1.   Hail forms as wind blows water droplets high inside a thunderstorm cloud and the drops freeze, then fall.

2.   His often-terrible moods were like thunderstorm clouds.

3.   Rotating motions detected by radar in thunderstorm clouds led forecasters to alert mariners for possible waterspouts off the southern California coast on Monday.

4.   These columns of air extend from a thunderstorm cloud to the ground.

5.   They agree that somehow, positive and negative electric charges are segregated within and around dark, mountainous, rain-whipped cumulonimbus clouds -- thunderstorm clouds.

6.   Despite a worsening forecast, NASA aimed for a Friday evening launch of space shuttle Endeavour after thunderstorm clouds forced a one-day delay.