1- The conditions which must exist to allow thunderstorms to develop are:
A trigger action, a plentiful supply of moisture and a very stable atmosphere.
A steep lapse rate, a stable atmosphere through a large vertical extent and a plentiful supply of moisture.
A plentiful supply of moisture and a steep lapse rate through a large vertical extent and a trigger action.
A steep lapse rate through a large vertical extent, a low relative humidity and a trigger action.
2- Hazards of the mature stage of a TS cell include lightning, turbulence and:
Microburst, windshear and anvil.
Icing, microburst and windshear.
Icing, drizzle and microburst.
Windshear, hail and fog.
3- Thunderstorms require a trigger action to release the conditional instability. Which of the following woud be the least suitable as a trigger:
Covergence in temperate latitudes.
Convergence in tropical latitudes.
Subsidence in tropical latitudes.
Convection in polar latitudes.
4. During the _____ stage of a thunderstorm cell, the cloud contains _____ . Complete the above statement correctly using one o
Building / up currents and down currents.
Mature / up currents and down currents.
Dissipating / up currents and down currents.
Building / down currents only.
5- The following is unlikely to be a hazard below a thunderstorm:
Severe turbulence.
Severe icing.
Windshear.
Large variations in pressure setting values.
6- Thunderstorms are likely if:
Air is unstable, there is sufficient water vapour and there is a trigger action.
Air is completely stable, there is sufficient water vapour and there is lifting orographically.
There is a warm front.
There is a col in winter.
7- Hail grows by:
Freezing as it leaves the cloud.
By up and down progress in CU cloud.
By collision with supercooled water drops.
By collision with ice crystals.
8- How long approximately does a Cumulonimbus cell take to complete the full cycle from the Cumulus (building) to dissipating stage?
2-3 hours.
1-2 hours.
4-5 hours.
About 1 hour
9- A microburst usually lasts for _____ and is about _____ across.
20 minutes. 20 nm.
5 minutes. 5 km.
30 minutes. 10 km.
45 minutes. 5 nm.
10- When flying through an active CB cloud, lightning strikes are most likely:
Above 5000' and underneath the anvil.
In the clear air below the the cloud in rain.
In the temperature band between +10ºC and -10ºC.
At about 10000 ft above AMSL.
