Environment of severe storm formations over West Africa on the 26-28 June 2018

Meteorological applications

article

Marian Amoakowaah Osei¹  Jeffrey N. A. Aryee¹  Jacob Agyekum¹  Jesse Ashong⁵  Samuel Owusu Ansah⁵  Maureen Abla Ahiataku⁵  Frank Baffour-Ata⁶  Leonard K. Amekudzi¹  Winifred Ayinpogbilla Atiah¹  Michael Padi⁷  Johnson Ameho⁷  Bashiru Yahaya⁵  Joseph Portuphy^1,10  Benjamin Lamptey^1,10 

[1] Department of Meteorology and Climate Science, Kwame Nkrumah University of Science and Technology;Centre for Ecology and Hydrology;School of Earth and Environment, University of Leeds;Water Research Institute, Centre for Scientific and Industrial Research;Department of Hydrometeorology;Department of Environmental Science, Kwame Nkrumah University of Science and Technology;Safety Department, Air Navigation Service;Complexity and Climate-Leibniz Center for Tropical Marine Research;Department of Earth Sciences, Jacobs University;Department of Hydrometeorology, Ghana Meteorological Agency

关键词: atmospheric convection;    boundary layer dynamics;    GCRF African SWIFT;    gravity waves;    mesoscale convective systems;   

DOI  :  10.1002/met.2109

学科分类：社会科学、人文和艺术（综合）

来源: Wiley

【 摘 要 】

Understanding the environmental evolution of mesoscale convective systems (MCSs) is critical for forecasting weather in West Africa. This study investigated the thermodynamic and synoptic environments of MCSs over West Africa on 26 (storm 1) and 28 (storm 2) June 2018. Primary datasets used to assess the diurnal evolution of the storms were obtained from ERA5. The results showed a trapped gravity wave, enhanced by a well-established African Easterly Jet and monsoon trough, was responsible for the initiation of storm 1. Both storms also initiated in the presence of several moist lower (925–850 hPa) to mid-tropospheric (600 hPa) cyclonic and anticyclonic vortices, controlling inland moisture advection. The lower troposphere was moistened through moisture advection by the West African westerly jet for storm 1 and the nocturnal low-level jet prior to initiation for storm 2. For both storms, the evolution of outgoing longwave radiation showed a consistent atmosphere of deep afternoon convection. Boundary layer height increased significantly during storm evolution to support the increasing ascent of warm air. Vegetation cover differences may have also likely aided the evolution of storm 2. The passage of gravity waves from decaying storms can aid forecasters to nowcast likely regions of afternoon convection with high accuracy. Under the GCRF African Science for Weather Information and Forecasting Techniques (SWIFT), these findings are crucial in fulfilling the project's aims of improving weather forecasting capability and communication over West Africa.

【 授权许可】

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