County Fire in central California

July 1st, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and Shortwave Infrared (3.9 µm, right) images, with airport identifiers plotted in yellow [click to play animation | MP4]

The County Fire began burning in central California (northwest of Sacramento) around 2112 UTC or 2:12 pm local time on 30 June 2018 — GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) showed the smoke plume and thermal anomaly or “hot spot” (dark black to red pixels) of the fire during its initial 6.5 hours. Other features of interest in the imagery included reflection of sunlight from solar panel farms as seen here and here, as well as sun glint off the waters of the Sacramento River and the Sacramento-San Joaquin River Delta as seen here.

During the subsequent overnight hours, the thermal signature exhibited on GOES-16 Near-Infrared “Snow/Ice” (1.61 µm), Near-Infrared “Cloud Particle Size” (2.24 µm) and Shortwave Infrared (3.9 µm) images (below) revealed the rapid southward spread of the fire along the Napa/Yolo county line — the fire began in far western Yolo County, and eventually moved into far eastern Napa County. The smaller, less intense fire signature seen just to the northwest was that of the Pawnee Fire.

GOES-16 Near-Infrared

GOES-16 Near-Infrared “Snow/Ice” (1.61 µm, left), Near-Infrared “Cloud Particle Size” (2.24 µm, center) and Shortwave Infrared (3.9 µm, right) images, with airport identifiers plotted in yellow and Napa/Yolo County outlines plotted in blue [click to play animation | MP4]

A toggle between Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images (below) showed the thermal anomaly and bright glow of the County fire at 1043 UTC or 3:43 am local time. Due to ample illumination from the Moon (in the Waning Gibbous phase, at 90% of Full), the smoke plume could be seen drifting southwest over the adjacent waters of the Pacific Ocean — note the shadow cast by the smoke plume upon the fog/stratus deck immediately off the coast.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images, with surface reports plotted in cyan [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images, with surface reports plotted in cyan [click to enlarge]

A toggle between consecutive Suomi NPP VIIRS Day/Night Band (0.7 µm) images (below) showed the change in location of the smoke plume during the ~1 hour and 40 minutes separating the 2 satellite overpasses. The region was on the far western edge of the earlier swath. These images demonstrate the “visible image at night” capability of the VIIRS Day/Night Band.

Suomi NPP VIIRS Day/Night Band (0.7 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) images [click to enlarge]

The 00 UTC rawinsonde data from nearby Oakland (below) showed northeasterly winds at altitudes of 1500-2800 meters or 4900-9200 feet.

Plots of rawinsonde data from Oakland, California [click to enlarge]

Plots of rawinsonde data from Oakland, California [click to enlarge]

During the late morning and early afternoon of 01 July, the fire burn scar could be seen beneath the smoke plume on 250-meter resolution Terra and Aqua MODIS False Color Red-Green-Blue (RGB) images viewed using RealEarth (below).

Terra MODIS True Color and False Color RGB images [click to enlarge]

Terra MODIS True Color and False Color RGB images [click to enlarge]

Aqua MODIS True Color and False Color RGB images [click to enlarge]

Aqua MODIS True Color and False Color RGB images [click to enlarge]

===== 03 July Update =====

Landsat-8 False Color RGB image [click to enlarge]

Landsat-8 False Color RGB image [click to enlarge]

A 30-meter resolution Landsat-8 False Color RGB image (above) showed the areal extent of the County Fire burn scar on the morning of 03 July. Pink-colored pixels indicated hot signatures of actively-burning fires. The morning Incident Report listed the fire size at 70,000 acres and 5% containment.

Pyrocumulonimbus cloud from the Spring Fire in southern Colorado

June 27th, 2018 |

GOES-16

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

GOES-16 “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed the Spring Fire which began burning just west of La Veta Pass (station identifier KVTP) in south-central Colorado on 27 June 2018. The fire produced a small pyrocumulonimbus (pyroCb) cloud around 0100 UTC, which drifted slowly to the northeast. The 10.3 µm cloud-top infrared brightness temperature cooled below the -40ºC (lime green enhancement) pyroCb threshold.

===== 29 June Update =====

NOAA-20 VIIRS Day/Night Band (0.7 µm), Shortwave Infrared (3.75 µm and 4.05 µm) and Near-Infrared (1.61 µm and 2.25 µm) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm), Shortwave Infrared (3.75 µm and 4.05 µm) and Near-Infrared (1.61 µm and 2.25 µm) images [click to enlarge]

A nighttime comparison of NOAA-20 VIIRS Day/Night Band (0.7 µm), Shortwave Infrared (3.75 µm and 4.05 µm) and Near-Infrared (1.61 µm and 2.25 µm) images at 0852 UTC or 2:52 am MST on 29 June (above; courtesy of William Straka, CIMSS) showed the visible and thermal signatures of the Spring Fire. With ample illumination from the Moon (in the Waning Gibbous phase, at 98% of full), the hazy signature of smoke could be seen drifting northeastward past the Colorado/Kansas border.

Trail Mountain Fire in Utah

June 20th, 2018 |

GOES-16

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

GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) showed the smoke plume and thermal anomaly or “hot spot” (dark black to red pixels) associated with the Trail Mountain Fire in Utah on 20 June 2018. Once the smoke was lofted to higher altitudes (in 2 distinct pulses) it quickly fanned out southeastward toward the Utah/Colorado border, transported by northwesterly winds around the periphery of a ridge of high pressure that was building into the Southwest US.

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]