In Reply to: How do phenomena such as El Nino and the North Atlantic Oscillation affect swings in the total number of hurricanes? posted by Lisa H. on 02/20/2006 at 15:47:
El Nino is associated with a warmer atmosphere (relative to the ocean) over the Atlantic, and more wind shear, both of which act to reduce the number of storms in the Atlantic. Conversely, there tend to be more storms over the central tropical Pacific during El Nino. Not sure about whether there is a detectable influence from the NAO.