Two similarly-sized cyclones over the western Atlantic Ocean have very different representations in the Air Mass RGB product. Tropical Cyclone Chris is mostly white surrounded by green. The ‘Red’ component of the Air Mass RGB is the Split Water Vapor Difference Product, and when that value is small, a large red component is present. In tropical airmasses with abundant moisture, the 6.2 µm and 7.3 µm water vapor infrared brightness temperatures are similar. The different colors in the extratropical cyclone to the northeast of Chris arise because of subsiding dry air that affects all three components of the Air Mass RGB product.

One way to help interpret the RGB product is to load all three component parts, as shown below. The Split Water Vapor Difference (Red Component of the Air Mass RGB, upper right), the Split Ozone Difference (Green Component of the RGB, lower left) and the Upper Level Water Vapor (6.19 µm, Blue Component of the RGB, lower right). These are shown in 2037 UTC in the default enhancement, and then color-coded Red, Green, Blue using the Brightness Temperature limits in the RGB definition.

Added: The Band 13 image (Clean Infrared Window, 10.3 µm) for 2037 UTC is shown below.

Thanks to Paul Ford, ECC Canada, for alerting us to this very interesting juxtaposition!

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The mesoscale convective vortex (thunderstorm complex) from Arizona overnight is evident a small eye on visible satellite and large mass of debris clouds over #socal in addition to the morning dust layer in the Coachella Valley #cawx #Monsoon2018 pic.twitter.com/VE3QB6iKfh

— NWS San Diego (@NWSSanDiego) July 9, 2018

As mentioned by NWS San Diego, monsoon thunderstorms that developed over Arizona spawned a small Mesoscale Convective Vortex (MCV). The animation below shows nighttime GOES-16 (GOES-East) “Clean” Infrared Window (10.3 µm) images, followed by daytime GOES-16 “Red” Visible (0.64 µm) images — the center of the MCV circulation briefly exhibited an “eye-like” appearance just after 16 UTC (south of the California/Mexico border).

A 1-km resolution NOAA-19 Infrared Window (10.8 µm) image at 1132 UTC (below) showed a more detailed view of the small cluster of thunderstorms responsible for the MCV — the convection produced 0.68″ of rainfall near Yuma KNYZ in far southwestern Arizona, and generated an outflow boundary which produced wind gusts to 46 mph at Thermal, California KTRM (NWS statements).

A toggle between 1-km resolution NOAA-15 and NOAA-18 Visible (0.63 µm) images (below) revealed the emergence of the eye-like MCV center in far northern Baja California (just southeast of Campo, California KCZZ) at 1547 UTC.

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A toggle between Terra MODIS True Color Red-Green-Blue (RGB) images (from the MODIS Today site) on 06 June, 05 July and 09 July 2018 (above) revealed the brightening yellow-green hues of blooming canola fields across parts of northeastern North Dakota and southern Manitoba. Note that changes can even be seen between the 2 days in early July!

Credit to NWS Grand Forks for alerting us to this interesting phenomenon.

Using @NOAASatellites' #GOES16 "true color" capability, we can see vast fields of blooming #canola within northern North Dakota into the Canadian southern prairie provinces shaded in speckled hues of yellow. ? #ndwx #mbwx #ndag #mbag pic.twitter.com/pOzBgDukY3

— NWS Grand Forks (@NWSGrandForks) July 10, 2018

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Tropical Depression Number 3 was upgraded to Tropical Storm Chris at 0900 UTC 8 July. Chris has been mostly stationary on 8 July. The visible animation, above, from Sunday 8 July shows excellent upper-level outflow to the northeast and southwest of the storm, and persistent convection over the center.  The Clean Window animation over the same time, below, shows a compact center with periodic overshooting tops.

The toggle below between 2212 UTC on 6 and 8 July shows the general increase in organization of Chris, with a slight northwestward motion over the two days. In addition, the front that was over the eastern United States on 6 July is out over the Atlantic on 8 July, and Chris is embedded within the southwestern tail of the front.

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