Climatological and environmental conditions associated with funnel cloud occurrences without tornadoes have been examined and compared with corresponding conditions of the tornado environment. The purpose was to determine if there were significant environmental differences between these two weather phenomena. Seasonal and diurnal distributions, air mass instability, tropospheric vertical wind shear, and geographical distributions are compared.
The overall results show that the funnel cloud environmental characteristics are statistically very closely related to those of the tornado. As with the tornado environment, a large lower tropospheric vertical wind shear is observed. This is thought to be an important dynamical feature of both the tornado and the funnel cloud.