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Cyclone Narelle rapidly intensifies over the Coral Sea

By Scott Bachmeier •

2.5-minute Himawari-9 Infrared images, from 0602 UTC on 18 March to 0119 UTC on 19 March [click to play animated GIF | MP4]

2.5-minute Target Sector JMA Himawari-9 Infrared images (above) showed Cyclone Narelle as it was rapidly intensifying over the Coral Sea on 18 March 2026 — becoming a Category 2 storm by 1200 UTC, a Category 3 storm by 1800 UTC and a Category 4 storm by 0000 UTC (ADT | SATCON). The coldest cloud-top infrared brightness temperatures were in the -90 to -95C range.

Himawari-9 Infrared / Water Vapor Difference images (below) exhibited large difference values — highlighting significant overshooting tops.

Himawari-9 Infrared / water Vapor Difference images

Himawari-9 Infrared images with an overlay of Deep-Layer Wind Shear (below) indicated that Narelle was moving through an environment of modest shear — which, along with warm Sea Surface Temperatures favored further intensification.

Himawari-9 Infrared images, with an overlay of contours and streamlines of Deep-Layer Wind Shear at 1800 UTC on 18 March

DMSP-18 SSMIS Microwave image at 0622 UTC on 18 March

Comparing DMSP SSMIS Microwave images at 0622 UTC (above) and 2004 UTC (below), the eyewall became more consolidated and the eye diameter contracted a bit (signatures of an intensifying tropical cyclone).

DMSP-17 SSMIS Microwave image at 2004 UTC on 18 March

Categories: DMSP, Himawari-9, Microwave, Tropical cyclones