Above normal 2018 Atlantic hurricane season ahead: Experts
Thursday, April 5, 2018, 17:06 - The tropical meteorology research group at Colorado State University (CSU) Department of Atmospheric Sciences is anticipating a slightly above average Atlantic hurricane season for 2018.
With less than two months to go in the Atlantic hurricane pre-season, forecasts anticipate it is not likely we will see a repeat of 2017 which was one of the most active and destructive this century.
Last year's 17 named storms made it the fifth most active season since records began in 1851. We saw the highest total accumulated cyclone energy and the highest number of major hurricanes since 2005, with all 10 of the seasons hurricanes occurring in one after the other.
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Key ingredients for an almost neutral season
The key ingredients that can make this 2018 season just a bit more active than usual include:
- A transition between a current weakening La Niña and a more than likely weak El Niño by the peak of the hurricane season. With a weak or non-existent El Niño, we should see near neutral wind shear conditions overall. El Niño tends to increase upper-level westerly winds across the Caribbean into the tropical Atlantic, tearing apart developing tropical storms that can eventually evolve into hurricanes. It is hard to say at this point how strong the El Niño anomaly will be in the middle of the season, but at this point most model predictions are anticipating it will not be much greater than 0.5oC. Diagram La Niño/El Niño forecast for coming months
- The tropical Atlantic surface water temperature values are close to their long time average, so unless there is a drastic change in the coming months, they will not be a major influential factor for storm development. The eastern tropical Atlantic, where a good number of storms develop, is actually cooler than average. If it remains in this less energetic mode throughout the season, developing storms will have less fuel for development and intensification. The atmosphere will also be in a more stable than usual mode with a higher probability of dry air entrainment in the region, ingredients that tend to suppress organized thunderstorm activity needed for hurricane development.
La Niño/El Niño forecast for coming months
14 named storms and 7 hurricanes
For this 2018 season which begins on June 1st and ends November 30th, the CSU Atmospheric Sciences Department report lead by Dr. Philip Klotzbach is anticipating 14 named storms, 2 more than the 1981-2010 average. Seven of those storms are expected to become hurricanes, a number close to the 6.5 average value, and 3 could end up gaining a Category 3 or higher status, making them major hurricanes.
Dr. Klotzbach also points out that this 2018 Atlantic hurricane pre-season is looking a lot like those of 1960, 1967, 1996, 2006 and 2011, with 1996 and 2011 being above average seasons and the rest near average. In terms of the overall activity, the 2018 season could be 135 percent more active than average, almost half of what was reported for the 2017 season which was an overwhelming 245 percent more active than average.
Historical Landfalls of Hurricanes for US until 2011 NOAA
This season will also see an above average probability of hurricanes making landfall along the US coastline, 63 percent, as compared to the 52 percent average for the past century. Specific landfall forecasts include a 39 percent landfall probability for the U.S. east coast including the entire Florida peninsula (average for the last century is 31 percent), 38 percent for the Gulf Coast from the Florida Panhandle westward to Brownsville, Texas (average for the last century is 30 percent) and 52 percent for the Caribbean (average for the past century is 42 percent).
The CSU team will update this forecast on May 31st, July 2nd and August 2nd as ocean-atmosphere-land-cryosphere parameters are also updated.