MODIS-VIIRS Night-time Microphysics RGB and 11-3.9um Imagery to Distinguish Cloud Heights

A semi-permanent large scale trough and its associated cold temperatures have  plagued much of the western US since Friday, January 11th.  Shortwave troughs embedded within the large scale feature periodically rotated in and out of New Mexico sending the occasional back door front into the eastern plains.  One such front slid southward on Saturday, January 12th before stalling just shy of Roswell.  Later that night, low clouds formed behind the front across much of the area.  Per area observations, no fog was reported at the time of the images below.

Another shortwave trough was approaching New Mexico from the north. The MODIS-VIIRS Night-time Microphysics RGB satellite image (left) clearly showed the difference between low-level clouds associated with the back door front (lime green) and the mid-level clouds associated with the approaching shortwave (brownish).  Interestingly, the imagery also captured low clouds present over the Zuni Mountains, an area void of surface observations, but did not show low clouds over any of the adjacent high terrain.  Low clouds nestled up against the west slopes of the northern mountains also showed up quite well.

To further distinguish the low clouds from the mid level clouds, the MODIS-VIIRS 11-3.9um imagery was used in conjunction with the aforementioned image.  In the 11-3.9um imagery, the low clouds clearly stand out in bright yellow, though in northwest New Mexico, there is very little, if any, indication of cloud cover.


Graphicast showing how night-time cloud cover was depicted on the MODIS-VIIRS Night-time Microphysics RGB and 11-3.9um imagery.

For reference, cloud ceilings per area observations across the eastern plains ranged from 1500 to 3500 feet, while ceilings across northwest NM were approximately 8000 feet.

The graphicast above was posted to NWS Albuquerque’s webpage and facebook page early Sunday morning, January 13th.

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