Homework Questions #4:
Due: Monday, April 1
1. An unstable environment, one in which thunderstorms are likely to form, will be
______at the surface than aloft (steep environmental lapse
rate). In his way, rising air parcels stay ______than their environment
(are very “bouyant”) and thus rise quickly, creating a vigorous updraft.
2. What about the properties of the environment at the tropopause causes it to act like a
“lid” to this rising motion? (see the top of page 5 – II B 4. f. 2)
3. What are the three environmental conditions necessary for thunderstorms to form?
4. Ordinary (airmass) thunderstorms do not last long because, since they do not form in the
vicinity of the jet stream, they have an ______vertical configuration causing the ______to be superimposed on the ______.
5. Why are mesoscale convective systems (MCSs) [systems of grouped thunderstorms] so
critical to human life (in a positive way)?
6. Why do these groups of thunderstorms last so much longer than ordinary thunderstorms?
7. Thunderstorms are designated “severe” if they generate any one of what three conditions?
8. ______thunderstorms are by far the most intense and generate the
vast majority of violent tornadoes.
9. In question #3, note was made of three environmental conditions necessary for
thunderstorms to form. What is the fourth condition which enables “extreme” (question #7) thunderstorms to form?
10. This fourth requirement necessitates that these thunderstorms form in the vicinity of
______.
11. This fourth requirement enables the storm to tilt and ______, separating
the updraft from the downdraft and setting the stage for tornado formation.
12. These storms tend to form in the “______sector” of ECs, between the
cold front (or dry line) and warm front.
13. These four conditions, all superimposed in large quantity, are relatively unique to
______(geographical location) during ______(season) which make these extreme storms more numerous in this region than anywhere else in the world.
14. What is the fifth condition, also unique to this location, which contributes to the formation of
these storms by serving like a “lid on a boiling pot”?
15. The rotating updraft of one of these thunderstorms is called the ______.
16. The rotating cloud from which a tornado may eventually descend toward the ground is called
a ______.
17. Not much is known about tornado formation. What are the three reasons that they are
difficult to study?
18. The scale to categorize tornadoes based on the damage incurred by the winds is called the
______or______scale.
19. ______and ______tornadoes (~2% of all tornadoes) are responsible for 70% of
tornado deaths.
20. “Tornado alley” is located where?
21. The majority of tornadoes occur in this region (tornado alley) during what season?
22. During what time of day do tornadoes peak?
23. The radar hook echo is indicative of a ______. Doppler
radar detects ______in a thunderstorm.
24. A tornado watch means ______.
A tornado warning means ______
______.
25. Hail stones grow by collecting ______as they
get pushed up and down by the updraft and downdraft in a thunderstorm.
26. What is the most important impact of hail?
27. a) There has been a(n) ______in reported tornadoes since 1950?
b) What is the likely reason for this?
28. There has been a(n) ______in violent (F3 – F5) tornadoes since 1950?
29. a) There has been a(n) ______in tornado deaths since the early 20th
century?
b) Why?
30. The change in violent tornadoes with global warming to this point and the likely change in
atmospheric conditions necessary for tornado formation with further warming suggest a possible ______in supercell thunderstorm and tornado formation in the future.
31. Given the scale and complexity of tornado formation, as well as our limited understanding of
their behavior, any projection of change in number and intensity of these features in the warmer climates of the future is ______at best.
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