2018 Hurricane Forecasts Not as Fearsome as 2017

Yet ‘Below-Normal’ Season Unlikely
May 30, 2018

Batten down your hatches, America.

Well, at least be ready to do so.

The National Oceanic and Atmospheric Administration’s Climate Prediction Center released its 2018 Atlantic hurricane season forecast on May 24 and although it isn’t as concerning as last year’s was, it is still not something you’d want to ignore.

The center is predicting a 75 percent chance of the 2018 season having above normal (35 percent) or near-normal (40 percent) activity, with only a 25 percent chance of a below-normal season. NOAA’s forecasters predicted a 70 percent likelihood of 10 to 16 named storms (winds of 39 mph or higher), of which five to nine could become hurricanes (winds of 74 mph or higher) including one to four major hurricanes (category 3, 4 or 5; winds 111 mph or higher).

Last year’s May forecast called for a 45 percent chance of an above-normal season and a 35 percent chance of a near-normal season with a mere 20 percent chance of a below-normal season. NOAA forecasters called for 11 to 17 named storms and five to nine hurricanes, with two to four becoming major. The season ended up tied as the fifth-most active season since records began in 1851. There were 17 named storms, 10 hurricanes and six major blows.

An average season produces 12 named storms and six hurricanes, three of the major variety.

The possibility of a weak El Niño developing, along with near-average sea surface temperatures across the tropical Atlantic Ocean and Caribbean Sea, are two of the factors driving NOAA’s forecast this year.

NOAA’s predictions follow the pattern set in April when the Colorado State University Tropical Meteorology Project released its first (it adjusts them frequently) 2018 Atlantic hurricane season forecast.

Colorado forecasters, led by Phil Klotzbach, called for a slightly above average season with 14 named storms and seven hurricanes, three reaching major strength. They, too, said a weak El Niño could develop, noting that odds of a strong El Niño appear relatively low.

Too bad – a strong El Niño would probably increase upper-level westerly winds across the Caribbean into the tropical Atlantic, tearing apart hurricanes before they form.

The forecasters also commented on slightly cooler than normal sea surface temperatures in the eastern tropical Atlantic. Colder-than-normal sea surface temps provide less fuel for tropical cyclone formation and intensification.

The Colorado team uses a “hindcasting” technique, comparing current conditions to over 60 years of historic data to make its hurricane predictions. So far, the 2018 season is exhibiting characteristics similar to 1960, 1967, 1996, 2006 and 2011.

“The years 1960, 1967 and 2006 had near-average Atlantic hurricane activity, while 1996 and 2011 were both above-normal hurricane seasons,” said Klotzbach.

The Colorado forecasters predicted 2018 Atlantic hurricane activity at about 135 percent of the average season. 2017’s actual activity was about 245 percent of the average season, notable for Harvey, which smashed into Texas and especially Houston; Irma, which gave Floridians fits; and Maria, which devastated Puerto Rico and the American Virgin Islands.

— Rick Mellerup

rickmellerup@thesandpaper.net

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