Developing winter storm over Colorado

March 19th, 2020 |

GOES-16 Mid-level Water Vapor (6.9 um) images, with hourly plots of surface wind barbs and gusts (knots) [click to play animation | MP4]

GOES-16 Mid-level Water Vapor (6.9 um) images, with hourly plots of surface wind barbs and gusts (knots) [click to play animation | MP4]

As a winter storm began to organize over Colorado on 19 March 2020, GOES-16 (GOES-East) Mid-level Water Vapor (6.9 um) images (above) showed the developing  middle tropospheric cyclonic circulation across the Colorado/Kansas/Nebraska border area. Peak wind gusts included 60 mph in Colorado and Nebraska, and 62 mph in Kansas (WPC Storm Summary).

As a result of the strong winds, several areas of blowing dust were seen in GOES-16 “Red” Visible (0.64 um), Split Window Difference (10.3-12.3 um) and Dust Red-Green-Blue (RGB) images (below): (1) a well-defined plume that originated in southeastern Colorado and moved northeastward across western Kansas, (2) a smaller plume originating north/northwest of Lamar, Colorado which moved eastward toward the Colorado/Kansas border, (3) a small plume that originated over the burn scar from the 07 March “Beaver Fire” in the Oklahoma Panhandle, and (4) multiple narrow plumes of dust in the wake of a cold front that moved southeastward across the region late in the day (which reduced the surface visiblity to 2 miles in southwestern Kansas).

GOES-16

GOES-16 “Red” Visible (0.64 um), Split Window Difference (10.3-12.3 um) and Dust RGB images [click to play animation | MP4]

A NOAA-20 True Color RGB image as viewed using RealEarth (below) provided a more detailed view of the dust plume north of Lamar, Colorado as well as the longer plume which stretched from southeastern Colorado into western Kansas.

NOAA-20 True Color RGB image at 18:40 UTC [click to enlarge]

NOAA-20 True Color RGB image at 18:40 UTC [click to enlarge]

GOES-16 Visible images with plots of GLM Groups (below) revealed a few clusters of lightning associated with convective elements that were likely producing thundersnow across northeastern Colorado and near the Colorado/Nebraska border. Where warmer air was still present near the Colorado/Kansas border, a more longer-lived thunderstorm was producing rainfall at the surface.

GOES-16

GOES-16 “Red” Visible (0.64 um) images, with GLM Groups plotted in red and hourly surface weather type plotted in yellow [click to play animation | MP4]



===== 20 March Update =====

GOES-16 Day Cloud Phase Distinction RGB images [click to play animation | MP4]

GOES-16 Day Cloud Phase Distinction RGB images [click to play animation | MP4]

On the following day, GOES-16 Day Cloud Phase Distinction RGB images (above) showed the large swath of fresh snow cover (shades of green) produced by this storm as it moved northeastward across the Upper Midwest. Clouds persisted over much of eastern Colorado, masking the extent of the snow cover there.

===== 21 March Update =====

Landsat-8 False Color RGB image, with and without labels [click to enlarge]

Landsat-8 False Color RGB image at 1724 UTC, with and without labels [click to enlarge]

On 21 March, a decrease in cloudiness over eastern Colorado allowed much of the snow cover (shades of cyan) to be seen in a swath of 30-meter resolution Landsat-8 False Color imagery as viewed using RealEarth (above). The effects of terrain were evident, with a lack of snow cover seen in areas where downslope flow was prevalent during the winter storm.

The effect of snow cover on boundary layer cloud development

March 15th, 2020 |

GOES-16 Snow/Cloud Discrimination RGB images [click to play animation]

GOES-16 Snow/Cloud Discrimination RGB images, with hourly plots of surface wind barbs (knots) [click to play animation]

GOES-16 (GOES-East) “Snow/Cloud Discrimination” Red-Green-Blue (RGB) images (above) revealed a west-to-east oriented band of fresh snow cover (1-4 inches, shades of red) across central Illinois on 15 March 2020. With a low-level northeasterly flow of cold air across the region, boundary layer cumulus clouds began to develop as solar heating warmed the surface — but this cloud development was suppressed over deeper portions of the snow cover. These RGB images use “Red” Visible (0.64 µm) data as the Red component, and Near-Infrared “Snow/Ice” (1.61 µm) data as the Green and Blue components; bare ground appears as shades of cyan, with supercooled water droplet clouds appearing as brighter shades of white.

A sequence of VIIRS Snow/Cloud Discrimination RGB images from NOAA-20 and Suomi NPP (below) showed a closer look at the band of snow cover and its effect on modulating the afternoon development of cumulus clouds.

VIIRS Snow/Cloud Discrimination RGB images from NOAA-20 and Suomi NPP [click to enlarge]

VIIRS Snow/Cloud Discrimination RGB images from NOAA-20 and Suomi NPP [click to enlarge]

A 30-meter resolution Landsat-8 False Color RGB image viewed using RealEarth (below) provided a detailed view of the band of snow cover (shades of cyan) at 1622 UTC.

