A preliminary investigation of the effects of orography on the environments of convective storms in the eastern United States

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Wednesday, 5 November 2014
Capitol Ballroom AB (Madison Concourse Hotel)
Branden Thomas Katona, Univ. of Oklahoma, Norman, OK; and P. Markowski

NCEP High-Resolution Rapid Refresh (HRRR) analyses of CAPE, CIN, vertical wind shear, SRH, and other convective storm forecasting parameters (e.g., composite indices such as the STP) are being used to develop a climatology of perturbations of these parameters in the eastern U.S. The goal is to identify how the terrain perturbs the environment on days on which convective storms are possible. We expect that the magnitude and perhaps even sign of terrain-induced perturbations in the convection environment will depend on the low-level wind direction, and it will likely be beneficial to partition cases by the low-level wind direction. Low-level wind directions are typically between southeasterly and westerly (rotating clockwise) on days on which convection occurs in the eastern U.S. Is there any pattern of systematic enhancement or reduction of CAPE, CIN, shear, etc. in the climatology, and how is the pattern be related to the terrain configuration? How do the amplitudes of the perturbations depend on the wind speed, and how does the pattern of the perturbations change as the wind direction changes? These represent just a few of the questions the climatology will eventually be able to address.