GOES-16 (GOES-East) Day Snow-Fog RGB and Day Cloud Phase Distinction RGB images (above) showed numerous industrial plumes — likely from power plants — streaming southward over parts of Texas on 24 February 2022. Particles emitted from power plant stacks acted to “seed” the surrounding supercooled water cloud droplets, creating a higher concentration of smaller cloud droplets — which were more efficient reflectors of incoming solar radiation, making the plumes appear brighter. Farther to the east, the tightly-spaced cloud bands of an undular bore were also apparent (1901 UTC image).

A higher-resolution view of these features was provided by a sequence of NOAA-20 VIIRS True Color RGB, False Color RGB, Visible and Near-Infrared images (below).

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Total Precipitable Water is a Level 2 Derived Product created from ABI (and ancillary) data (link to information on this product) The image above shows the product at 1900 UTC on 24 February 2022. It is immediately apparent that cloudy regions have no data! There are ways to fill in those gaps at different times of day.

NUCAPS thermodynamic profiles in AWIPS are derived from data from the CrIS (Cross-track Infrared Sounder) and ATMS (Advanced Technology Microwave Sounder) instruments on board NOAA-20. That thermodynamic data can be used to create fields of Total Precipitable Water, as shown below. Of course, the NUCAPS swath is limited geographically to the width of the CrIS and ATMS swaths, but values are created in clear and cloudy regions. Note that in AWIPS (which display system was used to create the imagery in this blog post) the gridded NUCAPS field has a different default color enhancement than what is shown below; create an AWIPS Procedure to load and enhance the swath with the same GOES-R enhancement used as a default in the image above.

If you combine both the GOES-R TPW estimates with NUCAPS estimates at the same time, you will get enhanced coverage in regions where interesting weather might be happening (near gradients in TPW, for example) beneath cloud cover. NOAA-20 NUCAPS swaths occur every 90 minutes in the afternoon. moving east to west across the CONUS. Thus, at 1730 UTC, a NUCAPS TPW swath was available over the eastern part of the United States, and it could be combined with GOES-R values at that time, as shown at bottom. At 2030 UTC, a swath along the west coast (not showed) occurred. A similar set of swaths will occur east-to-west between about 0530 UTC and 1000 UTC in the morning.

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AWIPS users can create a procedure to load gridded TPW fields in conjunction with GOES-R TPW fields, and use them as needed. AWIPS imagery in this blog post was created using the NOAA/NESDIS TOWR-S AWIPS Cloud Instance.

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VIIRS True-Color (above) and False-Color (below) imagery (available as an LDM pull from CIMSS) over the western Great Lakes at 1753 UTC (NOAA-20), 1844 UTC (Suomi-NPP) and 1937 UTC (NOAA-20, again) show the recent expansion of late-winter snowcover into southern Wisconsin and northern Iowa. Additionally, ice over the lake (more easily differentiated from clouds in False-Color imagery because the use of the 2.25 µm band in the ‘red’ component of that RGB means that ice/snow acquire a cyan or blue coloring, whereas non-glaciated clouds are white) is apparent, especially near the shoreline.

True Color imagery exploits the presence of the 0.55 µm band (A true ‘green’ band) on VIIRS. Thus, relationships between red, blue and ‘veggie’ bands are not needed for the creation of a simulated green band to make a true color imagery.

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VIIRS True- and False-color imagery is also available at the VIIRS Today website.

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VIIRS True Color and False Color RGB images from Suomi-NPP and NOAA-20 (above) revealed narrow swaths of lake effect snow cover — which appeared as shades of cyan in the False Color images — downwind of Milford Lake (located NW of Junction City) and Turtle Creek Lake (located NNW of Manhattan) in northeastern Kansas on 22 February 2022.

A sequence of Tulsa radar 0.5-degree base reflectivity images at 30-minute intervals (from 0700-1800 UTC) showed the lake effect bands streaming southeastward from those 2 lakes — followed by a toggle between Suomi-NPP VIIRS True Color and False Color RGB images at 1903 UTC (below). A northwesterly flow of cold arctic air (in the teens to single digits F) across the still-unfrozen water of the lakes picked up enough moisture to create narrow cloud bands that produced the accumulating snowfall.

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