21.   High level winds from the Southwest allowed mild, moist air to rise over the chilly air, producing clouds of almost every variety.

22.   In the West, air pressure tends to be lowest during the summer months, when warm air, being buoyant, rises, lowering the surface pressure.

23.   In turn, heated air rose rapidly, forming thunderstorms.

24.   In turn, warm, moderately humid air will rise into gathering cold air aloft, raising the risk of thunderstorms.

25.   Like a hot-air balloon, air then rises to form storms.

26.   Like a hot-air balloon, the air then rises, and, if there is sufficient moisture, blossoms into a roiling cumulus cloud.

27.   Moist air rises over the stalled air and can drop more rain than might be expected otherwise.

28.   Meanwhile, heavy rain, punctuated by thunder in some areas, will pelt southeast Texas as humid air rises into a steadily cooling upper atmosphere.

29.   Several thundershowers will develop in the Appalachians as sultry air rises over the mountains.

30.   That air must rise until it has cooled to the temperature of the air around it.