Landsat-8 False Color RGB image, with and without labels [click to enlarge]

Landsat-8 False Color RGB image, with and without labels [click to enlarge]

South Sandwich Islands volcanic and orographic cloud signatures

March 12th, 2020 |

GOES-16 Near-Infrared

GOES-16 Near-Infrared “Cloud Particle Size” (2.24 µm) images [click to play animation | MP4]

Even though the South Sandwich Islands are near the limb of the GOES-16 (GOES-East) view, Near-Infrared “Cloud Particle Size” (2.24 µm) images (above) were able to display a long volcanic plume (brighter shades of white) originating from Mount Michael on Saunders Island during the daylight hours on 12 March 2020. In addition, smaller/shorter volcanic plumes could also be seen originating from a few of the smaller islands just to the north of Saunders Island. The volcanic plumes were more reflective (brighter white) because they were comprised of smaller droplets compared to the expansive stratus/stratocumulus clouds over the South Atlantic Ocean.

The smaller cloud particles of the volcanic plume were also more efficient reflectors of incoming solar radiation, thus appearing warmer (darker shades of gray) in GOES-16 Shortwave Infrared (3.9 µm) images (below).

GOES-16 Shortwave Infrared (3.9 µm) images [click to play animation | MP4]

GOES-16 Shortwave Infrared (3.9 µm) images [click to play animation | MP4]

2 days later, southerly/southwesterly winds interacting with the rugged terrain of the islands created von Kármán vortex streets downwind (north-northeast) of some of the islands (especially Montagu Island, the largest of the South Sandwich chain) — VIIRS True Color Red-Green-Blue (RGB) images from NOAA-20 and Suomi NPP  as visualized using RealEarth (below) provided a detailed view of these vortices.

VIIRS True Color RGB images from NOAA-20 and Suomi NPP [click to enlarge]

VIIRS True Color RGB images from NOAA-20 and Suomi NPP [click to enlarge]

In spite of the lower spatial resolution and large satellite viewing angle, the von Karman vortices could also be seen in GOES-16 “Red” Visible (0.64 µm) images (below).

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]

 

Wildfire in the Oklahoma Panhandle

March 7th, 2020 |

GOES-16

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

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images along with 5-minute Fire Power and Fire Temperature products (which are components of the GOES Fire Detection and Characterization Algorithm (SHyMet | ATBD) showed the rapid northeastward run (as fast as 103 feet per minute) of the 13,000 acre “Beaver Fire” (also known as the “412 Fire”) in the Oklahoma Panhandle on 07 March 2020. An elevated thermal signature on Shortwave Infrared imagery first began to appear southwest of Beaver, OK around 1546 UTC  — and 3.9 µm infrared brightness temperatures eventually peaked around 139ºC. Maximum Fire Power and Fire Temperature values exceeded 3100 MW and 2900 K, respectively. Fire Warnings were issued, with residents of Beaver and Forgan being advised to evacuate as the fire rapidly approached. In Visible imagery, the dark signature of a long, narrow vegetation burn scar was evident — and pyrocumulus clouds were seen developing over the fire.


Extreme fire behavior was aided by anomalously-strong winds across the southern Plains. The peak wind gust at Beaver, Oklahoma was 46 mph; south of the fire, surface winds were gusting to 43 mph at Perryton (in far the northern Texas Panhandle), and west of the fire winds gusted to 42 mph at Guymon (in the Oklahoma Panhandle). A large-scale animation of 1-minute GOES-16 Visible images from the AOS site (below) indicated that the smoke plume was transported northeastward across Kansas and eventually moved over south-central Nebraska. Smoke reduced the surface visibility to 6 miles at Dodge City as it moved across southwestern Kansas.

GOES-16

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

Shortwave Infrared images from MODIS (3.7 µm) and VIIRS (3.74 µm) (below) displayed three snapshots of the 10-15 mile long thermal anomaly (elongated cluster of black pixels) associated with the wildfire.

Shortwave Infrared images from MODIS (3.7 µm) and VIIRS (3.74 µm) [click to enlarge]

Shortwave Infrared images from MODIS (3.7 µm) and VIIRS (3.74 µm) [click to enlarge]

===== 08 March Update =====

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images at 0857 UTC [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images at 0857 UTC [click to enlarge]

During the subsequent overnight hours, a comparison of NOAA-20 VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images at 0857 UTC or 3:57 am local time (above) revealed the dark southwest-to-northeast oriented burn scar, with isolated small fires still burning along the northwestern periphery of the burn scar. Note: the NOAA-20 images are incorrectly labelled as Suomi NPP.

===== 09 March Update =====

GOES-16 Land Surface Temperature product and

GOES-16 Land Surface Temperature product and “Red” Visible (0.64 µm) image [click to enlarge]

A toggle between a GOES-16 Land Surface Temperature product and the corresponding Visible image (above) showed the fire burn scar at 2101 UTC on 09 March. Land Surface Temperature values were 10ºF warmer within the burn scar (middle 80s F, shades of yellow to orange) compared to areas immediately adjacent to the burn feature.