Super Typhoon Champi passes just south of Guam
2.5-minute Target Sector JMA Himawari-9 Infrared Window images (above) showed Super Typhoon Champi as its pinhole eye moved just south of Guam on 17 October 2026. The images included hourly plots of surface wind barbs and gusts (in knots) for Guam International Airport (PGUM, located near the center of the island) and Andersen Air Force Base (PGUA, located near the northern end of the island) — the peak wind gust at PGUM was 72 knots (at 2018 UTC), while the peak wind gust at PGUA was 59 knots.
The pinhole eye of Champi was also apparent in a DMSP-18 SSMIS microwave image at 1859 UTC (below), just south-southwest of Guam.
Champi was moving through an environment of low wind shear (below), and traversing warm water (Sea Surface Temperature | Ocean Heat Content) — factors which were favorable for the tropical cyclone to maintain Super Typhoon intensity.
After sunrise on 17 October, 2.5-minute Himawari-9 Visible images (below) revealed low-altitude mesovorticies within the pinhole eye of Champi. In addition, an interesting packet of gravity waves was propagating northwestward toward the southern semicircle of Champi.
This packet of gravity waves apparently perturbed the cloud tops south of the eye, with warmer cloud-top infrared brightness temperatures (IRBTs) in the vicinity of the waves, and colder IRBTs in advance of the waves — best seen in a toggle between the Himawari-9 Visible and Infrared Window images at 0007 UTC on 18 October (below). Since this author is unable to provide a science-based explanation of these waves and their effect on Champi’s cloud top, the blog post earns its place in the coveted “What the heck is thus?” category.