Flashcards in Chapter 18 Deck (14):
1
Why do we care about thunderstorms?
they are a water resource, they redistribute heat and moisture in the atmosphere, and they cause lots of property damage and sometimes injuries/deaths.
2
What elements are required for thunderstorm formation
-A source of moisture
-A conditionally unstable atmosphere
-A mechanism to trigger the thunderstorm updraft
3
What must occur for a thunderstorm to be considered a severe thunderstorm?
-Hail >3/4" diameter
-Gusts of 50 knots or greater
-A tornado
4
Three stages of an airmass thunderstorm?
1. Cumulus stage - Warm Buoyant plume of rising air
2. Mature stage - Precipitation begins to fall from the thunderstorm
3. Dissipation Stage - The downdraft dominates the storm
5
Where do airmass thunderstorms typically form?
Deep within airmasses...Away from large scale fronts
6
What triggers an airmass thunderstorm?
Surface heating, lifting by mountains, or outflow from neighboring T-storms
7
What are the winds like in the environment where airmasses thunderstorms form?
Little to no vertical shear
8
Anvil?
The flat top of a thunderstorm that forms as the thunderstorm updraft hits the tropopause and spreads out horizontally
9
What are the prominant features of a Airmass Thunderstorm?
-Overshooting Top
-Anvil
-Mammatus Clouds
-Cold Pool
-Shelf Cloud
-Gust Front
10
Do thunderstorms with wind shear last longer?
Yes
11
What is a Mesoscale Convective System?
Mesoscale means a few to a few hundred kilometers (one t-storm to large groups of t storms)
12
How does the cold pool form?
Rainfall evaporation cools mid to upper troposphere air, which sinks to surface and forms a cold pool
13
What is a bow echo?
is a line, that turns into bow shapw with twics on the top, the big part of the twisting
14