Warm enough ocean temperatures & large enough Coriolis force (Latitudes greater than 10 degrees)
Eye Eye Wall Rain Bands
The pressure in the eye near the surface is very low and controls the hurricanes strength. The pressure high above the surface in the eye is High cause air to sink and clouds to dissappear.
Surface pressure is lowest in the eye of a hurricane. Wind speed is maximum in the eye wall and is usually calm in the eye. Intense rain, winds, and possibly tornadoes are most likely in the eye wall.
Katrina August 28, 2005 TRMM (Tropical Rainfall Measuring Mission)
El Nino and Hurricanes
Red-total hurricanes and tropical storms (named storms) Yellow : total hurricanes Green : cat 3 or above Are hurricanes getting more frequent or more intense?
Total power dissipated by hurricanes PDI seems to be increasing since From: And