Cameron Peak Fire becomes the largest on record for Colorado

October 14th, 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 diurnal changes in the Cameron Peak Fire in northern Colorado on 14 October 2020. Aided by strong westerly winds at the surface (with peak gusts in the 50-70 mph range), the fire’s thermal signature initially began to increase in areal coverage and spread rapidly eastward — however, following the passage of a cold front around 18 UTC, an influx of cooler air with higher relative humidity halted this eastward expansion of the fire (with the thermal signature then retreating westward and diminishing in size). By that evening, the fire’s total burned area had grown to 158,300 acres, making it Colorado’s largest wildfire on record. While there was some pyrocumulus development over the fire source region, this large and hot fire did not produce a pyrocumulonimbus cloud.

Another view of the fire using 5-minute imagery from GOES-16 provided quantitative products such as Fire Power, Fire Temperature and Fire Area (below) — these 3 products are components of the GOES Fire Detection and Characterization Algorithm (FDCA). Surface observations showed that during the morning hours smoke was restricting surface visibility to 3 miles at Fort Collins (KFNL) and 5 miles at Greeley (KGXY).

GOES-16 Fire Temperature (top left), Shortwave Infrared (3.9 µm, top right), Fire Power (bottom left) and Fire Area (bottom right) [click to play animation | MP4]

GOES-16 Fire Temperature (top left), Shortwave Infrared (3.9 µm, top right), Fire Power (bottom left) and Fire Area (bottom right) [click to play animation | MP4]

GOES-16 True Color Red-Green-Blue (RGB) images created using Geo2Grid (below) indicated that one portion of the Cameron Peak Fire smoke plume was transported eastward across parts of Nebraska and Iowa, with another part of the plume moving southeastward across Kansas.

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

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

A toggle between Terra MODIS True Color and False Color RGB images on 14 October from the MODIS Today site (below) showed the  Cameron Peak Fire smoke plume as well as its large burn scar (shades of red).

Terra MODIS True Color and False Color RGB images on 14 October [click to enlarge]

Terra MODIS True Color and False Color RGB images on 14 October [click to enlarge]

In a comparison of MODIS False Color RGB images from Aqua on 13 October and Terra on 14 October (below) the growth of the Cameron Peak Fire along its southeast flank was evident — and several other large fire burn scars were evident across Colorado and southern Wyoming.

MODIS False Color RGB images from Aqua (13 October) and Terra (14 October) [click to enlarge]

MODIS False Color RGB images from Aqua (13 October) and Terra (14 October) [click to enlarge]

Additional aspects of this fire and its environment are discussed here.

Outbreak of severe thunderstorms across the Deep South

April 12th, 2020 |

GOES-16 "Red" Visible (0.64 µm) images [click to play animation | MP4]

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

A major outbreak of severe thunderstorms (SPC Storm Reports) occurred across the Deep South on 12 April 2020. 1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the development and propagation of deep convection during the 1200-2359 UTC period. The corresponding GOES-16 “Clean” Infrared Window (10.35 µm) images are shown below.

GOES-16

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

Some of the strongest long-track tornadoes occurred in southern Mississippi — a closer view of GOES-16 Visible, Infrared and Visible/Infrared Sandwich Red-Green-Blue (RGB) images (below) revealed the pulsing nature of overshooting tops — which exhibited cloud-top infrared brightness temperatures as cold as -77ºC at 2038-2039 UTC, about 35 minutes prior to the destructive tornado that moved through Bassfield — and well defined “enhanced-v” signatures were apparent in the Infrared and RGB imagery, with that signature’s warm wake immediate downwind (east) of the overshooting tops indicating the likely presence of Above-Anvil Cirrus Plumes.

GOES-16 "Red" Visible (0.64 µm ), "Clean" Infrared Window (10.35 µm), and Visible/Infrared Sandwich RGB images [click to play animation | MP4]

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

GOES-16 "Red" Visible (0.64 µm) images, with time-matched SPC Storm Reports plotted in red [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images, with time-matched SPC Storm Reports plotted in red [click to play animation | MP4]

1-minute GOES-16 Visible images (above) and Infrared images (below) include plots of time-matched SPC Storm Reports.

