The Air Mass RGB views two different cyclones

July 9th, 2018 |

GOES-16 Air Mass RGB, 1542 – 2042 UTC on 9 July 2018 (Click to animate)

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.

Air Mass RGB (Upper Left), Split Water Vapor Difference (Upper Right), Split Ozone Brightness Temperature Difference (Lower Left) and 6.19 Upper-level Water Vapor Imagery (Lower Right) at 2037 UTC on 9 July (Click to enlarge)

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

GOES-16 “Clean Window” Infrared Image (10.3 µm), 2037 UTC on 9 July 2018 (Click to enlarge)

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

Mesoscale Convective Vortex generated by monsoon thunderstorms in Arizona

July 9th, 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).

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) and “Red” Visible (0.64 µm) images, with hourly plots of surface reports [click to play MP4 animation]

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).

NOAA-19 AVHRR Infrared Window (10.8 µm) image [click to enlarge]

NOAA-19 AVHRR Infrared Window (10.8 µm) image [click to enlarge]

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.

NOAA-15 and NOAA-18 Visible (0.63 µm) images [click to enlarge]

NOAA-15 and NOAA-18 Visible (0.63 µm) images [click to enlarge]

Blooming canola fields in North Dakota and Manitoba

July 9th, 2018 |

Terra MODIS True Color RGB images on 06 June, 05 July and 09 July 2018 [click to enlarge]

Terra MODIS True Color RGB images on 06 June, 05 July and 09 July 2018 [click to enlarge]

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.