* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

As cold arctic air continued to move eastward across North Dakota on 07 November 2017, GOES-16 “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (above) showed “lake effect” cloud plumes streaming east-northeastward from Lake Sakakawea (and also from Missouri River). The Snow/Ice images were the most useful for discriminating between supercooled water droplet cloud plumes (brighter shades of white) and the surrounding snow-covered land surfaces (darker shades of gray).

During the preceding nighttime hours, Suomi NPP VIIRS and Aqua MODIS Infrared Brightness Temperature Difference images (below) — the legacy “fog/stratus product” — revealed that the orientation of the Lake Sakakawea cloud plume changed as surface winds switched from northwesterly to westerly.

The Aqua MODIS Sea Surface Temperature product (below) indicated that the water in Lake Sakakawea was as warm as 47.9ºF (darker green enhancement) — significantly warmer than the surface air passing over it, which was generally in the 5 to 15ºF range.

The large cloud plume from Lake Sakakawea was also very evident on GOES-16 Day Snow-Fog Red-Green-Blue (RGB) images (below). Farther to the east, smaller and shorter-lived cloud plumes could also be seen originating from Devils Lake (along the Benson/Ramsey county line) and Stump Lake (in Nelson county).

Taking a closer look at the Lake Sakakawea area, the brighter signature of steam plumes rising from power plants located south and southeast of the lake (2 in Mercer county, and 1 in McLean county) could be spotted on the Day Snow-Fog RGB images (below).

Due to the low sun angle and the snow-covered land surface, morning shadows from these rising steam plumes could be seen on GOES-16 “Red” Visible (0.64 µm) images (below).

Special thanks to Carl Jones (NWS Grand Forks) for bringing this case to our attention, and supplying the AWIPS RGB and Visible images at the bottom of the blog post.

 

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* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

An outbreak of severe weather occurred across the Midwestern US on 05 November 2017, with a number of tornadoes (including a 39-mile long track EF-2 tornado) in Indiana and Ohio. A GOES-16 Mesoscale Sector provided imagery at 1-minute intervals during this event — “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) with plots of SPC storm reports (T=tornado; W=damaging winds; H=hail) showed the development and motion of the severe thunderstorms. The locations of the plotted SPC storm reports have been parallax-corrected upward from the surface, to match a mean storm-top height of 10 km.

A toggle between Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images (below) showed a snapshot of the storm at 1803 UTC. SPC storm reports within about  +/- 30 minutes of the image time are also plotted. The coldest storm-top infrared brightness temperatures were -71ºC (black enhancement), over southern and eastern Indiana. The VIIRS instrument will also fly on the JPSS series of satellites.

One interesting aspect seen on 1806 UTC Aqua MODIS Water Vapor (6.7 µm) imagery (below) was the signature of strong subsidence (darker blue enhancement) immediately upwind — along the western edge — of the 2 larger areas of severe convection. Once again, SPC storm reports within about +/- 30 minutes of the image time are plotted.

Additional information on this event can be found on the Satellite Liaison Blog, as well as the NWS forecast offices at Indianapolis IN, Northern IN, and Wilmington OH.

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* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

As arctic air began to spread eastward across Montana — where the coldest temperature in the US was -12ºF — behind an inverted trough (surface analyses) on 04 November 2017, GOES-16 “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (above) revealed bands of “lake effect” (from Fort Peck Lake) and “river effect” (slightly upstream, from the Missouri River) clouds. On the Snow/Ice images, sow cover (and cold ice crystal clouds) appear as darker shades of gray, in contrast to supercooled water droplet clouds which are brighter white. Note that surface air temperatures at Glasgow (KGGW) and Jordan (KJDN) were generally in the 15 to 20ºF range.

A 1-km resolution Aqua (overpass times) MODIS Sea Surface Temperature product (below) indicated that SST values were still 50ºF and warmer (darker shades of green) in parts of Fort Peck Lake. Farther to the west, a deeper portion of the Missouri River exhibited SST values in the mid-40s F (cyan) — this area  was likely the source of the river-effect cloud features. The temperature difference between the surface air and the warmer lake/river water was therefore in the 30-35ºF range.

In a toggle between 250-meter resolution Terra (overpass times) MODIS true-color (Bands 1/4/3) and false-color (Bands 7/2/1)  Red-Green-Blue (RGB) images from the MODIS Today site (below), the false-color image helps to highlight the bands of supercooled water droplet river effect and lake effect clouds (brighter white) — snow cover (and high-altitude ice crystal clouds) appear as shades of cyan.

A 30-meter resolution Lnndsat-8 false-color image (below) captured the dissipating remnants of the Missouri River cloud plume at 1800 UTC; a few cumulus cloud streets could also be seen over Fort Peck Lake, along the far eastern edge of the image swath.

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GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing

Red-Green-Blue (RGB) Composite Images are a handy way of showing information from multiple satellite bands (or band differences) at once. The image above shows an RGB created by NOAA Scientist Andy Heidinger that uses the GOES-16 Visible Band (0.64 µm) as the green component, Snow-Ice Band (1.61 µm) as the blue component and Cirrus Band (1.38 µm) as the red component to tease out information about Cloud Type.  The Cirrus Channel (unique to GOES-16 as far as Geostationary Satellites are concerned) is a handy channel to use in an RGB because it discriminates very well between high clouds and low clouds.  In a moist environment, low clouds are not apparent at all in the Cirrus Band.  The toggle below shows the Visible, Snow/Ice and Cirrus Channels at 1502 UTC.  Low clouds over Kansas have no signal in the Cirrus channel — there are other differences as well, of course.

In the RGB, Thin cirrus clouds (for example, the contrails over Illinois) are red, opaque ice clouds (over the western Atlantic) are yellow (having a contribution from both Red and Green Components), Low Clouds (over the southern Plains) are Cyan (having a contribution from Blue and Green), snow is Green, and lofted water clouds are white (having a contribution from all three). As the atmosphere dries, the amount of lofting necessary for the Cirrus channel to view a cloud composed of water droplets (and therefore white in the RGB) decreases.

The Day Land Cloud RGB (sometimes called ‘Natural Color’) can also be used to estimate cloud type. The toggle below shows how the Cloud Type RGB has more gradations between ice cloud type because of the use of the Cirrus Channel.  The Cloud Type RGB also highlights the contrails and thin cirrus more effectively, again because of the use of the Cirrus Channel

 

Three toggles below show the Snow/Ice and Visible and Cirrus channels zoomed in over Illinois (where contrails are present), over the western Atlantic (where strong convection is occurring) and over the southwestern United States.

GOES-16 also has a Baseline Product that shows Cloud Type. That is shown below. The 1502 UTC Image was incomplete, so the 1507 UTC image is shown.

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