POSTED: Tuesday, June 22, 2010 - 5:17pm
UPDATED: Tuesday, June 22, 2010 - 5:17pm
Information obtained through May 2010 indicates that the 2010 Atlantic hurricane season will be much more active than the average 1950-2000 season. We estimate that 2010 will have about 10 hurricanes (average is 5.9), 18 named storms (average is 9.6), 90 named storm days (average is 49.1), 40 hurricane days (average is 24.5), 5 major (Category 3-4-5) hurricanes (average is 2.3) and 13 major hurricane days (average is 5.0). The probability of U.S. major hurricane landfall and Caribbean major hurricane activity is estimated to be well above its long-period average. We expect Atlantic basin Net Tropical Cyclone (NTC) activity in 2010 to be approximately 195 percent of the long-term average. We have increased our seasonal forecast from early April.
We expect that the current trend from El Niño to neutral conditions will persist and that weak La Niña conditions will develop by the most active portion of this year’s hurricane season (August-October). The expected trend towards weak La Niña conditions should lead to reduced levels of vertical wind shear compared with what was witnessed in 2009. Another reason for our forecast increase is due to the persistence of anomalously warm sea surface temperatures in both the tropical and North Atlantic. Current SST anomalies are running at near-record warm levels. These very warm waters are associated with dynamic and thermodynamic factors that are very conducive for an active Atlantic hurricane season. Another factor in our forecast increase is the weaker-than-normal Azores High that prevailed during April-May. Weaker high pressure typically results in weaker trade winds that are commonly associated with more active hurricane seasons. Another important factor is that we are in the midst of a multi-decadal era of more major hurricane activity. Major hurricanes cause 80-85 percent of normalized hurricane damage.