Performance assessment of WRF model in simulating the very severe cyclonic storm “TITLI” in the Bay of Bengal: A case study

Abstract The present study has been conducted to assess the performance of the Weather Research and Forecasting – Advanced Research (WRF-ARW, hereinafter named as WRF) model in simulating the very severe cyclonic storm (VSCS) “Titli” which formed over the Bay of Bengal during 08–13 October, 2018. The simulated meteorological variables viz. 10-m wind vectors, surface latent heat flux, rainfall, track and intensity based on minimum sea level pressure (MSLP), maximum sustained surface wind (MSW) are assessed to evaluate the model performance. The results are compared with India Meteorological Department (IMD) observations along with verification analyses [FiNaL analysis (FNL)]. The model simulated 24- h accumulation of rainfall verification is carried out by using the Method for Object based Diagnostic Evaluation (MODE) tool of Model Evaluation Tool Version 8 (MET-V8). The various statistical skill scores obtained from the MODE clearly indicates that the overall performance of WRF model in predicting the rainfall is reasonably good, mainly at lower forecast length (36–60 hr). The intensity and spatial distribution of rainfall are well matched with the verified analysis as well as with the Tropical Rainfall Measuring Mission (TRMM) observations. The analysis of maximum latent heat flux in the region of strongest surface wind suggests that the circulation is maintained due to increased transport of heat and moisture from the ocean. The track error analysis shows more error during the model initialization, which gradually decreases with the advance of forecast time. Efficacy of the WRF model in simulating the tropical cyclone (TC) is very distinct from the present study.