Mesoscale convective system over the Northern Plains

June 5th, 2018 |

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images, with plots of SPC storm reports [click to play MP4 animation]

GOES-16 (GOES-East) “Clean” Infrared Window (10.3 µm) images (above) showed showed the development of thunderstorms over the northern Plains late in the evening on 05 June 2018 — these storm clusters exhibited upscale growth and merged into a large Mesoscale Convective System (MCS) over North Dakota and South Dakota during the overnight hours. SPC storm reports are plotted on the images, parallax-corrected to be at a location corresponding to cloud-top features at a mean elevation of 10 km; notable reports included wind gusts of 100 mph in South Dakota, 71 mph in North Dakota, and 67 mph in Minnesota.

A 1-km resolution Terra MODIS Infrared Window (11.0 µm) is shown below, with with plots of SPC storm reports that occurred within +/- 1 hour of the image. The coldest storm-top infrared brightness temperatures on the image were -77ºC in eastern North Dakota and central South Dakota.

Terra MODIS Infrared Window (11.0 µm) image, with SPC storm reports [click to enlarge]

Terra MODIS Infrared Window (11.0 µm) image, with SPC storm reports [click to enlarge]

PyroCumulonimbus cloud in Texas

May 11th, 2018 |

GOES-16

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

A large pyroCumulonimbus (pyroCb) cloud developed from the Mallard Fire in the Texas Panhandle on 11 May 2018, aided by warm temperatures and strong winds ahead of an approaching dryline (surface analyses).  1-minute Mesoscale Domain Sector 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 large thermal anomaly or “hot spot” (red 3.9 µm pixels) and the rapid development of  the pyroCb cloud beginning shortly after 1900 UTC. Cloud-top infrared brightness temperatures cooled to -60 ºC — the tropopause temperature on the 00 UTC Amarillo sounding — by around 2130 UTC. On the Shortwave Infrared imagery, note the relatively warm (darker gray) appearance of the pyroCb cloud top — a characteristic signature of pyroCb anvils due to enhanced reflection of solar radiation off of smaller cloud-top particles.

4-panel comparisons of Suomi NPP VIIRS Visible (0.64 µm), Near-Infrared “Snow/Ice” (1.61 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images at 1936 UTC and 2029 UTC (below) revealed that the maximum differences between 3.74 µm and 11.45 µm cloud-top infrared brightness temperatures — at the same location on the pyroCb anvil — were 86ºC (+26ºC and -59ºC at 1936 UTC) and 91.5ºC (+27.5ºC and -63ºC at 2029 UTC).

Suomi NPP VIIRS Visible (0.64 µm), Near-Infrared

Suomi NPP VIIRS Visible (0.64 µm, upper left), Near-Infrared “Snow/Ice” (1.61 µm, upper right), Shortwave Infrared (3.74 µm, lower left) and Infrared Window (11.45 µm, lower right) images at 1936 UTC and 2029 UTC [click to enlarge]

Lightning was detected from portions of the smoke plume, as well as the core of the pyroCb thunderstorm.

After dark, the thermal signature of the Mallard Fire was also apparent on GOES-16 Near-Infrared “Cloud particle size” (2.24 µm) imagery (below).

GOES-16 Near-Infrared

GOES-16 Near-Infrared “Cloud particle size” (2.24 µm, top), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.3 µm, bottom) images, with hourly plots of surface reports [click to play MP4 animation]

===== 12 May Update =====

Terra MODIS True-color and False-color images [click to enlarge]

Terra MODIS True-color and False-color images [click to enlarge]

In a comparison of 250-meter resolution Terra MODIS True-color and False-color Red-Green-Blue (RGB) images from the MODIS Today site (above), the Mallard Fire burn scar was evident in the False-color. Both images showed a smoke plume from ongoing fire activity, which was drifting northward across the Texas Panhandle.

The corresponding Terra MODIS Land Surface Temperature product (below) indicated that LST values within the burn scar were as high as 137ºF (darker red enhancement), in contrast to values around 100ºF adjacent to the burn scar.

Terra MODIS Land Surface Temperature product [click to enlarge]

Terra MODIS Land Surface Temperature product [click to enlarge]

Valley fog and mountain snow in the Catskills of New York

May 1st, 2018 |

As pointed out by NWS Binghamton, valley fog and higher-elevation snow cover was apparent on GOES-16 (GOES-East) Visible imagery in the Catskills of southeastern New York on the morning of 01 May 2018. A closer view comparing GOES-16 “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (below) showed the dissipation of the valley fog, followed by the melting of the snow cover in higher terrain (snowfall amounts of up to 3-4 inches fell in the area on 29 April). The Snow/Ice imagery was helpful in discriminating between the brighter valley fog features and the darker snow cover.

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and Near-Infrared “Snow/Ice” (1.61 µm, right) images, with hourly plots of surface reports [click to play animation | MP4]

A 250-meter resolution Terra MODIS True-color Red-Green-Blue (RGB) image acquired from the SSEC Direct Broadcast ground station (below) showed the remaining snow cover over the Catskills (near the center of the image) at 1539 UTC.

Terra MODIS True-color image [click to enlarge]

Terra MODIS True-color image [click to enlarge]

Wildfires in northeastern Oklahoma

March 24th, 2018 |

GOES-16

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

GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) showed smoke plumes and fire “hot spots” associated with numerous wildfires burning in northeastern Oklahoma on 24 March 2018.

A comparison of Terra/Aqua MODIS and Suomi NPP VIIRS Shortwave Infrared images (below) showed  higher-resolution view of the fire hot spots.

Terra/Aqua MODIS and Suomi NPP VIIRS Shortwave Infrared images with surface observations plotted in cyan [click to enlarge]

Terra/Aqua MODIS and Suomi NPP VIIRS Shortwave Infrared images with surface observations plotted in cyan [click to enlarge]