Base reflectivity data at 0.5 degree elevation angle from the KLVX WSR-88D Doppler Radar. Reflectivity shows where and how hard it is raining or snowing, as well as precipitation intensity trends and movement. Blue and green colors represent light-to-moderate rainfall. Yellow and orange colors show moderate-to-heavy precipitation, while red is very heavy rainfall.
Above is a close-up view of an arcing line of thunderstorms called a "bow echo" or "bowing line segment" over Harrison County, Indiana (just west of Louisville, Kentucky) on August 13, 2011. The storm produced damaging winds along its path of movement over southern Indiana, and then across Jefferson County (and Louisville), KY, and from there on eastward. Bowman Field Airport (LOU) in Louisville reported a 69 mph wind gust as the line moved through the metro area. NWS forecasters are trained to identify bow echos, which are notorious in producing wind damage in favorable environments. At times, they also can produce transient (brief) tornadoes of EF0-EF2 intensity, although this bow echo produced wind damage only. An event summary on the August 13, 2011 event, including damage photos and radar imagery is available on our Science and Tech site.