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Cyclone Errol rapidly intensifies to Category 5 intensity off the coast of Western Australia

By Scott Bachmeier •

2.5-minute JMA Himawari-9 Red Visible (0.64 µm, left) and Clean Infrared Window (10.4 µm, right) images, from 2302 UTC on 15 April to 0942 UTC on 16 April [click to play animated GIF | MP4]

Target Sector (2.5-minute interval) JMA Himawari-9 AHI Red Visible (0.64 µm) and Clean Infrared Window (10.4 µm) images (above) showed Cyclone Errol as it was rapidly intensifying off the northern coast of Western Australia on 15-16 April 2025. About 2 hours after the end of the above animation, Errol peaked at 140 kts — Category 5 intensity — at 1200 UTC (SATCON). Errol exhibited a pinhole eye during the time period shown — a feature frequently observed with rapidly-intensifying tropical cyclones. Cloud-top infrared brightness temperatures in the eyewall region of Errol were in the -80s C (shades of violet to purple).

A NOAA-20 VIIRS Day/Night Band image valid at 0503 UTC (below) provided a higher-resolution view of the 10-mile diameter pinhole eye.

NOAA-20 VIIRS Day/Night Band (0.7 µm) image valid at 0503 UTC on 16 April [click to enlarge]

A Sentinel-1A Synthetic Aperture Radar (SAR) image (source) at 1610 UTC (below) sensed a maximum radial wind velocity of 124.8 knots in the northeast quadrant of Errol.

Sentinel-1A SAR image at 1032 UTC on 16 April [click to enlarge]

Factors favoring Errol’s rapid intensification included very warm water that the storm was traversing, and an environment of low deep-layer wind shear (below). Sea Surface Temperature and Wind Shear images were sourced from the CIMSS Tropical Cyclones site.

Plots of deep-layer wind shear centered on Errol, from 2100 UTC on 15 April to 1500 UTC on 16 April

Categories: Himawari-9, NOAA-20, SAR, Satellite winds, Tropical cyclones, VIIRS