below-normal activity.”

The Weather Company, an IBM business, fell into line on May 6 when it released its 2019 Atlantic basin hurricane forecast.

“El Niño conditions are expected to persist or, at worst, slowly weaken over the next six months, which should act to help suppress activity a bit,” said Todd Crawford, Weather Company chief meteorologist.

Crawford and his crew predicted 14 named storms and seven hurricanes including three Category 3 or stronger, meaning it is calling for a slightly above-average season. But a company statement added that if El Niño persists it may lower its hurricane season outlook’s numbers a touch in its next update.

NOAA is scheduled to release its 2019 Atlantic basin hurricane forecast on May 23. It waits until just before the Atlantic hurricane season starts to issue its forecast because it says waiting has “proven to be advantageous when it comes to hitting the mark.”

“NOAA’s outlooks are issued with a 70% confidence level that hurricane activity will fall within our predicted ranges, and they are accurate 70% of the time,” the government administration says explaining its later-than-the-rest rollout.

Even if the 2019 hurricane season is slightly above-normal it would be a welcome relief. The last season to come in below-normal was 2015 with 11 named storms, four hurricanes and two major hurricanes. There were 15 named storms, seven hurricanes and four major hurricanes in 2016, 17 named storms and 10 hurricanes, six of which were of the major variety, in 2017 and 15 named storms and eight hurricanes including two majors in 2018.

— Rick Mellerup


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