A Case Study of a Multicell Severe Convective Storm in Ankara, Turkey

A maximum wind gust speed of 79.3 kn was measured on 2 August 2011 at the Esenboğa International Airport (International Air Transport Association [IATA] code: ESB), which is located in Ankara, the capital of Turkey. This value is the highest maximum wind gust speed value measured at this airport over the last 60 years. At the time of this meteorological event, a thunderstorm with heavy rain (+TSRA) occurred, which reduced the runway visibility to 150 m. Total precipitation of 21.8 mm was measured during a 20-min period, and part of the apron was submerged. A multicellular severe convective storm (MSCS) caused this influential event. The purpose of this study is to investigate the meteorological conditions underlying this MSCS event. Synoptic and sounding reanalysis products obtained with the Weather Research and Forecasting (WRF) model (four nested domains were established with horizontal resolution of 27, 9, 3, and 1 km), in addition to satellite, radar, sounding, aviation routine weather report (METAR), selected aviation special weather report (SPECI), and automated weather observing system (AWOS) (on a minute basis) data obtained from the Turkish State Meteorological Service (TSMS), were analysed. During MSCS transition, the maximum radar-measured reflectivity value was 61.0 dBZ. Based on Stokes’ theorem, maximum runway divergence and convergence values of 15.0 × 10^–3 and 19.3 × 10^–3 s⁻¹, respectively, were calculated. As a result, it was found that compared to the low convective available potential energy (CAPE) value of 978.9 J kg⁻¹, the 0- to 6-km above-ground-level (AGL) deep layer shear was high, at approximately 40 kn.