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.

View only this post Read Less

* 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.

View only this post Read Less

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

The GOES Rebroadcast (GRB) is now transmitting GOES-17 data that remain Preliminary and non-operational.  The first data sent were at 1530 UTC on 28 August. The toggle above shows Bands 3 (“Veggie Band”, 0.86 µm) and Band 7 (“Shortwave Infrared”, 3.9 µm) from the Meso-1 sector that was positioned over the West Coast at 1607 UTC on 28 August 2018.  Band 13 (“Clean Window”, 10.3 µm), below, from the Meso-2 sector is over the High Plains.

Visible (Band 2, 0.64 µm) Imagery from 1531 UTC, below, was produced using CSPP Geo, a software package that reads the GRB signal and produces imagery. (Image courtesy Graeme Martin, CIMSS)

The Geo2Grid Software Package can be used with GRB output to produce True-Color imagery, as shown below. The full-disk image was created in about 8 minutes using a centOS server, and it is corrected for atmospheric and solar zenith angle effects. Green Band information is simulated from other ABI channels.

Full Disk examples of imagery from all 16 ABI bands (in addition to a Natural Color RGB image) are shown below (courtesy Mat Gunshor, CIMSS).

View only this post Read Less

 * 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 a severe thunderstorm that developed ahead of an advancing cold front (surface analyses) in central South Dakota late in the day on 26 August 2018. This storm produced hail as large as 4.0 inches in diameter (SPC storm reports), and also exhibited an above anvil cirrus plume (AACP) which is a signature often associated with severe thunderstorms.

The images are displayed in the native projection of each satellite, with no re-mapping. Note the important differences due to satellite scan strategy — the GOES-15 imager was initially performing a Full Disk scan, so imagery was only available every 30 minutes; the GOES-17 ABI was scanning at the standard “CONUS Sector” 5 minute interval; a GOES-16 ABI Mesoscale Domain Sector was providing images every 1 minute.

View only this post Read Less