Chapter 14 Thunderstorms

Question 1

what is a thunderstorm?

Answer 1

a storm containing lightning and thunder; convective storms

Question 2

what is a severe thunderstorm?

Answer 2

one of large hail (> 1 inch in diameter)
or wind gusts (over 50kts)
or tornado

Question 3

what are the stages of the ordinary cell thunderstorms?

Answer 3

1. cumulus stage
2. mature stage
3. dissipating

low wind shear, around an hour long, in warm locations

Question 4

what is the cumulus stage?

Answer 4

-growth stage
-updrafts form cloud which grows vertically
-no precip, no lightning or thunder

Question 5

what is the mature stage?

Answer 5

-precip starts
ENTRAINMENT: creates down draft, dry air sinks into open space
GUST FRONT: cold downdraft, reaches the surface, and spreads in all directions

Question 6

what is the dissipating stage?

Answer 6

-downdraft suppresses updraft, cloud dissipates from the bottom up

Question 7

what is a multi-cell thunderstorm?

Answer 7

-medium wind shear, multiple cells at once, one forms as one dies out

Question 8

how does a multi-cell thunderstorm work?

Answer 8

-tilted updraft from wind
-when down draft hits ground at angle, it allows for updraft
-lasts for hours

Question 9

what are microbursts?

Answer 9

localized downdraft, smaller and stronger

Question 10

what is a squall line?

Answer 10

line of thunderstorm, storm can develop ahead of front

Question 11

what is a derecho?

Answer 11

straight-line winds, happens in summer, very strong wind

Question 12

what is a mesoscale convective complex?

Answer 12

several individual multi-cell thunderstorms, not much movement

Question 13

what is a supercell thunderstorm?

Answer 13

very strong wind shear

-downdraft cannot suppress updraft
-one cell=hours
-thunderstorms form east of dry line

Question 14

what is lightning?

Answer 14

discharge of electricity in mature storms

Question 15

what is thunder?

Answer 15

explosive expansion of air due to heat from lightning

Question 16

how is a lightning strike formed?

Answer 16

1. stepped leader comes out of cloud to ground
2. upward streamer moves from ground to cloud
3. return stroke carries positive charge up into the cloud