Researchers in Norman, Oklahoma are spinning the largest web ever to catch tornadoes. By next month, the largest net of weather instruments ever deployed to track tornado development will be spread across the Southern Plains as the season arrives. In its second year of field activity, the Verification of the Origin of Rotation in Tornadoes Experiment (VORTEX) from April 1 to June 15 will target supercells or long-lived severe thunderstorms with circulation patterns that are ripe for producing tornadoes. Less than 50% of such supercells actually produce tornadoes. On any given day, VORTEX will deploy about 20 instrument-studded vehicles around a supercell and follow the storm for several hours. Aboard each of the vehicles are compact weather stations that use Global Positioning System technology to report weather data every few seconds.