11.   Farther south, a broken band of strong thunderstorms may spawn a few tornadoes in the warmer and more humid air over central and eastern Texas.

12.   Even as the storm continued losing strength, it downed trees, knocked out power and spawned small tornadoes in Virginia early Saturday morning that injured nine people.

13.   Frequently, however, the severe thunderstorm that spawns a tornado can be much more long-lived.

14.   Isolated supercells, which are individual, massive thunderstorms, may spawn a few tornadoes.

15.   It was a rare move because hurricane aircraft almost never fly over land, where the storms can spawn tornadoes.

16.   Moist air from the Gulf of Mexico, dry air from the West and cold air from Canada join over the midsection to spawn tornadoes.

17.   Measurements that researchers had thought would help predict when a storm system was about to spawn a tornado turned out to be useless in some cases.

18.   On Monday, the moisture-laden disturbance that spawned the tornado drifted into the region from the southeast.

19.   On Saturday a late-summer disturbance spawned tornadoes that ripped through northern Indiana.

20.   On Sunday, severe thunderstorms that spawned tornadoes erupted over West Texas along a dry line.