GOES-16 "Clean" Infrared Window (10.35 µm) images, with time-matched SPC Storm Reports plotted in cyan [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with time-matched SPC Storm Reports plotted in cyan [click to play animation | MP4]

NOAA/CIMSS ProbSevere is a tool that could have been used during this outbreak to identify which radar cells were most likely to produce severe weather.  The image below, from here, shows the reports of severe weather, the warning polygons, and ProbSevere locations (a closer view of the Mississippi tornadoes can be seen here).

Severe weather reports from 12 April 2020 (Green: Hail; Blue: Wind; Red: Tornado), NWS Warning Polygons and ProbSevere locations (plotted as boxes when ProbSevere exceeded 50% (Click to enlarge)

===== 14 April Update =====

GOES-16

GOES-16 “Red” Visible (0.64 µm) and Normalized Difference Vegetation Index images [click to enlarge]

Southwest-to-northeast oriented tornado damage paths in southern Mississippi were evident in a toggle between GOES-16 Visible and Normalized Difference Vegetation Index (NDVI) images (above). NDVI values within the damage path were generally 0.6, compared to 0.7-0.8 in adjacent areas. According the the NWS Jackson storm survey, the maximum path width of the longest-track (~67 mile) EF-4 tornado that began near Bassfield was about 2 miles — the widest ever measured in Mississippi, and one of the widest tornado damage paths ever measured in the US.

In a toggle between Aqua MODIS NDVI and Land Surface Temperature (LST) images (below), LST values were 5-10ºF warmer — low 80s F, darker shades of red —  within the tornado damage path, compared to areas adjacent to the path.

Aqua MODIS Normalized Difference Vegetation Index and Land Surface Temperature images [click to enlarge]

Aqua MODIS Normalized Difference Vegetation Index and Land Surface Temperature images [click to enlarge]

The tornado damage paths were also apparent in a comparison of before (26 March) and after (14 April) Aqua MODIS True Color RGB images (below) from the MODIS Today site. Note that 2 smoke plumes were seen on the 26 March image.

Aqua MODIS True Color RGB images from 26 March and 14 April [click to enlarge]

Aqua MODIS True Color RGB images from 26 March and 14 April [click to enlarge]

True and False-color imagery from NOAA-20 (from this (temporary) website) also show the damage path.

True- and False-Color imagery from the afternoon NOAA-20 overpass on 14 April 2020 (Click to enlarge)

NOAA-20 True Color RGB imagery of the Mississippi EF-4 tornado damage path that had a maximum with of 2 miles is shown below, using RealEarth.

NOAA-20 VIIRS True Color RGB image, including county outlines and map labels [click to enlarge]

NOAA-20 VIIRS True Color RGB image, including county outlines and map labels [click to enlarge]

Multi-day outbreak of pyrocumulonimbus clouds across southeastern Australia

December 29th, 2019 |

Himawari-8 Shortwave Infrared (3.9 µm, top) and Longwave Infrared Window (10.4 µm, bottom) images [click to play animation | MP4]

Himawari-8 Shortwave Infrared (3.9 µm, top) and Longwave Infrared Window (10.4 µm, bottom) images [click to play animation | MP4]

JMA Himawari-8 Shortwave Infrared (3.9 µm) and Longwave Infrared Window (10.4 µm) images (above) showed a large bushfire (dark black to red pixels in the 3.9 µm imagery) in far southeastern Victoria, Australia — which quickly burned its way to the coast and produced 3 distinct pulses of pyrocumulonimbus (pyroCb) clouds on 29 December 2019. To be classified as a pyroCb, the deep convective cloud must be generated by a large/hot fire (in this case, the Cann River fire complex), and eventually exhibit cloud-top 10.4 µm infrared brightness temperatures of -40ºC and colder (assuring the heterogeneous nucleation of all supercooled water droplets to ice crystals).

