A review of static stability indices and related thermodynamic parameters

Two types of parameters are computed and mapped for use in assessing their individual merits as predictors of occurrence and severity of thunderstorms. The first group is comprised of equivalent potential temperature, potential temperature, water vapor mixing ratio, and wind speed. Equivalent potential temperature maxima and strong gradients of equivalent potential temperature at the surface correlate well with regions of thunderstorm activity. The second type, comprised of the energy index, shear index, and energy shear index, incorporates some model dynamics of thunderstorms, including nonthermodynamic forcing. The energy shear index is found to improve prediction of tornadic and high-wind situations slightly better than other indices. It is concluded that further development and refinement of nonthermodynamic aspects of predictive indices are definitely warranted.

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Wind shear and wet and dry thermodynamic indices as predictors of thunderstorm motion and severity and application to the AVE 4 experimental data

The advantages and potential for the use of hourly surface static energy (cpT+gz+Lw) analysis to readily detect and monitor areas affected by thunderstorm outflow air are presented. A comparison between the delineation of thunderstorm-produced meso- or bubble highs by conventional pressure analysis and static energy analysis is made using the 15 May 1968 severe storm day as an example.

R. L. Livingston

Papers

Hourly Surface Static Energy Analysis as a Delineator of Thunderstorm Outflow Areas