Cyclone Jasper in the Coral Sea
Target Sector (2.5-minute interval) JMA Himawari-9 AHI Clean Infrared Window (10.4 µm) images (above) showed the gradual development of a ragged eye with Cyclone Jasper as the storm moved southward across the Coral Sea on 07 December 2023. Intermittent convective bursts within the eyewall contained a few overshooting tops that exhibited infrared brightness temperatures around -90ºC (yellow pixels embedded within dark purple areas). The partially-fragmented structure of the eyewall was evident in a DMSP-17 SSMIS Microwave image at 0816 UTC (source) (above) and a RCM-1 Synthetic Aperture Radar wind speed image at 0807 UTC (source) (below). Himawari-9 Infrared Window (11.2 µm) images from the CIMSS Tropical Cyclones site (below) showed that Jasper was moving through an environment of low deep-layer wind shear — which, in addition to its motion across warm water (SST | OHC) favored continued intensification.Jasper was upgraded to Category 3 intensity at 1800 UTC (JTWC discussion) — and a DMSP-17 SSMIS Microwave image at 1927 UTC (above) as well as a RCM-3 SAR wind speed image at 1914 UTC (below) displayed a more organized eyewall structure. Jasper was subsequently upgraded to a Category 4 storm at 0000 UTC on 08 December (SATCON), as the satellite presentation of the eye improved in Himawari-9 Infrared images — and mesovortices within the eye were revealed in Visible images (below).