An Amazing High-Resolution Radar Look at a Tornado

Jon Erdman
Published: March 3,2017
A spectacular high-resolution image from a research Doppler radar of one of 2016's most notable tornadoes provides stunning detail not typically seen in conventional radar.
(MORE: Tornado Central)
Trevor White, a scientist at the Center for Severe Weather Research (CSWR) in Boulder, Colorado, tweeted the image of the May 24, 2016, Dodge City, Kansas, tornado last week.
The image was acquired from a Doppler on Wheels (DOW7) mobile dual-polarization radar scanning the supercell.
What's shown in that image is not strictly where the heaviest precipitation is occurring, a parameter you most often see known as reflectivity, but rather a parameter called correlation coefficient (CC).
Among other uses, CC is used to detect debris lofted by a tornado. Airborne tornado debris consists of items with vastly different sizes and shapes, falling to the ground much differently than precipitation.
This is what the CC parameter picks up on, shown in the Dodge City example as a blue dot in the middle of a very pronounced hook echo.
(MORE: The Challenge of Tornado Warning False Alarms)

Dual-polarization (correlation coefficient) zoomed-in radar image from the Doppler on Wheels (DOW7) mobile radar of a tornado near Dodge City, Kansas, on May 24, 2016, at 6:05 p.m. CDT.
(Used with permission: Trevor White/TWIRL - supported by NSF)

The tip of that hook echo encircling the lofted debris is the tornado itself.
At one time this supercell spawned twin tornadoes, which passed unnervingly close to Dodge City and prompted a rare tornado emergency.

A tornado is seen south of Dodge City, Kansas, moving north on May 24, 2016.
(Brian Davidson/Getty Images)

Funded by the National Science Foundation, the CSWR sampled several tornadoes in late spring 2016 as part of the Tornado Winds: In situ and Radar observation at Low Levels, or TWIRL, field program.
For more interesting mobile radar images, photos, and chase logs from the 2016 TWIRL field program, check out the CSWR TWIRL mission page.
All National Weather Service Doppler radars were retrofitted for this dual-polarization technology by spring 2013, which includes the capability to detect lofted tornado debris, among other benefits.
Jonathan Erdman is a senior meteorologist at weather.com and has been an incurable weather geek since a tornado narrowly missed his childhood home in Wisconsin at age 7.