Satellite and radar images of the thunderstorm that produced this tornado, each at about the time the tornado was leaving Jarrell, are shown above. On the reflectivity image, a well-defined "hook" echo is visible; radar storm-relative velocity imagery (not shown) depicted a deep mesocyclone at the time the tornado was moving through Jarrell. Note the small cell just southwest of the Jarrell storm; this was one of several in the lifespan of the entire thunderstorm complex which formed farther southwest along the boundary, distinctly separate from the main storm -- then merged with it and became the primary storm itself. This process is known as discrete propagation and can be seen in the animated radar loop linked below.

Developing showers and thunderstorms, extending southwestward along the boundary from the main storm, are also evident on the visible satellite imagery. In addition, a faint gray arc moving southwestward across central Texas was possibly a gravity wave produced by a thunderstorm complex earlier that morning over eastern Oklahoma and Arkansas. The first thunderstorm of the Jarrell complex began where the arc intersected the low level boundary. This has renewed discussions among many meteorologists about the possible role of gravity waves in formation of severe thunderstorms.

A complete set of SPC radar and satellite imagery for the event is online in the form of animated gifs (NOTE: these files are large!), with text explanation:

Radar Reflectivity Loop - 475K Animated GIF

Vis Satellite Loop - 3.7 MB Animated GIF

A tornado watch from SPC had been in effect since 1:15 pm, and a tornado warning from NWS New Braunfels since 3:30 pm. [See text windows below.] Still, many of the people killed and injured had taken shelter properly within their dwellings but still did not survive because of the obliteration of those homes.

SPC Tornado Watch valid for Jarrell area