Hurricane researchers on Thursday predicted a slightly above-average Atlantic hurricane season this year, citing the relatively low likelihood of a significant El Niño as a primary factor.
In its pre-hurricane season report issued Thursday the team from Colorado State University predicted 14 named storms during the Atlantic hurricane season, which runs from June 1 to Nov. 30. Of those, researchers expect seven to become hurricanes and three to reach major hurricane strength on the Saffir/Simpson scale, with sustained winds of 111 miles per hour or greater.
Of course, as the islands well know, it only takes one storm hitting where you are to ruin the whole season.
The CSU Tropical Meteorology Project team predicted that 2018 hurricane activity will be about 135 percent of the average season. By comparison, 2017’s hurricane activity was about 245 percent of the average season. The 2017 season was most notable for Hurricanes Harvey, Irma and Maria, which devastated the United States and portions of the Caribbean.
The forecast is based on more than 60 years of historical data, including Atlantic sea surface temperatures, sea level pressures, vertical wind shear levels (the change in wind direction and speed with height in the atmosphere,) El Niño (warming of waters in the central and eastern tropical Pacific), and other factors.
So far, the 2018 hurricane season is exhibiting characteristics similar to 1960, 1967, 1996, 2006 and 2011, according to Thursday’s report.
“The years 1960, 1967 and 2006 had near-average Atlantic hurricane activity, while 1996 and 2011 were both above-normal hurricane seasons,” said Phil Klotzbach, research scientist in the Department of Atmospheric Science and lead author of the report.
Tropical Atlantic sea surface temperatures are currently near their long-term average values. Consequently, they are considered a neutral factor for 2018 Atlantic hurricane activity at the present time, the meteorologists said.
A weak La Niña this past winter has weakened slightly over the past few weeks. While there is the potential that a weak El Niño could develop by the peak of the Atlantic hurricane season, the odds of significant El Niño development appear relatively low. El Niño tends to increase upper-level westerly winds across the Caribbean into the tropical Atlantic, tearing apart hurricanes as they try to form.
The western tropical North Atlantic is currently slightly warmer than normal, while the eastern tropical Atlantic is slightly cooler than normal. Colder-than-normal sea surface temperatures provide less fuel for tropical cyclone formation and intensification. They are also associated with a more stable atmosphere as well as drier air, both of which suppress organized thunderstorm activity necessary for hurricane development.
This is the 35th year that the CSU hurricane research team has issued the Atlantic basin seasonal hurricane forecast. William Gray launched the report in 1984 and continued to be an author on them until his death in 2016.
CSU said its forecast is intended to provide the best estimate of activity to be experienced during the upcoming season – not an exact measure.
Bell cautioned coastal residents to take proper precautions.
The report also included the probability of major hurricanes making landfall:
63 percent for the entire U.S. coastline (average for the last century is 52 percent)
39 percent for the U.S. East Coast, including the Florida peninsula (average for the last century is 31 percent)
38 percent for the Gulf Coast from the Florida panhandle westward to Brownsville (average for the last century is 30 percent)
52 percent for the Caribbean (average for the last century is 42 percent)
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