NtMicro RGB: Fog vs Stratus

A veritable buffet of things to digest are occurring in this Nighttime Microphysics RGB animation from 0600 to 1000 UTC in the early morning of 3/28/17 where multi-state impacts of stratus and fog are seen (Fig 1). In blue/aqua to gray shades, the low cloud features are developing over the central CONUS while being sandwiched between Spring-time cyclones in the East and West.  The massive spreading of the stratus and fog can’t be missed and numerous METAR observations across the central CONUS verified the aviation hazards.

loopNtMicro-2017328_06to09Z

Figure 1. Nighttime Microphysics RGB from GOES-16 at 0602 to 0957 UTC on 28 March 2017 over the U.S.

For the above and subsequent images/animations: NOAA’s GOES-16 satellite has not been declared operational and its data are preliminary and undergoing testing. Users receiving these data through any dissemination means  (including, but not limited to, PDA and GRB) assume all risk related to their use of GOES-16 data and NOAA disclaims any and all warranties, whether express or implied, including (without limitation) any implied warranties of merchantability or fitness for a particular purpose.

Focusing on the Tennessee and Lower Mississippi Valley regions, the fast motion of the animation from 0900 to 1130 UTC allows one to see the development of fog while other stratus clouds  pass to the east/northeast (Fig 2.).  Note that fog develops in the various low-lying areas, particularly eastern Tennessee valleys.  There is also a separate push of fog, noted by the black dotted oval of Figure 3, that moves southward along the back side of the eastern cyclone.  The METAR stations in the oval show the lowest visibility observations occurring in this area of southern and western Tennessee as well as northern Alabama.  A bit further upstream (north) from the push of fog there is a layer of very low stratus also moving southward and causing MFVR to IFR conditions.  With the large amount of precipitation from the previous day and relatively light winds overnight, a variety of fog and stratus developed over a wide area as the cyclone passed.  While not extremely common there are instances where fog develops even with  low stratus present overhead.  One can see this in central Missouri where fog is reported but the RGB shows stratus with large water droplets at their tops.  Fog below stratus was experienced at times in northern Alabama as well.

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Figure 2. Nighttime Microphysics RGB from GOES-16 at 0902 to 1122 UTC on 28 March 2017 centered over western Tennessee and covering the Tennessee and Upper Mississippi Valleys.

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Figure 3. METAR station plot from the Aviation Weather Center ADDS site (left) and the Nighttime Microphysics RGB.  Both from near 1100 UTC with annotations of fog and stratus locations and movement.  Blue arrow in METAR shows direction of movement and shared black dotted oval notes locations of lowest visibility reports.

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