90 Severe Weather Environments in Central Europe as characterized by proximity soundings

Wednesday, 5 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 have performed a study of environmental conditions related to severe convective weather using proximity soundings across central Europe, which, to our knowledge is the largest that has been carried out in Europe to date. Our study was done with forecasters in mind and our aim to help them to assess the risk of particular types of severe weather individually (hail, wind gusts, excessive precipitation, and tornadoes).

The full study consists of an analysis of 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. 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, acquired for 4 years of thunderstorm activity (2008-2011).

Our preliminary results include the following: we found an extremely high dependency of (extremely) severe hail probability on both CAPE and deep-layer shear. This contrasts with the rainfall risk that does increase with increasing CAPE, but is not evidently related to deep-layer shear. For heavy rainfall, however, high low level humidity has an additional predictive value to CAPE. The probability of severe wind gusts increases both with increasing CAPE and shear, but opposite to the extreme rainfall risk, low low-level humidity increases the wind threat. This effect is strongest in weak shear situations. Tornadoes become more likely as low-level shear increases, while their dependency on CAPE is low.

In our presentation we will present these and newer results and discuss where our results differ from previous studies performed in the USA. We will address the ways our results can be put to use in forecasting while mentioning their limitations.

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