![\"JMA](\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/images\/2021\/04\/210415_himawari8_infrared_Surigae_anim.gif\")
<\/a>JMA Himawari-8 Infrared Window (10.4 \u00b5m)<\/em> images [click to play animation | MP4<\/strong><\/a>]<\/p><\/div>2.5-minute interval rapid scan JMA<\/strong><\/a> Himawari-8 Infrared Window (10.4 \u00b5m) images (above)<\/strong><\/em> revealed intermittent cloud-top infrared brightness temperatures of -100\u00baC and colder (red pixels embedded within yellow-to-black inner cores)<\/em> — with the coldest being -101.7\u00baC at 1342 UTC<\/strong><\/a> — within the Central Cold Cover (CCC) pattern of Tropical Storm Surigae on 15 April 2021.<\/p>\n A zoom-in of NOAA-20 VIIRS Infrared Window (11.45 \u00b5m) imagery at 1644 UTC as viewed using RealEarth<\/strong><\/a> (below)<\/strong><\/em> also showed 2 clusters of red -100\u00baC and colder pixels, with a minimum of -103.6\u00baC (incidentally, the coldest pixels on the 1644 UTC Himawari-8 Infrared image were -96\u00baC). About an hour and 15 minutes after this NOAA-20 image, Surigae was upgraded to a Category 1 typhoon (the first typhoon of the 2021 season in the West Pacific basin).<\/p>\n NOAA-20 VIIRS Infrared Window (11.45 \u00b5m)<\/em> image at 1644 UTC [click to enlarge]<\/p><\/div>A plot of 12 UTC rawinsonde data<\/strong><\/a> from Yap Island showed that the coldest air temperature was -84.7\u00baC at 100 hPa (16.7 km) — so an overshooting top of -100\u00baC or colder indicated a significant vertical ascent above the tropopause.<\/p>\n<\/a>