Convective and non-convective wind gusts in Poland, 2001-2015

The main aim of the article is to present the climatology of the peak wind gust frequency in Poland caused by the impact of both atmospheric circulation and the presence of thunderstorm clouds. Nine meteorological stations for the measurement period of 2001-2015 were taken into account. Only SYNOP reports with a peak wind gust higher or equal to 15 m s-1 in thunderstorm and non-thunderstorm days are considered in this study. The results indicate that the highest threat in terms of frequency and strength of peak wind gusts due to convection occurs in July. In winter, thunderstorms are rare, but if they occur, about 80% of them produce wind gusts exceeding a threshold of 15 m s-1. Peak wind gusts in a non-thunderstorm days are the highest and the most frequent in January, and are at a minimum during summer. Comparing both types, peak wind gusts during days with a thunderstorm were on average stronger than those without an involved convection. This indicated that convection was an important factor in enhancing the strength of a wind gust. The highest value in our base was 34 m s-1, recorded in Kraków on 8th July 2015 within the occurrence of a severe thunderstorm, while the highest value in a day without a thunderstorm was 33 m s-1, recorded in Łódź on 31st January 2002.