The coldest cloud-top 10.4 µm infrared brightness temperature was -62.6ºC (darker green pixels) at 1650 UTC. According to rawinsonde data from Melbourne (below), this corresponded to an altitude near 13 km.

Plots of rawinsonde data from Melbourne, Australia [click to enlarge]

Plots of rawinsonde data from Melbourne, Australia [click to enlarge]

The long/narrow thermal anomaly of the hot bushfire — which burned southwestward all the way to the coast — was outlined in dark black pixels on VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP, as viewed using RealEarth (below).

w (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

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

===== 30 December Update =====

 Himawari-8 Shortwave Infrared (3.9 µm, top) and Longwave Infrared Window (10.4 µm, bottom) images [click to play animation | MP4]

Himawari-8 Shortwave Infrared (3.9 µm, top) and Longwave Infrared Window (10.4 µm, bottom) images [click to play animation | MP4]

A Himawari-8 Target Sector was positioned over southeastern Australia beginning at 2312 UTC on 29 December, providing images at 2.5-minute intervals — a comparison of Shortwave Infrared and Longwave Infrared Window imagery (above) revealed the formation of several additional pyroCb clouds as southeastern Victoria bushfires continued to grow in number and size. During the daytime, pyroCb cloud tops will appear warmer (darker gray) than those of conventional thunderstorms in the 3.9 µm imagery, due to enhanced reflection of solar radiation off the smaller ice crystals found in the pyroCb anvil. Development of the multiple deep convective pyroCb clouds on this day may have been aided by forcing for ascent provided by an approaching cold front and mid-tropospheric trough, along with favorable upper-tropospheric jet streak dynamics.

The coldest Himawari-8 cloud-top 10.4 µm brightness temperature on 30 December was -73.15ºC at 13:24:41 UTC (violet pixel near the coast); this was 5ºC colder than the coldest temperature of -68.1ºC  — at an altitude of 15 km — on 12 UTC rawinsonde data from Melbourne (below). During the 12-hour period between the 2 soundings, the coded tropopause ascended from a height of 13.1 km (-63.7ºC) at 00 UTC to 14.2 km (-67.5ºC) at 12 UTC.

Plots of rawinsonde data from Melbourne, Australia at 00 UTC (yellow) and 12 UTC (cyan) [click to enlarge]

Plots of rawinsonde data from Melbourne, Australia at 00 UTC (yellow) and 12 UTC (cyan) [click to enlarge]

In a toggle between VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP is shown (below), a large pyroCb cloud was seen moving eastward away from the bushfires.

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

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

===== 31 December Update =====

Suomi NPP VIIRS Day/Night Band, Shortwave Infrared, Near-Infrared & Active Fire Product images at 1455 UTC on 31 December (credit: William Straka, CIMSS) [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm), Shortwave Infrared (3.75 µm and 4.05 µm), Near-Infrared (1.61 µm and 2.25 µm) & Active Fire Product images at 1455 UTC on 31 December (credit: William Straka, CIMSS) [click to enlarge]

Suomi NPP VIIRS Day/Night Band, Shortwave Infrared, Near-Infrared & Active Fire Product images (above) showed nighttime signatures of the widespread bushfires across Victoria and New South Wales at 1455 UTC on 31 December (or 1:55 am local time on 01 January). In the town of Mallacoota, about 4000 people were forced to evacuate their homes and take shelter along the coast (media report). The surface air temperature at Mallacoota Airport briefly increased to 49ºC (120ºF) at 8:00 am local time as the fires approached (below).

A sequence of daily Aqua MODIS True Color RGB images with an overlay of VIIRS Fire Radiative Power showed the fires and smoke during the 29-31 December period (below).

