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Synoptic conditions of the derecho storm. Case study of the derecho event over Poland on August 11, 2017

Wrona Barbara, Mańczak Piotr, Woźniak Anna, Ogrodnik Michał, Folwarski Michał

Meteorology Hydrology and Water Management. Research and Operational Applications

2022

Vol. 10, Iss. 2

8--25

This study presents a comprehensive synoptic analysis of one of the most violent storms recorded in recent years in the northwestern part of Poland, which occurred on August 11, 2017. Its development took place ahead of a waving cold front in the tropical air mass, downstream of the upper-level trough. The thunderstorms formed over Lower Silesia in the afternoon and moved towards Gdańsk Pomerania to occur over the Baltic Sea after midnight on August 12, 2017, where they gradually disappeared. As the thunderstorms moved through this area, they ranged from single convective cells and unorganized multicell storms through supercell thunderstorms to mesoscale convective systems in the form of bow echo squall lines and the mesoscale convective vortex (MCV). The convective system, evolving over time, fulfilled the derecho criteria. Its development was related to the presence of both the upper and mid-level jet stream, which supported the formation of a strong rear inflow jet (RIJ) in the rear part of the convective system, being one of the main factors generating the formation of a bow echo squall line with strong wind gusts. The maximum wind gusts recorded on August 11, 2017, are among the highest in the history of Polish measurements and amounted to 42 m/s in Elbląg, 36 m/s in Chrząstów, 35 m/s in Gniezno, and around 30 m/s at several other stations.

Wind shear detection based on direct measurements, remote sensing and numerical models

Chaładyniak D., Jasiński J., Pietrek S., Krawczyk K.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

2016

nr 48 (120)

75--80

Wind has huge influence on take-off, landing and cruising of aircraft. Therefore measuring wind direction and speed as well as evaluating its structure are the most important tasks in meteorological support of flights. Wind shear, which is characterized by rapid changes of speed and/or direction, is one of the most hazardous phenomena for aviation. This phenomenon exists mostly in low tropospheric jet streams, areas of active atmospheric fronts, near convective clouds and strong temperature inversions. The paper proves that wind shear is mainly dependent on non-uniform layout of ascending and descending air currents and shows that this phenomenon can be detected by using ground sensors (ultrasonic anemometers), remote sensing methods (sodars, radars, wind profilers) and data from numerical mesoscale models.

Effects of wind shear on the atmospheric convective boundary layer structure and evolution

Fedorovich E., Conzemius R.

Acta Geophysica

2008

Vol. 56, no. 1

114-141

The article reviews past accomplishments and recent advances in conceptual understanding, numerical simulation, and physical interpretation of the wind shear phenomena in the atmospheric convective boundary layer.