Forecasting tropical cyclogenesis over ocean basins in the Northern Hemisphere

Understanding the role of tropical cloud clusters (TCC) in the development of tropical cyclones involves various complexities and, thus, necessitates precise research. The study on TC development from the TCCs is still minimal. The present research is carried out to investigate the predictability of Tropical cyclogenesis (TCG) by examining the Rossby Radius Ratio (RRR) and Daily Genesis Potential (DGP) of different cloud clusters over the four ocean basins in the Northern Hemisphere, viz., North Indian Ocean (NIO), North Atlantic Ocean (NAO), West Pacific Ocean (WPO), and East Pacific Ocean (EPO). The analysis of the TCC data, taken for the period 1996–2005, shows that both the predictors are skilled at identifying the developed and non-developed TCCs. The method of cumulative distribution is implemented to identify the threshold ranges of RRR and DGP. In addition, the forecast skill scores are estimated for the selected predictors. The rough set theory based on different condition-decision support is implemented to estimate the certainty in the TCG prediction scheme with each predictor individually and in combination. The result shows that higher certainty in TCG prediction is observed when RRR ≤ 24 and DGP ≥ 1.21 × 10−5 for the NIO basin. However, it is to be noted that the combination of both RRR and DGP provides better confidence in the predictability of TCG over the NAO basin (RRR ≤ 38 and DGP ≥ 0.71 × 10−5) and EPO basin (RRR ≤ 28.7 and DGP ≥ 0.47 × 10−5). Furthermore, RRR (threshold value ≤ 28.2) individually gives better predictability for TCG over the WPO basin. The forecasts of TCG with RRR and DGP are validated with the observations from 2006 to 2009.