Tropical Cyclone Predictions over Indian Seas: Super Storm Phailin and beyond

The Indian seas- Bay of Bengal and the Arabian Sea- are impacted by only 5-6 tropical cyclones each year. However, the sub-continent accounts for the highest number of cyclone related fatalities globally. Of the 23 recorded deadly storms (>10,000 fatalities over last 300 years), 20 cyclones were formed over the Bay of Bengal. As seen in the case of Super Storm Phailin, improved numerical guidance over the Indian region have the potential to save lives and minimize property damages. NOAA's Global Forecasting System, the HWRF system and the NCAR-ARW model with data assimilated over land are now being routinely used for providing guidance. Indeed with the application of improved higher resolution models we are starting to see some significant reduction in the mean track errors (about 8-24%) in the recent years. Particularly, high resolution models are found to be better for recurving storms. Also, largly due to sustained interactions between NOAA and Ministry of Earth sciences and partnering research institutions in India, NOAA's HWRF modeling system was implemented in India. Based on mean statistics of 27 forecast cases of five recent very severe cyclones, the performance of HWRF model over Bay of Bengal is superior, particularly, for intensity prediction and can be attributed to the advanced vortex relocation and initialization procedure. The HWRF model showed 15 knots error for 12 – 72 hour forecast lengths. HWRF model captures the rapid intensification of the TC Giri before landfall, amongst several other storms, while other models fail to predict. The track forecast errors vary between 85 – 150 km for the same forecast lengths. We will present the state-of-the art in TC predictions over Indian seas with particular emphasis on the prediction of very severe cyclonic storm (VSCS) Phailin