Tropical Storm Jova: very cold cloud top IR temperatures
GOES-15 10.7 µm IR images (click image to play animation)
GOES-15 10.7 µm IR images (above; click image to play animation) showed a large area of very cold cloud top IR brightness temperatures associated with Tropical Storm Jova over the East Pacific Ocean on 07 October 2011. Embedded within the large region of cloud top IR temperatures colder than -80º C (light purple color enhancement) were smaller areas that exhibited cloud top IR temperatures of -90º C or colder (dark purple color enhancement) — and the coldest cloud top IR brightness temperature seen was -94.65º C at 09:30 UTC. It is unusual to see cloud top IR brightness temperatures of -90º C or colder on 4-km resolution GOES IR imagery.
===== 10 October Update =====
A comparison of GOES-11 (GOES-West), GOES-15, and GOES-13 (GOES-East) visible channel images (below) showed the eye of Category 3 Hurricane Jova on 10 October 2011. Note how the difference in satellite viewing angle produces very different eyewall illumination characteristics.
GOES-11, GOES-15, and GOES-13 visible channel images
GOES-15 is scheduled to replace GOES-11 as the operational GOES-West satellite in December 2011.