1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Clean” Infrared Window (10.35 µm) images — with and without an overlay of GLM Flash Extent Density — and “Red” Visible (0.64 µm) images (above) showed showed Hurricane Delta as it intensified from a Category 2 to a Category 3 storm over the Gulf of Mexico during the daytime hours on 08 October 2020. Cloud-top infrared brightness temperatures of -90ºC and colder  (yellow pixels embedded within the darker shades of purple) were occasionally seen within the eyewall region of Delta, along with intermittent bursts of lightning activity.

A toggle between Suomi NPP VIIRS Infrared Window (11.45 µm) and Visible (0.64 µm) images of Hurricane Delta shortly before it intensified to a Category 3 storm are shown below; the coldest cloud-top infrared brightness temperature at that time was -93.0ºC.

In a time-matched comparison of Infrared images from Suomi NPP and GOES-16 (below), the coldest cloud-top infrared brightness temperature sensed by GOES-16 was 5.6ºC warmer (-87.4ºC); note the small northwestward parallax displacement that is inherent with GOES-16 imagery over the Gulf of Mexico. The same color enhancement is applied to both images.

===== 09 October Update =====

In a toggle between Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images at 0734 UTC or 2:34 am CDT on 09 October (above), the coldest cloud-top infrared brightness temperature was -93.8ºC (just northwest of the storm center).

1-minute GOES-16 Infrared and Visible images (below) showed Category 2 Hurricane Delta making landfall in southwestern Louisiana at 2300 UTC, producing wind gusts as high as 100 mph at Texas Point, Texas.

The MIMIC Total Precipitable Water product (below) indicated that Hurricane Delta was transporting a large amount of moisture northward across the Gulf of Mexico — rainfall totals included 15.64 inches at Evangeline Gardner, Louisiana.

The MIMIC-TC product (below) showed the deterioration of the eye and eyewall structure as Delta approached the Gulf Coast.

===== 10 October Update =====

A before (04 October) / after (10 October) comparison of Suomi NPP VIIRS True Color RGB images from the VIIRS Today site (above) revealed a marked increase of turbidity within the more shallow shelf waters of Texas and Louisiana, due to extensive mixing from the wind field associated with Delta. A comparison of VIIRS False Color images from those 2 days (below) highlighted inland areas with significant flooding that resulted from heavy rainfall and/or storm surge (darker shades of blue).

A GOES-16 River Flood Detection product viewed using RealEarth (below) helped to quantify the severity of flooding resulting from the landfall of Delta.

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1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Clean” Infrared Window (10.35 µm) images — with and without an overlay of GLM Flash Extent Density — and “Red” Visible (0.64 µm) images (above) showed showed an impressive convective burst near the center of Tropical Storm Delta, which developed a couple of hours before the storm reached Category 1 Hurricane intensity at 0000 UTC on 06 October over the Caribbean Sea. There was no GLM-detected lightning activity near the center of Delta during this 2100-0100 UTC time period.

A toggle between GOES-16 Infrared and Visible images at 2156 UTC (below) revealed a small tropical overshooting top near the center of the developing convective burst — which exhibited a cloud-top infrared brightness temperature as cold as -93.2ºC (yellow pixels embedded within the darker shades of purple).

===== 06 October Update =====

Hurricane Delta rapidly intensified to a Category 4 storm at 1520 UTC on 06 October — with 1-minute GOES-16 Infrared and Visible images (above) showing evidence of a more organized eye and eyewall structure, including a notable amount of lightning activity near the core of the storm.

GOES-16 Infrared Window (11.2 µm) images from the CIMSS Tropical Cyclones site (below) indicated that Delta was moving through an environment of low deep-layer wind shear as the hurricane was moving over water possessing very high ocean heat content.

===== 07 October Update =====

A comparison Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images (above) revealed a small area with cloud-top infrared brightness temperatures as cold as -100.9ºC (within the small cluster of red pixels) just east of the island of Cozumel, Mexico. Even though Delta was still moving over water possessing very high ocean heat content, its intensity was reduced from Category 4 to Category 3 around this time.

A time-matched comparison of Infrared images from Suomi NPP and GOES-16 is shown below; a cloud-top infrared brightness temperature of -95.8ºC was sensed by GOES-16. There was significant parallax associated with the Suomi NPP image, since Hurricane Delta was located along the far western edge of the descending overpass swath. The same color enhancement is applied to both images.

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1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed Category 4 Hurricane Marie over the East Pacific Ocean on 02 October 2020. Although there was frequently some high cloud debris covering the eye, hints of low-altitude mesosvortices within the eye could be seen at times. The coldest cloud-top infrared brightness temperatures were in the -85 to -88ºC range.

GOES-17 Infrared Window (11.2 µm) images from the CIMSS Tropical Cyclones site (below) indicated that Marie was moving through an environment of relatively low deep-layer wind shear.

===== 03 October Update =====

A toggle between time-matched Infrared Window images of the eye and eyewall region of Hurricane Marie from Suomi NPP (SNPP) and GOES-17 (below) highlighted the differences in spatial resolution — 375-m with SNPP VIIRS, vs 2-km (at satellite sub-point) with GOES-17 ABI — and the parallax displacement inherent with GOES-17 imagery at that location (approximately 9 km to the northeast). The coldest cloud-top infrared brightness temperature was -85.4ºC on the SNPP image, compared to -81.8ºC on the GOES-17 image; small-scale features such as the gravity waves propagating radially outward from the eye were seen in the higher resolution SNPP image. Note: the 0929 UTC time stamp on the SNPP image was the time that the ground station antenna began receiving the descending overpass signal – the satellite actually passed over Marie’s location at 0943 UTC.

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GOES-16 (GOES-East) True Color Red-Green-Blue (RGB) images created using Geo2Grid (above) showed plumes of smoke drifting across parts of Colorado on 30 September 2020. The most smoke prominent plume originated from the Mullen Fire in far southern Wyoming — which produced a pyroCb cloud on 19 September.

On the following morning, the hazy signature of low-altitude smoke that had settled overnight into the North Park and Middle Park plateau areas of north-central Colorado was evident in CIMSS Natural Color RGB images (below). During the morning hours, this smoke restricted the surface visibility to 1-3/4 mile at Walden and 5 miles at Kremmling, before gradually beginning to disperse in the afternoon hours.

The signature of North Park and Middle Park plateau smoke was more vivid using GOES-16 True Color imagery which includes a correction for Rayleigh scattering (below).

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