sentences:  During that day Nancy started to rapidly intensify becoming a Severe Tropical Cyclone late on February 13 as a small, irregularly shaped, eye had begun to develop.The next day both RSMC Nadi, and the JTWC reported that Cyclone Nancy had attained its peak intensity of 175 km/h (110 mph 10-minute winds) and 230 km/h (145 mph 1-minute winds).Increasing wind shear then caused Nancy to weaken.