https://phys.org/news/2018-07-nasa-well-organized-typhoon-maria.html

NASA's Aqua satellite passed over Maria on July 9 at 2:29 a.m. EDT (0629 UTC) and analyzed the storm in infrared light. Infrared light provides temperature data and that's important when trying to understand how strong storms can be. The higher the cloud tops, the colder and the stronger they are.

AIRS found coldest cloud top temperatures in a wide and powerful band of thunderstorms around the storm's 30 nautical-mile-wide eye. Those 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.