The present study describes the active role of met-ocean parameters on the heavy flooding that occurred during July 2018 in the Kuttanad region, Kerala. The model-derived data as well as observations showed a high anomaly of wave height in July 2018 off Kerala was not correlated with local wind anomaly and indicated possible connection of wave anomalies to swell waves. The high period and high amplitude swell waves suggest a wave setup formation near shore for flooding intensification in the Kuttanad region. The wave observation at an open ocean location (AD09) also confirms the presence of high swell waves during the same period. Anomalous elevated non-tidal sea level was evident in the tide gauge data. The narrow opening at Thottappally, is not able to discharge the outflow of the heavy flood water and it is further complicated by the wave setup at the entrance caused by long period swell waves.

Tropical Cyclone Ockhi was an intense cyclone, with a peculiar and long track, in the Arabian Sea in 2017. It caused severe damage to coastal infrastructure and death of 282 people. Indian National Centre for Ocean Information Services (INCOIS) issued the Joint INCOIS-IMD (India Meteorological Department) bulletins on the Ocean State Forecasts (OSF) and alerts/warnings during Ockhi. Validation of the OSF from INCOIS using buoys reveals that the forecasts were in good agreement with the observations [average correlation 0.9, RMSE ${\le}$0.8 m (for larger waves), and scatter index ${\le}$25%]. Climatological analysis of Genesis Potential Index (GPI) suggests that the southeast Arabian Sea, where the TC-Ockhi was intensified, had all the favourable conditions for intensification during November/December. Moreover, it was found that four days before the genesis of Ockhi, the environmental vorticity and relative humidity were more favourable for the cyclogenesis compared to vertical wind shear and potential intensity. The intensification rate was rapid as experienced by earlier cyclones in this region. Also, the cyclone track closely matched the background tropospheric winds. The present study suggests that the forecasters should look into the background dynamic and thermodynamic conditions extensively in addition to multi-model guidance to better predict the genesis, intensity and track of the cyclones.

$\bf{Higlights}$

$\bullet$ In the Arabian Sea, during the TC-Ockhi, the forecasts of wave parameters from the model forced with bias-corrected ECMWF winds resulted in very good agreement with observations.

$\bullet$ Climatologically, TC-Ockhi region has large potential for the genesis and intensification of TC due to an enhanced low-level cyclonic vorticity and the reduction in vertical wind shear.

$\bullet$ During the TC-Ockhi period, low-level vorticity and mid-tropospheric relative humidity were the dominant contributing factors, which lead to an enhanced GPI in the Arabian Sea.

$\bullet$ TC-Ockhi also had rapid intensification in a similar fashion the earlier cyclones in this region behaved.

$\bullet$ There is no abnormality also in the TC-Ockhi track, as the TC-Ockhi track matches well with the background tropospheric flow.