THE NATIONAL WEATHER SERVICE
'(<a href="http://www.j-archive.com/media/2008-11-26_J_30.jpg" target="_blank">Kelly reads the clue.</a>) Many tornadoes develop from a special kind of thunderstorm called this, with a <a href="http://www.j-archive.com/media/2008-11-26_J_30a.jpg" target="_blank">deep rotating updraft</a>'
a supercell