https://phys.org/news/2018-06-nasa-strong-storms-tropical-depression.html

AIRS data showed coldest cloud top temperatures in thunderstorms flaring east of 05W's center were warming, indicating weakening. Coldest temperatures were as cold as minus 63 degrees Fahrenheit (minus 53 degrees Celsius). Storms with cloud top temperatures that cold have the capability to produce heavy rainfall.

Ewiniar never made landfall on Hainan Island, China as its center stayed just to the east of the island. The storm did make landfall in extreme southwestern Guangdong province. The Joint Typhoon Warning Center or JTWC noted that a clear low level circulation center remains present over the southern portion of the Leizhuo Peninsula.