![](\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/images\/2023\/02\/230211_himawari9_infrared_Cyclone_Freddy_anim.gif\")
<\/a>JMA Himawari-9 Infrared Window (10.4 \u00b5m) images [click to play animated GIF | MP4<\/strong><\/a>]<\/p><\/div>JMA<\/strong><\/a> Himawari-9 Infrared Window (10.4 \u00b5m) images (above)<\/strong><\/em> showed Cyclone Freddy in the South Indian Ocean as it was rapidly intensifying from a Category 1 to a Category 3 storm by 12 UTC on 11 February 2023 (JTWC discussion<\/strong><\/a>), eventually presenting a ragged eye for several hours — then briefly reaching Category 4<\/strong><\/a> intensity at 00 UTC on 12 February (SATCON<\/strong><\/a> | JTWC discussion<\/strong><\/a>). Overshooting tops within the eyewall of Freddy occasionally exhibited cloud-top infrared brightness temperatures of -90\u00baC and colder (yellow pixels embedded within darker purple regions).<\/p>\n A NOAA-20 VIIRS Day\/Night Band (0.7 \u00b5m) image valid at 1825 UTC on 11 February (below)<\/strong><\/em> showed the eye of Freddy.<\/p>\n NOAA-20 VIIRS Day\/Night Band (0.7 \u00b5m) image, valid at 1825 UTC on 11 February [click to enlarge]<\/p><\/div>Himawari-9 Infrared Window (11.2 \u00b5m) images from the CIMSS Tropical Cyclones<\/strong><\/a> site (below)<\/strong><\/em> include contours and streamlines of deep-layer (850-200 hPa) wind shear<\/strong><\/a>. The intensification of Freddy occurred in spite of this unfavorable environment of moderate to strong eaterly shear — however, the storm was moving over relatively warm water (with Sea<\/strong> Surface<\/strong> Temperature<\/strong><\/a> values around 29\u00baC).<\/p>\n JMA Himawari-9 Infrared Window (11.2 \u00b5m) images, with contours and streamlines of 850-200 hPa wind shear<\/p><\/div>\n RCM\/Radarsat-2 SAR winds at 1136 UTC on 11 February (source<\/strong><\/a>) are shown below — a maximum wind speed of 106 knots<\/strong><\/a> was indicated within the northeast quadrant.<\/p>\n<\/a><\/a>