Analyses of Convective Available Potential Energy (CAPE) and Convective Inhibition (CIN) in the Prediction of Thunderstorms over Nigeria

Thunderstorms, characterized by cumulonimbus clouds and precipitation, pose challenges for detection in operational models due to their small spatial and temporal scales. The study addresses the key challenges of the fine scales involved in convective initiation and the computational expense of processes involved in thunderstorm formation. This study investigates the predictability of convective initiation of thunderstorms, focusing on the relationship between Convective Available Potential Energy (CAPE) and Convective Inhibition (CIN). It aims to establish statistical relationships between CAPE, CIN, and thunderstorm occurrences in Lagos and Abuja, Nigeria. It also investigates and establishes the seasonal variation and relationships between the Predictor (CAPE and CIN) and thunderstorm frequency (response and predictand), and threshold values as a thunderstorm predictor in the study areas. This work made use of data extracted from synoptic observation records of Nigerian Meteorological Agency from 2003 to 2017 The surface based CAPE and CIN data used were obtained from ERA5, the fifth generation ECMWF reanalysis for the global climate and weather. The study found that the temporal trends of CAPE over the two stations were similar, but the trends of thunderstorm frequency differed. The frequency of thunderstorms declined during periods of increased CIN, giving way to monsoon rainfall and suppressed forms of thunderstorm. However, a stronger relationship and behavioral trend between CAPE and thunderstorm frequency was observed during the typical wet periods especially in Abuja which exhibits a distinct weather pattern. The study also found a strong disparity in the agreement between CAPE maxima months and the corresponding thunderstorm maxima months, indicating that the presence of CIN could hinder thunderstorm. These findings contribute to the understanding of the complex interactions between CAPE, CIN, and thunderstorm frequency, providing valuable insights for improving the predictability of convective initiation of thunderstorms.