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What do roll and wall clouds indicate?

The presence of low level wind shear and extreme turbulence


A ______ forms on the surface at the leading edge of an advancing thunderstorm.

gust front


Microbursts are an intense, highly localized downward atmospheric flow with velocities of ______ to over ______ feet per minute

2000; 6000


What methods can be used to detect a microburst?

a. Visual cues
b. Wind shear alert systems
c. Pilot Weather Reports (PIREPs)
d. Departure/Arrival weather reports


Why do you want to fly over the top, at least 1000 feet per knots of wind speed at cloud top level, to void a thunderstorm?

Because it allows an altitude margin for turbulence and hail.


Why do you want to penetrate the lower ⅓ of a thunderstorm?

Because most storms are most severe in top 2/3 of a cell.


What combination of atmospheric conditions is necessary for the formation of a thunderstorm?

a. Moisture
b. Unstable air
c. Lifting action


What effects can turbulence have on an aircraft?

a. Changes in altitude
b. Structural damage
c. Extra stress on the airframe
d. Effect depends on severity of turbulence and speed of aircraft


What hazards are associated with lightning?

a. Static charge builds up in the aircraft
b. Can strike aircraft flying in the clear
c. Structural damage
d. Catastrophic fuel ignition
e. Pilots can experience flash blindness


If a thunderstorm is approaching do not ______ or ______.

takeoff; land


Why do you want to penetrate a thunderstorm perpendicular?

To minimize time in the storm


What hazards to flight are associated with thunderstorms?

a. Hail
b. Turbulence
c. Lightning


Three requirements for thunderstorm development are:

Unstable air
Lifting action


Regarding tornados, what are the three cloud types:

Tornado touches ground.
Funnel cloud - not touching surface.
Waterspout - touches water surface.


What are the downward atmospheric flow velocities and outflow wind shears velocities accosiated with microbursts?

Downward atmospheric flow with velocities of 2000 to over 6000 feet per minute
Outflow produces wind shears of 20 to 200 knots.


What is the area span, duration and type of clouds associated with microbursts?

Area only ¼ to 2 ½ miles wide
Lasts only 5-10 minutes
Emanates from cumuliform cloud, not necessarily a thunderstorm.


What is Virga?

Virga is a visual cue of microburst, where precipitation from the cloud evaporates before reaching the ground.