Bright reds, oranges and yellows show tracks of where rotation was strongest as detected by NWS Doppler radars during the April 27, 2011 tornado outbreak.

NSSL has released an image documenting the rotation tracks of the devastating tornadoes on April 27. Bright reds and yellows show more intense circulations.

The image of the rotation tracks was produced by the On Demand Severe Weather Verification System, part of NSSL’s Warning Decision Support System – Integrated Information (WDSS-II) Multi-Radar/Multi Sensor platform. On Demand is a web-based tool that can be used to help confirm when and where severe weather occurred.

On Demand uses data gathered and sorted by WDSS-II to estimate the tracks of rotating storms and where hail fell. The rotation tracks or hail swath data can be overlaid on high-resolution street maps in Google Earth/Maps to pinpoint areas affected by the hazardous weather.

The WDSS-II system receives data in real-time from the nationwide networks of weather radars, satellites, surface observations and lightning detectors. WDSS-II then processes, analyzes and displays the data in a way that is useful to people who need to diagnose severe weather quickly.

The platform is being used by several local American Red Cross chapters, emergency managers and National Weather Service Forecast Offices for disaster assessment and response.

The April 27 Rotation Tracks file is available here for downloading and overlay on Google Earth:  http://ondemand.nssl.noaa.gov/RotationTrack1440min_20110428-085936.kmz