The 15th named storm of the season was upgraded to "Sub-Tropical Storm Otto" this afternoon after Hurricane Hunters found nearly hurricane force winds at flight level late Wednesday afternoon. Otto will be no threat to any land areas as it is expected to move to the northeast through the next several days.
Otto is considered a sub-tropical storm as it's energy is getting derived from a combination of warm surface water and the upper level dynamics of low pressure aloft. Normally, purely tropical systems derive all there energy from warm surface water temperatures and the latent heat of evaporation that fuels convection (thunderstorms) in the storm system.
