PyroCumulonimbus cloud in Colorado

June 9th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, left), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.3 µm, right) images, with hourly plots of surface reports [click to play MP4 animation]

GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed the formation of a small pyroCumulonimbus (pyroCb) cloud spawned by the 416 Fire in southwestern Colorado on 09 June 2018. A Mesoscale Domain Sector was positioned over the region, providing images at 1-minute intervals.

On Shortwave Infrared imagery, the thermal anomaly or “hot spot” appeared as a large cluster of red pixels — and the top of the pyroCb cloud took on a darker gray appearance than nearby high-altitude ice crystal clouds (due to enhanced solar reflectance off the smaller ice crystals of the pyroCb anvil). On 10.3 µm imagery, cloud-top infrared brightness temperatures cooled to around -50ºC (bright yellow enhancement) as the pyroCb drifted northeastward.

NOAA-19 AVHRR Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images, with plots of 22 UTC surface reports [click to enlarge]

NOAA-19 AVHRR Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images, with plots of 22 UTC surface reports [click to enlarge]

On 1-km resolution NOAA-19 AVHRR Infrared Window (10.8 µm) imagery at 22:07 UTC (above), the minimum cloud-top brightness temperature was -53ºC — this temperature roughly corresponded to an altitude of 11.6 km according to 00 UTC rawinsonde data from Grand Junction, Colorado (below).

Plots of rawinsonde data from Grand Junction, Colorado [click to enlarge]

Plots of rawinsonde data from Grand Junction, Colorado [click to enlarge]