A comparison of GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Cirrus (1.38 µm) and “Clean” Infrared Window (10.3 µm) images (above) revealed a number of aircraft contrails drifting eastward across Virginia during the morning hours on 18 December 2017. Note how many of the individual contrails were easier to identify and follow in the sequence of 1-minute interval Mesoscale Sector images.

A Cirrus band is also available on the MODIS instrument (aboard Terra and Aqua) as well as the VIIRS instrument (aboard Suomi NPP and NOAA-20) — a toggle between the Terra MODIS Cirrus (1.375 µm),  Infrared Window (11.0 µm) and Visible (0.65 µm) images at 1607 UTC (below) again showed that contrails and other ice crystal cloud features were better highlighted on the Cirrus image.

The 12 UTC rawinsonde profile from Washington Dulles Airport in northern Virginia (below) showed a relatively moist layer in the upper troposphere near the 300 hPa (9.5 km or 31,000 ft) level, which is a common altitude for commercial jets to fly — this likely contributed to the longevity of many of the contrail features.

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The Thomas Fire (InciWeb | Wikipedia) began to burn around 0226 UTC on 05 December 2017 (or 6:26 PM Pacific time on 04 December). By 17 December, the fire had burned 270,000 acres — the third largest wildfire on record in California — and caused 1 fatality. An animation of GOES-15 (GOES-West) Shortwave Infrared (3.9 µm) images (above) showed the evolution of the thermal signature (or “hot spots”, as depicted by darker black to yellow to red pixels) during the 0200 UTC 05 December to 0215 UTC 18 December time period. Besides the largest Thomas Fire, other smaller and more short-lived fires could also be seen — especially early in the period, when the Santa Ana winds were strongest (05-07 December blog post). Thick clouds moving over the region later in the period either attenuated or completely masked the thermal signatures, even though the fire was ongoing.

GOES-16 began transmitting imagery (from its GOES-East position at 75.2º W) at 1630 UTC on 14 December — a comparison of GOES-15 and GOES-16 Shortwave Infrared (3.9 µm) during the 14-17 December period (below) showed that in spite of the larger GOES-16 satellite view angle (62.6º, vs 43.2º for GOES-15), the improved spatial resolution (2 km vs 4 km at satellite sub-point) and improved temporal resolution (images every 5 minutes, with no 30-minute gaps due to Full Disk scans) provided a more accurate depiction of the fire trends and intensities.

In a comparison of 250-meter resolution Terra MODIS true-color and false-color Red-Green-Blue (RGB) images (source) at 1853 UTC on 17 December (below), minimal amounts of smoke and a lack of clouds allowed a good view of the large Thomas Fire burn scar (darker shades of reddish-brown) on the false-color image.

During the first full day of the fires on 05 December, a toggle between comparable Aqua MODIS true-color and false-color images (source) revealed very thick smoke plumes drifting southwestward over the adjacent offshore waters of the Pacific Ocean (below).

A toggle between 05 December Aqua MODIS and 17 December Terra MODIS false-color images (below) showed the northward and northwestward growth of the Thomas Fire burn scar.

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* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

The GOES-16 satellite finished its eastward drift from the initial check-out position at 89.5º West longitude, arriving at 75.2º West on 11 December 2017 — and should officially be declared the operational GOES-East satellite by 20 December. Shown here are some of the first GOES-16 images that began flowing on 14 December via GOES Rebroadcast (GRB) and the Satellite Broadcast Network (SBN): Full Disk Mid-level Water Vapor (6.9 µm) (above) and “Red” Visible (0.64 µm) (below).  Similar Full Disk animations of Lower-level (7.3 µm) and Upper-level (6.2 µm) Water Vapor images are available here and here.

Taking a closer look at the 15-minute Full Disk Visible imagery (below), smoke from wildfires burning in Southern California could seen moving a considerable distance to the southwest over the Pacific Ocean. Note that the smoke features became brighter toward sunset — this was due to a more favorable forward scattering geometry between the sun, the smoke and the satellite sensors.

