Typhoon Ragasa
Over the last 48-hours, Typhoon Ragasa barreled through the South China Sea and its forecasted to make landfall in the Guangdong Province of China by 24 September 2025. Chinese megacities like Hong Kong and Macao reside along the coastline of the Guangdong Province, and have been put on high alert of the incoming storm. Typhoon Ragasa has already battered the northern Philippines producing significant rainfall, flooding, and high winds that led to widespread damage to infrastructure and also triggered landslides.
Himawari-9, a geostationary satellite operated by the Japan Meteorological Agency, provides observations of the typhoon at a high temporal refresh rate of every 10 minutes (i.e., Full Disk sector). The Himawari-9 AHI GeoColor product animation captures the cyclone offshore, south of Hong Kong, and moving westward towards the Chinese coastline from ~16-19Z, 23 September 2025. During the nighttime, GeoColor not only monitored the massive typhoon and observed its well defined eye, but the product also consists of a static, background city lights layer that helps viewers identify the populated areas that may be impacted by the storm.
Himawari-9 AHI GeoColor Product from 1600-1850Z, 23 September 2025
The Advected Layer Precipitable Water (ALPW) product, derived from multiple polar-orbiting satellites, captured the horizontal moisture transport of Ragasa over a ~30 hour period, as the typhoon trekked westward over the South China Sea. Refer to the ALPW animation below. The 4-panel product depicts precipitable water values within four atmospheric layers: from the surface to 850-mb (top-left), 850-700mb (top-right), 700-500mb (bottom-left), and 500-300mb (bottom-right). Note, the center of the typhoon can be spotted in the surface to 850mb precipitable water layer. The high moisture transport lead to torrential rainfall and flooding over southern China as Ragasa made landfall.
ALPW Product observations from 5Z, 22 September 2025 to 13Z, 23 September 2025
At ~9Z, 24 September 2025, Typhoon Ragasa made landfall near Hailing Island, China. VIIRS imagery from JPSS polar-orbiting satellites observed the typhoon as it moved towards the Chinese coastline prior to landfall. The infrared imagery is at a 375-m spatial resolution and shows the evolution of the typhoon, the typhoon’s eye and the convective bands.
VIIRS 11.45 um (I-5 Band) from ~5Z, 23 September 2025 to ~6Z, 24 September 2025