https://phys.org/news/2018-08-nasa-compact-center-hurricane-hector.html

The Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard Aqua provided that infrared data on Aug. 3 at 5:50 a.m. EDT (0950 UTC). MODIS data showed the strongest thunderstorms were as cold or colder than minus 70 degrees Fahrenheit (minus 56.6 degrees Celsius). NASA research indicates very cold cloud tops with the potential to generate very heavy rainfall.

The compact center was confirmed by the National Hurricane Center or NHC in their advisory on Aug. 3 at 5 a.m. EDT (0900 UTC) when they noted "Hurricane-force winds extend outward up to 15 miles (30 km) from the center and tropical-storm-force winds extend outward up to 70 miles (110 km)."