Winds between 9,000 and 11,000 feet will give us some indication of how thunderstorms will move on any given day. These winds are also compared to higher level winds (500 mb) to determine how much wind shear is present. If the winds are stronger and from a different direction at higher levels, thunderstorms will tend to persist longer, move farther before dissipating, and cause thunderstorms to organize into clusters, lines, or in extreme cases, into rotating supercells. If the shear is too strong, thunderstorms may be torn apart before they develop. If the shear is too weak, the storms will tend to move slowly, but will also tend to dissipate soon after they develop.