138 The distinction of environments conducive to different types of severe weather across Central Europe

Thursday, 6 November 2014
Capitol Ballroom AB (Madison Concourse Hotel)
Tomas Pucik, European Severe Storms Laboratory, Wessling, Germany; and P. Groenemeijer, D. Ryva, and M. Kolar

We studied several environmental parameters (indices) and their ability to discriminate between no severe, severe and extremely severe categories that we defined for each severe weather type (tornado, large hail, severe wind gust, hevay rain). The severe weather reports were obtained from ESSL's European Severe Weather Database. The parameters (indices) were calculated from 1962 proximity soundings that were associated with at least two lightning detections by the EUCLID network, which we acquired for 4 years of thunderstorm activity (2008-2011).

For each severe weather type, we evaluated which parameters differentiate best between the intensity categories using non-parametric statistical tests, namely Mann-Whitney U-test and Kruskal-Wallis test. We evaluated whether and how well the parameters / indices differentiate between the intensity categories of individual severe weather threats.

We found that for hail severity discrimination, buoyancy related parameters attained the best scores, whereas wind profile-related parameters performed better for severe wind events. However, for both of them, the combination of CAPE and Deep Layer Shear (bulk 0-6 km shear) performed even better. This was different for excessive precipitation for which low-level moisture and the depth of the warm cloud layer were the best predictors. In case of tornadoes, the vertical wind profile is more relevant than paramaters related to buoyancy.

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