It is now well known that mesoscale convective systems tend to strongly excite gravity waves with vertical structures corresponding to the first few vertical "modes" of the troposphere (horizontal phase speeds in the range 20-50 m/s). In addition to these strongly forced modes, however, there are also more weakly forced modes with vertical wavelengths much smaller than the depth of the troposphere (horizontal phase speeds in the range 6-10 m/s). This talk will present evidence from both observations and numerical models to show that these "ultra-short" vertical modes, although weakly excited, are often more effective in triggering subsequent convection than their deeper and more strongly forced counterparts.

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*email: stefan.tulich@noaa.gov
*Preference: Invited