One key advantage of the Nighttime Microphysics RGB is its ability to depict low-level cloud layers at night. These are marked by elevated red and green contributions within the RGB recipe, however a case from 6 April 2022 shows that not all low-level clouds look the same. Overnight a cold front was advancing southeastward through the central United States. Behind the cold front (Oklahoma, Kansas, Missouri, and Arkansas) we see that the stratus clouds are colored green-yellow, however, the stratus clouds ahead of the cold front (Texas, Louisiana, Mississippi, and Alabama) are light blue. The question is why?
While stratus clouds often have strong contributions from the red and green bands (indicating thick, water clouds), the relative bluecontribution from the Channel 13 Clean-IR Brightness Temperature (10.3 um) can highlight the relative temperature differences of stratus clouds. See the abbreviated RGB recipe for the Nighttime Microphysics RGB below.
To see this effect for yourself, you can compare the Nighttime Microphysics RGB to the Clean-IR Brightness Temperature imagery using the slider tool below. Note the position of the cold front (via the surface observations), where the colors of the stratus clouds change in the Nighttime Microphysics RGB, and the higher/lower Clean-IR Brightness Temperatures ahead/behind the cold front.
During the early morning hours of 14 March 2022, a plume of moisture from the Gulf of Mexico was advected northward prior to a severe weather setup later that day. Along with surface observations and RAP surface analysis data, imagery from the GOES-16 Nighttime Microphysics RGB provided conformation of this moisture advection with stratus clouds developing across eastern Texas and southern Oklahoma (green-yellow) from Figure 1. Strong contributions in the red and green bands signify thick clouds that mostly contain water, helping to determine that these are low level stratus clouds driven by the synoptic scale advection of low level moisture across the region.
The NWS Storm Prediction Center issued a Slight Risk for northeast Texas and the Ark-La-Tex region, with all hazards (tornadoes, large hail, and damaging winds) possible (see slideshow below). Use of the Nighttime Microphysics RGB in this scenario may provide conformation of the moisture advection, along with its current spatial extent in regions where few surface observations exist. Monitoring the extent of these stratus clouds also provides a ‘first look’ at which areas will receive more or less solar heating during the morning, which may impact the initiation time, coverage, and maximum strength of convection later in the day.