Using Routine, 15-minute-scan, Visible Imagery

  Strong thunderstorms form on low-level boundaries such as cold fronts, drylines, outflows, etc.   These boundaries are frequently marked by organized lines of cumulus cloudiness.   By monitoring pre-existing cumulus lines with satellite imagery, forecasters can focus their attention on specific, preferred regions of potential storm formation.

  This loop shows a large thunderstorm developing in eastern TX on 27 May 1997.   It developed on, and travelled along, a pre-existing line of towering cumulus which had formed along a cold front.   This storm produced a family of tornadoes, the most destructive of which occurred at Jarrell, TX.

  To start the looping process, click on "Forward"; to stop it, click on "Stop".   Allow the loop to cycle once or twice to get up to speed.