Below-average Atlantic hurricane activity predicted for rest of 2014
This Thursday, July 3, 2014, satellite image taken at shows Hurricane Arthur near the coasts of South Carolina and North Carolina. (AP Photo/NOAA)
Emily Chan, CTVNews.ca
Published Saturday, August 2, 2014 1:33PM EDT
This year’s hurricane season could be milder than average according to a new study from Colorado State University.
The report forecasts that the Atlantic coast will experience about three more hurricanes, nine more named storms and one more major hurricane before the year’s end. In past years, there have been an average of 5.5 hurricanes, 10.5 named storms, and two major hurricanes still expected at this time of year.
Storms are classified as hurricanes when they have sustained winds of 119 km/h. Major hurricanes are defined as a Category Three, Four, or Five storm. This range includes any hurricane with winds of 178 km/h or more.
This year’s reduced activity is caused by a combination of unusual factors.
Ocean surface temperatures are cooler than normal in the tropical and subtropical eastern Atlantic. In addition to this, the report states that sea level pressures are abnormally high, and there is a strong vertical wind shear. Wind shear describes changes in wind speed and direction, and can be a major factor in hurricane formation.
Hurricane Katrina was at one point a Category Five hurricane, but had dropped down to a Category Three storm by the time it made landfall in Louisiana and Mississippi. According to a report by the National Hurricane Centre in the U.S., Katrina had top winds of 204 km/h when it touched down.
Out of all the cyclone basins in the world, the Atlantic basin, which stretches from the Carribean to the Maritimes, has the most variation between hurricane seasons. Because of this, the authors wrote, people are especially curious about what type of activity to expect in the future.
“There is a general interest in knowing what the odds are for an active or inactive season,” Philip J. Klotzbach and William M. Gray wrote.
Klotzbach and Gray used past hurricane statistics and patterns to predict future ones, and to compare this coming season to the average seasons between 1981 and 2010.
The report, titled Forecast of Atlantic Seasonal Hurricane Activity and Landfall Strike Probability for 2014, was published online on the Colorado State University Tropical Meteorology Project website and released on July 31.