Thunderstorms Flashcards
What cloud type is a thunderstorm cloud?
Cumulonimbus
What characterizes the mature stage of the life cycle of the thunderstorm cell?
Both updrafts and downdrafts
What cloud type is the anvil top of a thunderstorm cloud and what is it made of?
Cirrus, ice crystals
What is associated with a gust front?
An intense thunderstorm
What does the appearance of a flat anvil top on a developing thunderstorm cloud indicate?
It has reached an extremely stable portion of the atmosphere
What characterizes the dissipating stage of the life cycle of a thunderstorm cell?
Downdrafts only
What is a mesoscale convective complex (MCC)?
A thunderstorm that consists of numerous interacting thunderstorm cells
Where does a squall line usually form?
In the mT air along or ahead of a cold front
Where is thunderstorm development most favoured?
By conditionally unstable maritime tropical air
What are the characteristics of thunderstorm cells associated with a fast-moving, well-defined cold front?
- May be severe
- Often occur as a squall line parallel to and ahead of the front
- Often form an elongated cluster parallel to the front
What triggers thunderstorm development?
- Uplift along a well-defined cold front
- Converging surface winds
- Uplift of warm, humid air along mountain slopes
- Forced convection
What is a feature sometimes present in thunderstorms that may prolong the mature stage?
A tilted updraft
What sector of a mature extratropical cyclone is a supercell thunderstorm most likely to develop?
Southeast
What may accompany a severe thunderstorm cell?
- Hail
- Damaging winds
- Heavy rainfall
- Frequent lightning
What is a dry line and where does one often occur?
-A site for the development of a severe thunderstorm cell
-Separates hot, dry air from warm, humid air
Often occurs over Texas and Oklahoma
What is a gust front?
The leading edge of a mass of cool, gusty air formed as the downdraft exists the base of a thunderstorm cloud, strikes the ground, and spreads laterally
How can a gust front spur the development of secondary thunderstorms?
The advancing gust front acts like a miniature cold front, forcing humid air ahead of the front to rise, and ascending humid air may spur the development of a secondary thunderstorm
What is the difference between a sea breeze front and a gust front?
A horizontal pressure gradient arising from differential heating between land and water generates a sea breeze front, whereas a gust front is the consequence of a thunderstorm downdraft
What causes the anvil shape of a thunderstorm top?
Strong winds aloft help shape the anvil top of a thunderstorm cloud. The flat top of the anvil is produced when the rising cloudy air encounters the very stable air of a tropopause and lower stratosphere.
Why might a cloud bulge on the anvil top of a thunderstorm suggest a severe thunderstorm?
The cloud bulge is the product of an exceptionally vigorous updraft and usually indicates an intense thunderstorm.
What is the cumulus stage of a thunderstorm cell?
The first stage of the life cycle of a thunderstorm cell where the cumulus cloud is building vertically and merges laterally as the developing system features a strong updraft.
What is the mature stage of a thunderstorm cell?
Is the second stage of the life cycle of a thunderstorm cell where precipitation develops and the system exhibits both an updraft and downdraft.
-Lightning, thunder, strong gusty winds, and maybe hail occurs during this stage
What is the dissipating stage of a thunderstorm cell?
The last stage of the life cycle of a thunderstorm cell where the downdraft starts to spread throughout the thunderstorm cloud. Precipitation tapres off and ends, and clouds begin to vapourize.
