30-second imagery of rapidly intensifying Hurricane Polo — which eventually reached Category 5 intensity
Overlapping 1-minute Mesoscale Domain Sectors provided 30-second GOES-18 (GOES-West) Infrared Window images of Hurricane Polo (above) as it rapidly intensified from a Category 1 to a high-end Category 3 storm late in the day on 21 September 2026. An eye became apparent by the end of the animation (the overlapping Mesoscale Sectors ended at 0438 UTC on 22 September, when Sector 1 was re-positioned over the Southwest US).
Following the period of 30-second imagery, a single GOES-18 Mesoscale Sector provided 1-minute Infrared Window imagery for the remainder of the day on 22 September (below), as Polo continued to rapidly intensify to a Category 4 (at 0600 UTC) and then to a Category 5 hurricane (at 1200 UTC). It is interesting to note that as Polo was progressing toward its maximum intensity (at 1900 UTC), an Enveloped Eyewall Lighting Signature was evident in the concentration of GLM Flash Points (for example, at 1445 UTC or at 1637 UTC); however, this eyewall lightning then abruptly ended after about 1900 UTC. (The ~2 hour GOES-18 data outage and subsequent image degradation/striping was due to a NOAA firewall maintenance issue.)
In terms of central pressure — with a minimum of 892 hPa (SATCON) — Polo became the second-most intense hurricane on record in the East Pacific.
Within an hour of Polo reaching Category 5 intensity at 1200 UTC, a Synthetic Aperture Radar (SAR) image (below) from Canada’s RCM-3 satellite (source) depicted wind speeds as high as 144.37 knots in the NW quadrant of the hurricane.
Products from the CIMSS Tropical Cyclones site showed two factors that were favorable for Polo’s rapid intensification on 22 September: (1) moving through an environment of low to moderate vertical wind shear (0900 UTC | 1800 UTC), and (2) traversing warm water (Sea Surface Temperature | Ocean Heat Content).