Since the atmospheric column over that region of the Pacific was quite dry (as seen in the Water Vapor imagery), the Near-Infrared “Cirrus” (1.37 µm) images (below) were able to display a subtle signature of the smoke features — recall that the strength of the 1.37 µm spectral band is detection of particles that are efficient scatterers of light (such as cirrus ice crystals, volcanic ash, dust and smoke).

The 2 examples below show that GOES-16 CONUS sector coverage and resolution over the western US is still quite good (even with the large satellite viewing angle).

A multi-panel image featuring all 16 spectral bands of the GOES-16 ABI at 1537 UTC is shown below.

Realtime GOES-16 ABI imagery can be found at: https://www.ssec.wisc.edu/data/geo/#/animation?satellite=goes-16 and https://re.ssec.wisc.edu/s/QFMBi.

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The Thomas fire began burning in Southern California around 6:30 PM local time on 04 December (blog post) — and on 10 December 2017, GOES-15 (GOES-West) Shortwave Infrared (3.9 µm) images (above) revealed that the fire showed little signs of diminishing during the nighttime hours, and in fact began to exhibit a trend of intensification around 05 UTC or 9 PM local time. However, toward the end of the day on 10 December, bands of  thick cirrus clouds moving over the fire region acted to dramatically attenuate the satellite-detected thermal signature of the fire complex. Although the Santa Ana winds were not as intense as they had been during the previous week, some strong wind gusts were still observed.

A sequence of 4 Shortwave Infrared images from Terra MODIS and Suomi NPP VIIRS (below) showed the westward and northwestward expansion of the fire during the 0637 to 2032 UTC period. The Thomas fire has now burned 230,000 acres, making it the fifth largest wildfire on record in California.

In a toggle between Terra MODIS true-color and false-color Red-Green-Blue (RGB) images at 1846 UTC (below; source) the true-color image revealed a broad plume of thick smoke being transported westward and northwestward from the fire source region, while the false-color image showed the areal coverage of the burn scar (which appeared as reddish-brown hues beneath the clouds) as well as locations of the larger and more intense active fires (brighter pink to white) that were burning along the northern to western perimeter of the burn scar.

A comparison of Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images at 2032 UTC or 12:32 PM  local time (below) showed a well-defined thermal signature before the thicker cirrus clouds moved overhead from the south. A small cloud cluster (located just northwest of the fire thermal signature) exhibited a minimum infrared brightness temperature of -43ºC — if this cloud feature was indeed generated by the fire complex, it meets the -40ºC criteria of a pyrocumulonimbus cloud.

The fire was producing very thick smoke, in addition to deep pyrocumulus clouds (top photo taken around 1945 UTC or 11:45 AM local time):

Massive imposing smoke from #ThomasFire today. Looking west from Newbury Park. pic.twitter.com/gekRcWcPiO

— Greg Vit (@gvitty) December 10, 2017

#ThomasFire from Thousand Oaks yesterday. pic.twitter.com/DcvLdArGVC

— Art Oleszczuk (@_AutoArt) December 11, 2017

Shown below is a photo taken at 2045 UTC or 12:45 PM local time, from a commercial jet flying into Santa Barbara (courtesy of Henry Dubroff/www.pacbiztimes.com).

===== 11 December Update ===== 

A toggle between Suomi NPP VIIRS Day/Night Band (0.7 µm), Near-Infrared (1.61 and 2.25 µm), Shortwave Infrared (3.75 and 4.05 µm) and Infrared Window (11.45 µm) images at 1035 UTC or 2:35 AM local time (above; courtesy of William Straka, CIMSS) demonstrated how different spectral bands can be used to detect nighttime fire signatures. The maximum infrared brightness temperature on the 4.05 µm image was 389 K (115.9ºC or 240.5ºF). Note that the recently-launched JPSS-1/NOAA-20 satellite also carries a VIIRS instrument.

GOES-15 Shortwave Infrared (3.9 µm) images (below) showed that once the thicker bands of cirrus clouds moved northwestward away from the region, a more well-defined thermal signature became apparent.

A 7-day sequence Nighttime and Daytime composites of Suomi NPP VIIRS Shortwave Infrared (3.74 µm) images (source: RealEarth) is shown below — it illustrates the spread of the Thomas Fire from 05 December to 11 December. Hot infrared pixels are black, with saturated pixels appearing bright white.

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