Hurricane researchers continue to predict near-average Atlantic season

hurricane

Colorado State University hurricane researchers continue to predict a near-average hurricane season for the Atlantic basin in 2016, citing several competing factors.

The tropical eastern and central Pacific currently has slightly cooler-than-normal sea surface temperatures, and there is a potential for a transition to weak La Niña over the next several months. Upper-level winds over the tropical Atlantic have been much weaker this year than the past few years, indicating a more conducive environment for hurricane formation. However, the far North Atlantic remains quite cold, and this tends to create atmospheric conditions associated with increased sinking and drying motion. The atmosphere over most of the tropical Atlantic has been quite dry so far this hurricane season.

The CSU Tropical Meteorology Project team is predicting a total of 11 additional named storms to form after Aug. 1.  Of those, researchers expect five to become hurricanes and two to reach major hurricane strength (Saffir/Simpson category 3-4-5) with sustained winds of 111 miles per hour or greater. These forecast numbers do not include Tropical Cyclones Alex, Bonnie, Colin and Danielle, which formed prior to Aug. 1. They do include Earl, which is currently active in the western Caribbean.

The team bases its forecasts on over 60 years of historical data that include 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 2016 hurricane season is exhibiting characteristics similar to 1958, 1959, 1966, 1978, 1992 and 1998.

“In general, most of these seasons experienced near to slightly above-average activity, with 1998 being a very active season,” said Phil Klotzbach, research scientist in CSU’s Department of Atmospheric Science and lead author of the report.

The team predicts that 2016 hurricane activity will be about 100 percent of the average season. By comparison, 2015’s hurricane activity was about 65 percent of the average season.

This is the 33rd year that the CSU hurricane research team has issued the Atlantic basin seasonal hurricane forecast. The late William Gray, professor in the Department of Atmospheric Science for over 40 years, launched the report in 1984.

The CSU forecast is intended to provide a best estimate of activity to be experienced during the upcoming season – not an exact measure.

Klotzbach cautioned coastal residents to take proper precautions.

“It takes only one landfall event near you to make this an active season,” Klotzbach said.

The report also includes the post-July 31 probability of major hurricanes making landfall on U.S. soil:

  • 51 percent for the entire U.S. coastline (full-season average for the last century is 52 percent)
  • 30 percent for the U.S. East Coast including the Florida peninsula (full-season average for the last century is 31 percent)
  • 29 percent for the Gulf Coast from the Florida panhandle westward to Brownsville (full-season average for the last century is 30 percent)
  • 41 percent for the Caribbean (full-season average for the last century is 42 percent)

The forecast team also tracks the likelihood of tropical storm-force, hurricane-force and major hurricane-force winds occurring at specific locations along the coastal United States, the Caribbean and Central America through its Landfall Probability website.

The site provides information for all coastal states as well as 11 regions and 205 individual counties along the U.S. coastline from Brownsville, Texas, to Eastport, Maine.

Landfall probabilities for regions and counties are adjusted based on the current climate and its projected effects on the upcoming hurricane season.

Klotzbach updates the site regularly with assistance from the GeoGraphics Laboratory at Bridgewater State University in Massachusetts.

Funding for this year’s report has been provided by Interstate Restoration, Ironshore Insurance, Macquarie Group and a grant from the G. Unger Vetlesen Foundation.

Atlantic Basin hurricane forecast for 2016 (Released Aug. 4, 2016):

Tropical Cyclone Parameters Extended Range
(1981-2010 Climatological Median Forecast for 2016 in parentheses)
Named Storms (12)* 15
Named Storm Days (60.1) 55
Hurricanes (6.5) 6
Hurricane Days (21.3) 23
Major Hurricanes (2.0) 2
Major Hurricane Days (3.9) 5
Accumulated Cyclone Energy (92) 100
Net Tropical Cyclone Activity (103%) 110
* Numbers in ( ) represent full-season medians based on 1981-2010 data.

CSU University Communications Staff