|Radar Image 7 pm August 19, 2011|
|Storm Rainfall Accumulation August 19, 2011|
|Severe Storm Reports August 19, 2011|
|Lightning Totals August 19, 2011 (123,000 Discharges Detected)|
This radar image shows a line of powerful thunderstorms that swept through the metro region during the early evening of August 19. The storms arrived from the northwest and were generated ahead of an upper level disturbance (a shortwave trough). With plenty of unstable air and abundant moisture, the storms generated local flash floods and intense lightning. However, wind shear (the change in wind speed and direction with height) was very weak. Because of these light winds, the storms moved very slowly, allowing heavy rain to accumulate and pond. And because strong wind shear is usually a factor in generating widespread damaging winds, large hail and tornadoes, there were only scattered reports of these types of severe weather.