The Tornado Prediction Center issues three kinds of watches.
The Enhanced Tornado Watch box is a magenta colored box. This box means nearly the same as NOAA's PDS Tornado Watch box in that strong to violent tornadoes in numbers are possible with some being of long track. On June 11th, 2008 the TPC issued such a watch in and around the area the Boy Scout camp in Iowa got hit. The watch was issued 7 hours before NOAA put it out. People that visit the prediction center get these very early watches for that very reason. Here is a SCREENSHOT of the watches issued 7-12 hours before NOAA issued theirs.
The Tornado Watch box is red. This is a slightly lower probability than the enhanced tornado watch box and still yields a chance of strong tornadoes. The box is issued when tornado dynamics are high enough for possible touchdowns.
The Tornado Advisory is yellow. This box is not as SPC has it and they do not own a low-grade box name. The advisory is for weaker tornado dynamics with the chance of weak or isolated tornadoes in the box.
When a tornado watch is expiring or expired, the box will close up from the original issued to show you where it once was. A dotted line feature will be where it is not active anymore. A solid box means active. |
