110 Revisiting the Influence of Topography on Local Convective Environments Using High-Resolution Model Output

Tuesday, 23 October 2018
Stowe & Atrium rooms (Stoweflake Mountain Resort )
Branden Katona, Pennsylvania State Univ., Univ. Park, PA; and P. Markowski

Past work by Katona et al. (2016) demonstrated that topography is associated with perturbations to instability, low-level wind shear, and the significant tornado parameter (STP). Modifications were evident in river valleys, along coastlines, and along ridge tops. Low-level flow direction also affects how these convective parameters are perturbed by the terrain, with the sign of the local perturbation to low-level wind shear changing in association with a change in low-level flow.

This new work seeks to further refine the ways in which terrain can modify convective environments. Now that additional convective days have been added to the data set, these days are partitioned into wider variety of low-level flow regimes to better capture the effects of terrain in both localized cross- and along-topography flows. Additionally, convective days are classified according to static stability, and high-shear, low-CAPE environments are analyzed in comparison to environments more commonly seen in the Great Plains (those having moderate-to-high CAPE values) to determine the role of terrain in both scenarios. Lastly, several localized terrain features in the eastern United States will be analyzed in more depth to determine under which conditions these features are most likely to exert a significant influence on the local convective environment.

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