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Wind Shear
organized and unorganized convection

For convenience, we refer to storms in unsheared and sheared environments as unorganized and organized convection, respectively. Organized storms are longer-lived, usually have preferred areas of new updraft development, and often allow for some predictability of periodic severe weather events. Unorganized storms appear to be more chaotic, because of their nature and, to some extent, because of our lack of knowledge about them.

[Image: wind profiles for sheared and unsheared environments (34K)]

The examples of vertical wind profiles are similar to those that have been observed with different storm types: from the chaotic, light winds of unorganized summer storms, to the veering and increasing winds typical of organized storms. Although wind profiles of multicells and supercells appear to be similar, note both the stronger 5 to 10 thousand foot level winds and the greater low-level directional turning with supercells. These are causative factors of supercell updraft rotation. We must caution that vertical wind profiles are subject to rapid space and time changes, and better observation systems such as profilers will be important in improving practical storm-type forecasting. Also, these specific wind profiles are not the only arrangements that can occur with the different storm types. For instance, supercell surface winds may be easterly, with 5,000 foot winds southerly, and so on.

Terms for using data resources. CD-ROM available.
Credits and Acknowledgments for WW2010.
Department of Atmospheric Sciences (DAS) at
the University of Illinois at Urbana-Champaign.