Herold (was 22S) – Southern Indian Ocean

Mar. 20, 2020 – NASA Finds Herold a Fading Ex-Tropical Cyclone

Former Tropical Cyclone Herold is now a fading area of low-pressure in the Southern Indian Ocean and NASA’s Aqua satellite provided forecasters with a visible image.

Aqua image of Herold
On Mar. 20, 2020, the MODIS instrument that flies aboard NASA’s Aqua satellite provided a visible image ex-tropical cyclone Herold in the Southern Indian Ocean. Credit: NASA Worldview

On Mar. 19 at 4 p.m. EDT (2100 UTC), the Joint Typhoon Warning Center issued their final bulletin on Herold. At that time, Herold’s center was located near latitude 26.6 degrees south and longitude 73.0 degrees east, approximately 948 nautical miles east-southeast of Port Louis, Mauritius. Herold’s maximum sustained winds at the time were near 30 knots (34.5 mph/55.5 kph) making it a tropical depression. It has since weakened.

On Mar. 20, the Moderate Resolution Imaging Spectroradiometer or MODIS instrument that flies aboard NASA’s Aqua satellite provided a visible image of the clouds circling Herold’s center. The clouds appeared wispy and devoid of heavy rainfall. The storm showed no strong convection (rising air that forms the thunderstorms that make up a tropical cyclone). Herold has moved over cooler waters which have sapped thunderstorm development.

Herold is expected to dissipate later in the day on Mar. 20.

NASA’s Aqua satellite is one in a fleet of NASA satellites that provide data for hurricane research.

Tropical cyclones/hurricanes are the most powerful weather events on Earth. NASA’s expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

By Rob Gutro
NASA’s Goddard Space Flight Center