Transverse banding around a decaying MCS

June 14th, 2018 |

Aqua MODIS Visible (0.65 µm), Near-Infrared

Aqua MODIS Visible (0.65 µm), Near-Infrared “Cirrus” (1.37 µm), Water Vapor (6.7 µm) and Infrared Window (11.0 µm) images, with pilot reports of turbulence plotted in cyan [click to enlarge]

A comparison of Aqua MODIS Visible (0.65 µm), Near-Infrared “Cirrus” (1.37 µm), Water Vapor (6.7 µm) and Infrared Window (11.0 µm) images (above) showed widespread transverse banding along the northern and eastern periphery of a decaying Mesoscale Convective System (MCS) that was moving from Iowa into Illinois and Missouri on 14 June 2018.

GOES-16 (GOES-East) Near-Infrared “Cirrus” (1.37 µm), Mid-level Water Vapor (6.9 µm) and “Clean” Infrared Window (10.3 µm) images with pilot reports of turbulence are shown below.

GOES-16 Near-Infrared

GOES-16 Near-Infrared “Cirrus” (1.37 µm) images, with hourly plots of turbulence [click to play MP4 animation]

GOES-16 Mid-level Water Vapor (6.9 µm) images, with hourly plots of turbulence [click to play MP4 animation]

GOES-16 Mid-level Water Vapor (6.9 µm) images, with hourly plots of turbulence [click to play MP4 animation]

GOES-16 "Clean" Infrared Window (10.3 µm) images, with hourly plots of turbulence [click to play MP4 animation]

GOES-16 “Clean” Infrared Window (10.3 µm) images, with hourly plots of turbulence [click to play MP4 animation]

 

Turbulence associated with transverse banding

June 2nd, 2018 |

GOES-16 (GOES-East) Near-Infrared “Cirrus” (1.37 µm), Mid-level Water Vapor (6.9 µm) and Upper-level Water Vapor (6.2 µm) images (below) showed the evolution of this transverse banding — a cloud signature often associated with turbulence — early in the day on 02 June 2018.

GOES-16 Near-Infrared

GOES-16 Near-Infrared “Cirrus” (1.37 µm, left), Mid-level Water Vapor (6.9 µm, center) and Upper-level Water Vapor (6.2 µm, right) images, with hourly pilot reports of turbulence [click to play MP4 animation]

A toggle between 1-km resolution Aqua MODIS Water Vapor (6.7 µm) and Cirrus (1.37 µm) images at 1842 UTC is shown below; the transverse banding was beginning to dissipate around that time.

Aqua MODIS Water Vapor (6.7 µm) and Cirrus (1.37 µm) images, with pilot reports of turbulence [click to enlarge]

Aqua MODIS Water Vapor (6.7 µm) and Cirrus (1.37 µm) images, with pilot reports of turbulence [click to enlarge]

Transverse banding: a signature of potential turbulence

July 20th, 2016 |

GOES-13 Infrared Window (10.7 um) images, pilot reports of turbulence, Turbulence AIRMET boundaries [click to play animation]

GOES-13 Infrared Window (10.7 um) images, pilot reports of turbulence, Turbulence AIRMET boundaries [click to play animation]

GOES-13 (GOES-East) Infrared Window (10.7 µm) images (above) showed the formation of tendrils of transverse banding along the northern semicircle of  decaying mesoscale convective systems as they moved eastward across Nebraska and Iowa on 19 July 2016. Pilot reports of turbulence are plotted on the images, along with Turbulence AIRMET polygons issued at 0800 UTC and 1400 UTC. Most of the pilot reports of turbulence were in the Light to Moderate category, although there was one report of Moderate to Severe intensity at 1612 UTC over eastern Iowa.

The corresponding GOES-13 Water Vapor (6.5 µm) images (below) perhaps highlighted the transverse banding features a bit better at times, since the weighting function for that spectral band generally peaks in the middle to upper troposphere where the transverse banding cloud features existed.

GOES-13 Water Vapor (6.5 um) images, pilot reports of turbulence, Turbulence AIRMET boundaries [click to play animation]

GOES-13 Water Vapor (6.5 um) images, pilot reports of turbulence, Turbulence AIRMET boundaries [click to play animation]

A sequence of Infrared Window images from POES AVHRR (10.8 µm) and Suomi NPP VIIRS (11.45 µm) (below) showed a higher-resolution view of the initial formation of transverse banding during the 0411 to 1008 UTC time period.

Infrared Window images from POES AVHRR (10.8 µm) and Suomi NPP VIIRS (11.45 µm) [click to enlarge]

Infrared Window images from POES AVHRR (10.8 µm) and Suomi NPP VIIRS (11.45 µm) [click to enlarge]

Shown below are two other types of satellite imagery that can be helpful for identifying the areal extent of transverse banding cloud features: the Suomi NPP VIIRS Day/Night Band (0.7 µm), and the MODIS Cirrus band (1.37 µm). A similar Cirrus band will be part of the ABI instrument on GOES-R.

Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

Terra MODIS Infrared Window (11.0 µm) and Cirrus (1.37 µm) images [click to enlarge]

Terra MODIS Infrared Window (11.0 µm) and Cirrus (1.37 µm) images [click to enlarge]

Mesoscale Convective System exhibiting cloud-top gravity waves and transverse banding

July 6th, 2012 |
Suomi NPP VIIRS 11.45 µm IR  + 0.7 µm Day/Night Band images

Suomi NPP VIIRS 11.45 µm IR + 0.7 µm Day/Night Band images

A comparison of AWIPS images of 375-meter resolution (projected onto a 1-km AWIPS grid) Suomi NPP VIIRS 11.45 µm IR channel data with the corresponding 0.7 µm VIIRS Day/Night Band (above) showed a large Mesocale Convective System (MCS) with an expansive cold cloud shield (exihibiting IR brightness temperatures as cold as -84 C) over parts of North Dakota and South Dakota at 08:43 UTC (3:43 AM local time) on 06 July 2012. A number of well-defined cloud-top gravity waves could also be seen propagating northward and northeastward outward away from the core of the storm. There was a damaging wind report at 09:03 UTC in south-central North Dakota:  SW WIND GUST OF 68 MPH AT 403 AM CDT...AND N WIND GUST OF 68 MPH AT 408 AM CDT. Illumination from a full moon made convective overshooting tops and some of these cloud-top gravity waves easy to see on the Day/Night Band image.

About 2 hours later, these cloud-top gravity waves wee more difficult to identify on a 1-km resolution POES AVHRR 10.8 µm IR image (below) at 10.32 UTC (5:32 AM local time), although a few could still be seen in eastern North Dakota, western Minnesota and southern Manitoba. There was a wind gust to 51 knots (59 mph) reported at 10:40 UTC in southeastern North Dakota.

POES AVHRR 10.8 µm IR channel image + METAR surface reports and severe wind reports

POES AVHRR 10.8 µm IR channel image + METAR surface reports and severe wind reports

As the MCS began to dissipate around sunrise, a vivid display of transverse banding cirrus filaments could be seen on 1-km resolution GOES-13 0.63 µm visible channel images (below; click image to play animation) forming along the southern periphery of the storm over eastern South Dakota, southern Minnesota, and far northern Iowa. This transverse banding is a satellite signature of potential high-altitude turbulence — and there was one pilot report of moderate turbulence at 38,00 feet in eastern South Dakota.

GOES-13 0.63 µm visible channel images (click image to play animation)

GOES-13 0.63 µm visible channel images (click image to play animation)