Aqua MODIS True Color RGB images with an overlay of VIIRS Fire Radiative Power [click to enlarge]

Aqua MODIS True Color RGB images with an overlay of VIIRS Fire Radiative Power [click to enlarge]

A multi-day Himawari-8 GeoColor animation covering the period 28 December – 01 January is available here.

Lake-effect, river-effect and bay-effect cloud bands producing snowfall

November 13th, 2019 |

GOES-16

GOES-16 “Red” Visible (0.64 µm), “Clean” Infrared Window (10.35 µm) and Day Cloud Phase Distinction RGB images on 07 November [click to play animation | MP4]

During the course of multiple intrusions of arctic air across the Lower 48 states during early November 2019, a variety of lake-effect, river-effect and bay-effect cloud features were generated — many of which produced varying intensities of snowfall. GOES-16 (GOES-East) “Red” Visible (0.64 µm), “Clean:” Infrared Window (10.35 µm) and Day Cloud Phase Distinction Red-Green-Blue (RGB) images on 07 November (above) showed lake-effect clouds streaming south-southeastward across Lake Superior. The Day Cloud Phase Distinction RGB images (in tandem with the Infrared images) helped to highlight which cloud features had glaciated and were therefore more capable of producing moderate to heavy lake-effect snow; the dominant band yielded 5-10 inches of snowfall in the central part of northern Michigan.

On 11 November, GOES-16 Nighttime Microphysics RGB images (below) displayed lake-effect clouds originating from the still-unfrozen waters of Fort Peck Lake in northeastern Montana — these clouds did produce a brief period of light snowfall downstream at Glendive (KGDV). On this particular morning, the lowest temperature in the US occurred in north-central Montana, with -30ºF reported north of Rudyard.

GOES-16 Nighttime Cloud Phase Distinction RGB images on 11 November [click to play animation | MP4]

GOES-16 Nighttime Microphysics RGB images on 11 November [click to play animation | MP4]

On 12 November, cold air moving southward across the Lower Mississippi Valley produced horizontal convective roll clouds which were evident in GOES-16 Nighttime Microphysics RGB and subsequent Visible images after sunrise (below) — one of these narrow cloud bands was likely enhanced by latent heat fluxes as it passed over the comparatively-warm waters of the Mississippi River, and produced accumulating snowfall in downtown Memphis. Note that since Memphis International Airport KMEM was located just east of the cloud band, no accumulating snow was reported there (only a brief snow flurry around 1430 UTC).

GOES-16 Nighttime Microphysics RGB and "Red" Visible (0.64 µm) images on 12 November [click to play animation | MP4]

GOES-16 Nighttime Microphysics RGB and “Red” Visible (0.64 µm) images on 12 November [click to play animation | MP4]

Aqua MODIS Sea Surface Temperature values along parts of the Mississippi River were as warm as the mid-40s F (below).

MODIS Sea Surface Temperature product at 1848 UTC on 12 November; rivers are plotted in red [click to enlarge]

Aqua MODIS Sea Surface Temperature product at 1848 UTC on 12 November; rivers are plotted in red [click to enlarge]


On 13 November, as the cold air was moving off the US East Coast, GOES-16 Infrared images (below) revealed bay-effect cloud plumes which developed over Chesapeake Bay and Delaware Bay — the Chesapeake Bay plume produced brief periods of light snow at Oceana Naval Air Station in Virginia Beach KNTU from 06-10 UTC (and possibly contributed to snowfall farther south at Elizabeth City, North Carolina KECG).

GOES-16 "Clean" Infrared Window (10.35 µm) images on 12 November [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images on 12 November [click to play animation | MP4]

Terra MODIS Sea Surface Temperature values in Chesapeake Bay and Delaware Bay were in the lower to middle 50s F where the bay-effect cloud plumes were originating (below).

Terra MODIS Sea Surface Temperature product and Visible (0.65 µm) image at 1613 UTC [click to enlarge]

Terra MODIS Sea Surface Temperature product and Visible (0.65 µm) image at 1613 UTC [click to enlarge]