Indicators suggest reduced hurricane activity for the peak of the 2012 Atlantic Hurricane Season. However, storms are more likely to develop in the West Atlantic and Gulf of Mexico with a higher threat to land. Since 1950, 100 percent of years saw the occurrence of a September tropical storm, a hurricane in 98 percent of years and a major hurricane in 74 percent of years. A major landfalling U.S. hurricane cannot be ruled out, despite the quiet period of recent weeks.
East and Central Atlantic
Cool water temperatures, wind shear and stable air will diminish tropical cyclone activity.
- Warm water with temperatures exceeding 27 degrees C is essential for tropical cyclone formation. We only marginally see this in the East Atlantic, and this is not expected to change for the balance of the 2012 Atlantic hurricane season. Water temperatures are marginally sufficient for tropical cyclone development in the East and Central Atlantic.
- The difference between upper and lower-level wind speeds (known as wind shear) has been too strong to enable tropical cyclone development, particularly in the Central Atlantic. East Atlantic shear has been intermittent, particularly in recent weeks.
- Air has been too stable to allow deep thunderstorm development and organization, which are the initial phases of tropical cyclone development. While the Central Atlantic has remained stable, the East Atlantic has been growing more unstable in recent weeks.