Thanks to recent dual-pol upgrades at area Doppler radar sites, we could also confirm the presence of tornadic debris. Here is a screen capture from the Mobile, AL radar at 5:13 pm as the tornado was moving through the West Hattiesburg/Oak Grove area. The more traditional radar products shown at the top (base reflectivity, storm relative velocity) were showing a severe thunderstorm, with strong and tight rotation at just over 7,000 feet above the ground. It was the dual-pol products on the bottom of this image that provided additional confirmation that this rotation must have been extending to the ground. The correlation coefficient (CC) product in the bottom-right helps to provide an idea of the consistency of the shape of the targets being reflected back to the radar. Higher values shows greater consistency (for instance, all rain), while lower values show less consistency (a mixture of targets). In this image we see an area of lower CC, which is actually an indication of tornadic debris of various shapes and sizes. In addition, the differential reflectivity product indicated values close to 0, which would also be expected with tornadic debris. Dual-pol continues to prove to be a powerful tool in our arsenal of technology enabling us to track severe weather.
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