Authors : Orimoloye Israel Ropo and Adefisan Elijah Adesanya
Abstract: The thunderstorms forecasting has been identified by many forecasters as an unusually difficult problem deserving of some special research attention. The study investigated the roles of Convective Instability (CI) Indices and Thermo-dynamical Parameter (SITP) on thunderstorms occurrences and hence, determined the threshold values of these SITPs necessary for thunderstorm and occurrences and used for short-range forecasting of thunderstorm occurrence over Kano, Nigeria. Daily upper air data and hourly significant weather for August and September in years, 2012 and 2013 obtained from the archive of Nigerian meteorology agency were used. The study uses the concept of “a 2×2 contingency table” for analysing thunderstorm occurrence and obtained some simple skill scores such as Accuracy (AC), Bias (B), Probability of Detection (POD), False Alarm Ratio (FAR), Probability of False Detection (POFD) and Success Ratio (SR). The study established that if CI between 925 and 850 mb pressure levels is ≥100 hpa–1 and CAPE is ≥2500 J/kg simultaneously, the probability of thunderstorm occurrence is 70%. It means that success ratio of a 2×2 contingency table is 68% and the accuracy is about 74% and the FAR is 29%. The result has finally shown that short range-range forecast of the occurrence of thunderstorm and squall line is possible with the availability of upper air data.
Orimoloye Israel Ropo and Adefisan Elijah Adesanya, 2018. Convective Instability Indices and Thermo-Dynamical Parameter for Forecasting Thunderstorms Occurrences over Kano, Nigeria. Research Journal of Applied Sciences, 13: 285-293.