Wind Shear and the Strength of Severe Convective Phenomena—Preliminary Results from Poland in 2011–2015

Abstract

Abstract:Severe convective phenomena cause significant loss in the economy and, primarily, casualties. Therefore, it is essential to forecast such extreme events to avoid or minimize the negative consequences. Wind shear provides an updraft-downdraft separation in the convective cell, which extends the cell lifetime. Wind shears between a few different air layers have been examined in all damaging convective cases in Poland, taken from the European Severe Weather Database between 2011 and 2015, in order to find their values and patterns according to the intensity of this phenomenon. Each severe weather report was assigned wind shear values from the nearest sounding station, and subsequently the presented summary was made. It was found that wind shear values differ between the given phenomena and their intensity. This regularity is particularly visible in shears containing 0 km wind. The highest shears occur within wind reports. Lower values are associated with hail reports. An important difference between weak and F1+ tornadoes was found in most of the wind shears. Severe phenomena probability within 0-6 km and 0-1 km shears show different patterns according to the phenomena and their intensity. This finding has its application in severe weather forecasting.

Observation and Real-Time Simulation of a Tornado Event in Hong Kong on 29 August 2018

“…e 0-1 km wind shear is comparable with the values reported in the literature (e.g. [6,11,12]), However, the wind shears of 0-3 km and 0-6 km are very small compared with those reported in the literature. e dynamic/thermodynamic parameters are also calculated from the 00 UTC radiosonde ascent.…”

“…e documentation hopefully would be useful for the analysis and forecast of tornado occurrence in Hong Kong in the future. In the analysis, parameters based on the sounding profiles such as wind shear [6] and Szilagyi Waterspout Index, WSI [7], would be considered.…”

The tornado of Talavera de la Reina on 3 September 1880

“…The 0-6 km bulk wind shear is used in severe convection researches (Monteverdi et al, 2003;Pilorz et al, 2016). This parameter is calculated by determining the difference in wind speed between the surface and at 6 km height (around 500 hPa).…”

“…Moreover, we have obtained a 0-6 km bulk wind shear value of roughly 4.7 m s -1 , which we acknowledge is also low. For example, it would be around the 25th percentile found by Pilorz et al (2016) for weak tornadoes recorded in Poland for the period 2011-2015. However, we highlight that the wind and shear in a particular place can undergo significant changes in minutes, which is hard to estimate for historical tornadoes.…”

Historical Winter Storm Atlas for Germany (GeWiSA)

“…The spatiotemporal extent of storm events greatly varies depending on the geographical location and the time during the year [2]. In Central Europe, storm events can roughly be classified into two categories: small-scale thunderstorms, which mainly occur from May to September [3][4][5][6], and large-scale winter storms mainly occurring from October to March, which are related to intense low-pressure systems [2,[7][8][9][10]. As a part of Central Europe, Germany was often hit by severe winter storms, causing total losses of about US$ 37bn and 300 fatalities since 1981 [1].…”