* GOES-17 images shown here are preliminary and non-operational *

A comparison of Visible images from GOES-15 (GOES-West), GOES-17 and GOES-16 (GOES-East) (above) showed an isolated thunderstorm that developed in the Nebraska Panhandle late in the day on 29 August 2018. The storm produced hail (SPC storm reports), and also exhibited an Above Anvil Cirrus Plume. The images are displayed in the native projection of each satellite, with no re-mapping.

One other feature that was seen north of the thunderstorm was smoke which was being transported eastward from the Britania Mountain Fire in southeastern Wyoming. The smoke was more apparent on the GOES-17 and GOES-16 images as forward scattering increased toward sunset.

Shortwave Infrared imagery from the 3 satellites revealed important differences affecting fire detection: namely spatial resolution and viewing angle. The 3.9 µm detector on the GOES-15 Imager has a spatial resolution of 4 km (at satellite sub-point), compared to 2 km for the GOES-16/17 ABI. Given that the fire was burning in rugged mountain terrain, the view angle from each satellite had an impact on the resulting bire brightness temperature values. For example, the first indication of very hot (red-enhanced) pixels was at 1527 UTC from GOES-16/17, vs 1715 UTC from GOES-15; at the end of the day, the very hot fire pixels were no longer seen with GOES-15 after 2300 UTC, but continued to show up in GOES-17 imagery until 0042 UTC and in GOES-16 imagery until 0122 UTC.

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GOES-17 images shown here are preliminary and non-operational

The presence of GOES-17 data means that 4 mesoscale sectors, each taking 1-minute imagery, are over the United States. In the example above, from 1616 UTC on 29 August 2018, there is no overlap. (Note: Three of the Four are in their default locations; the Mesoscale sector over the northeast United States has been shifted north to monitor convection over New England).

On 28 August 2018, however, two mesoscale sectors overlapped over the central United States, and sampled convection developing over Oklahoma (that subsequently caused wind damage in Roger Mills County in western Oklahoma). The Stereoscopic View of that convection is shown below. To view the convection in three dimensions, cross your eyes until you see 3 images, and focus on the image in the center. An animated gif (215 Megabytes!!) is available here.

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Thunderstorms produced a variety of severe weather (SPC storm reports) as they moved eastward across the Upper Midwest on 28 August 2018. 1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) and “Clean” Infrared Window (10.3 µm) images (below) showed the development and progression of the severe convection across central Wisconsin.

Toggles beween Visible and Infrared images from Terra MODIS (1715 UTC), Aqua MODIS (1855 UTC) and Suomi NPP VIIRS (1945 UTC) are shown below.

These storms also brought heavy rain, which resulted in flooding that closed Interstate 90/94 near Mauston (about halfway between Madison and Fort McCoy) — that area received about 10 inches of rainfall in a 48-hour period (below). Amtrack trains were also forced to stop overnight near that same area, due to flooded tracks.

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* GOES-17 images shown here are preliminary and non-operational *

Beginning at 1530 UTC on 28 August 2018, GOES-17 data and imagery became available via the GOES Rebroadcast (GRB) distribution mechanism — and beginning at 1700 UTC via the Satellite Broadcast Network (SBN) that provides data to AWIPS (above). While images are available from all 16 of the ABI spectral bands, it is important to note that ABI cooling system issues will affect the image quality from certain bands during certain times.

GOES-17 Mid-level Water Vapor (6.9 µm) imagery is shown below.

A closer look using1-minute Mesoscale Domain Sector GOES-17 “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (below) showed ship tracks in the Pacific Ocean off the coast of Washington, Oregon and northern California. The ship tracks appear warmer in the 3.9 µm imagery because aerosols from the exhaust of ships cause a “cloud seeding effect”, which results in a higher concentration of smaller cloud droplets compared to the surrounding unperturbed marine boundary layer clouds. These smaller cloud droplets are more effective reflectors of sunlight, resulting in a warmer appearance (darker orange to red enhancement) on Shortwave Infrared images.

GOES-17 is currently positioned over the Equator at 89.5º West longitude during its checkout phase, but will eventually be moved to 137º West and become the operational GOES-West satellite later in 2018. The current coverage as viewed in the operational GOES-West perspective is shown below — Hawai’i and far southeastern Alaska appear in the limb of the satellite view.

However, Full Disk images in AWIPS are not available at full resolution; to get the best view of Alaska, for example, one must use imagery processed by software such as McIDAS. On this particular day, the peaks of Denali and the Alaska Range extended above the low-level clouds, and could be seen on the extreme limb of GOES-17 “Red” Visible (0.64 µm) imagery (below).

GOES-16 (GOES-East) is positioned at 75.2º West longitude — the western extent of its coverage is shown below. Hawai’i and Alaska (with the exception of the Alaska Panhandle) are not scanned by GOES-16.

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