1 .		Most tornadoes in the central United States occur during the spring months when __________.
2 .		Which of the following is important to the formation of lightning in a developing cloud?
3 .		Hurricanes, tornadoes, and middle-latitude cyclones are similar in that they __________.
4 .		A significant portion of the growing-season rainfall in the agricultural regions of the central United States comes from __________.
5 .		A vertical cylinder of rotating air, typically about 3 to 10 kilometers across, linked to tornado formation in severe thunderstorms is called a(n) __________.
6 .		Thunderstorms are most likely to occur in the afternoon or evening because __________.
7 .		In order for a thunderstorm to be classified as severe by the National Weather Service, it must have winds in excess of _________ kilometers per hour.
8 .		If thunder is heard 10 seconds after lightning is seen, the lightning is about __________ meters away.
9 .		Atmospheric circulation in the immediate vicinity of a thunderstorm is __________.
10 .		The Fujita Intensity Scale is commonly used to assess __________ intensity.
11 .		An air-mass thunderstorm is most intense during the __________ stage.
12 .		The installation of _________ radar across the United States has significantly improved our ability to track thunderstorms and issue warnings based on their potential to produce tornadoes.
13 .		The terms flash, stroke, and leader, are all associated with __________.
14 .		__________ through __________ is the period of greatest tornado frequency in the United States.
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