2006 Atlantic Ocean Tropical Cyclones

Tropical Cyclone Cyclogenesis Date Cyclolysis Date Highest Saffir-Simpson Category Maximum 6-hr Sustained Wind (kt) Maximum 6-hr Wind Gust (kt) Accumulated Cyclone Energy (ACE*) Index (kt2) Landfall Information (date, location and sustained winds)
Zeta 12/30/05 1/5/06 TS 55 65 1.1075 x 104 (2005 value)
3.3500 x 104 (2006 value)
Alberto 6/11/06 6/14/06 TS 60 75 2.6400 x 104 6/13/06 Apalachicola Bay (TS - 40kt)
Beryl 7/19/06 7/21/06 TS 50 N/A 2.173 x 104
Chris 8/01/06 8/04/06 TS 55 N/A 2.358 x 104
Debby 8/23/06 8/26/06 TS 45 N/A 2.1425 x 104
Ernesto 8/25/06 8/30/06 Cat 1 65 N/A 3.5900 x 104 8/29/06 Plantation Key (TS - 39kt)
8/31/06 - Long Beach, NC (TS - 61kt)
Florence 9/05/06 9/15/06 Cat 1 80 N/A 12.2207 x 104
Gordon 9/11/06 9/21/06 Cat 3 105 N/A 21.4150 x 104
Helene 9/14/06 9/27/06 cat 3 105 N/A 27.8713 x 104
Isaac 9/28/06 10/03/06 Cat 1 75 N/A 6.7250 x 104

*The Accumulated Cyclone Energy (ACE) Index is calculated by summing the squares of the estimated 6-hourly maximum sustained wind speed in knots (Vmax2) for all periods in which the tropical cyclone is a tropical storm or greater intensity (sustained winds of 34 kt or greater). Note that the official NOAA definition of the ACE Index does not include those periods when the system is characterized as sub-tropical. However, we are including this information to allow for comparison between individual cyclones across all basins, many of which contain records which inadequately distinguish between tropical and subtropical cyclones. For a complete description of the ACE Index see Bell and Chelliah (2006), Journal of Climate (19) 590-612.


The Saffir-Simpson Scale for Tropical Cyclones

Category Miles Per Hour (mph) Knots (kt) Kilometers Per Hour (km hr-1)
Tropical Storm (TS)
 39-73 34-63 63-118
Cat 1
 74-95 64-82 119-153
Cat 2
 96-110 83-95 154-177
Cat 3
 111-130 96-113 178-209
Cat 4
 131-155 114-135 210-249
Cat 5
 156 or greater 136 or greater 250 or greater