Multiple pyrocumulonimbus clouds produced by the East Troublesome Fire in Colorado

October 21st, 2020 |

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), “Clean” Infrared Window (10.35 µm, bottom left) and Fire Temperature RGB (bottom right) [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), “Clean” Infrared Window (10.35 µm, bottom left) and Fire Temperature RGB (bottom right) [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm), “Clean” Infrared Window (10.35 µm) and Fire Temperature Red-Green-Blue (RGB) images (above) showed a period of extreme behavior of the East Troublesome Fire in Colorado around and just after sunset on 21 October 2020. This rapidly-growing wildfire produced a series of pyrocumulonimbus (pyroCb) clouds — the coldest pyroCb cloud-top 10.35 µm infrared brightness temperatures were -65.1ºC (darker green enhancement). The hottest Shortwave Infrared brightness temperatures within the fire’s large thermal anomaly were 138.7ºC — which is the saturation temperature of 3.9 µm detectors on the ABI instrument of GOES-16.

=====22 October Update =====

A time-matched comparison of Shortwave Infrared images from Suomi NPP VIIRS (3.74 µm) and GOES-16 ABI (3.9 µm), valid at 0839 UTC on 22 October, is shown below. The finer spatial resolution of VIIRS (375 meters at nadir, vs 2 km for ABI) provided a more accurate depiction of the location of hottest fire pixels at that time. Note the amount of northwestward parallax shift of the cold (dark blue to violet) high clouds on the GOES-16 image.

Shortwave Infrared images from Suomi NPP VIIRS (3.74 µm) and GOES-16 ABI (3.9 µm), valid at 0839 UTC [click to enlarge]

Shortwave Infrared images from Suomi NPP VIIRS (3.74 µm) and GOES-16 ABI (3.9 µm), valid at 0839 UTC [click to enlarge]

During the subsequent daytime hours, GOES-16 Visible, Shortwave Infrared, Infrared Window and Fire Temperature RGB images (below)  showed another series of pyroCb clouds that were produced by the East Troublesome Fire — but not to the extent that was seen on 21 October. By early evening, the total burned area had increased to 170,163 acres (and was only 5% contained).

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), “Clean” Infrared Window (10.35 µm, bottom left) and Fire Temperature RGB (bottom right) [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), “Clean” Infrared Window (10.35 µm, bottom left) and Fire Temperature RGB (bottom right) [click to play animation | MP4]

Two high-resolution views of some of the pyroCb clouds and the fire’s thermal anomaly were provided by VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images from NOAA-20 at 1904 UTC and Suomi NPP at 1956 UTC (below).

VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

Additional satellite imagery of this fire event is available on the Satellite Liaison Blog.

===== 23 October Update =====

GOES-16 True Color images [click to play animation | MP4]

GOES-16 True Color RGB images [click to play animation | MP4]

GOES-16 True Color RGB images created using Geo2Grid (above) revealed the light brown hue associated with smoke from the East Troublesome Fire, which was being transported eastward across the North Atlantic Ocean; the large cloud field of Hurricane Epsilon could also be seen southwest of the smoke pall. The bulk of this smoke pall was being transported along a cold frontal boundary (below).

GOES-16 CIMSS Natural Color RGB images [click to play animation | MP4]'

GOES-16 CIMSS Natural Color RGB images [click to play animation | MP4]

Hurricane Epsilon

October 21st, 2020 |

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

Hurricane Epsilon underwent rapid intensification (ADT | SATCON) on 21 October 2020 — and 1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed Epsilon as it intensified from a  Category 1 to a Category 3 storm.

GOES-16 Mid-level Water Vapor (6.9 µm) images with plots of Derived Motion Winds from CIMSS Tropical Cyclones site (below) displayed the broad upper-level anticyclonic outflow north of the hurricane.

GOES-16 Mid-level Water Vapor(6.9 µm) images, with plots of Derived Motion Winds [click to enlarge]

GOES-16 Mid-level Water Vapor (6.9 µm) images, with plots of Derived Motion Winds [click to enlarge]

NUCAPS Sounding profiles surrounding Colorado’s East Troublesome Fire

October 21st, 2020 |

NOAA-20 NUCAPS Profiles over Colorado, at locations indicated, at ca. 1900 UTC on 21 October 2020 (click to enlarge)

The East Troublesome Fire in Colorado expanded greatly on 21 October (click here for more information), and produced pyrocumulus clouds.  NOAA-20 overflew the fire at around 1930 UTC (linked-to overpass map from this site) on 21 October, and NUCAPS profiles, shown above, diagnosed the stability of the mid- and upper-troposphere.  The toggle below between the NOAA-20 VIIRS Visible (0.64 µm) and Infrared (11.45 µm) imagery and NUCAPS Sounding availability points show the relationships between cloudiness and point color.

Suomi NPP Visible (0.64 µm) and Infrared (11.45 µm) imagery at 2015 UTC on 21 October 2020, as well as (NOAA-20) NUCAPS Sounding availability points at ~1900 UTC on 21 October (Click to enlarge)

Gridded NUCAPS fields, below, of 500-300 mb lapse rates show very weak stability in and around the fire location.  A fire-driven updrafts in the region would not find much in the way to impede its vertical development.

NUCAPS estimates of upper-tropospheric (500-300 mb) lapse rates at ca. 1900 UTC on 21 October 2020 (Click to enlarge)