Cloud And Triggers

Question 1

What do stable conditions create in terms of clouds

Answer 1

Clouds with flat tops and the stratus types with poor vis an d continuous rain

Question 2

What do unstable conditions and lots of moisture create in terms of clouds

Answer 2

Towering clouds as warmer air than surrounding rises higher
The cumulus type with short showers and good vis

Question 3

What are the appearance classifications of clouds

Answer 3

Startiform and cumuliform clouds and cirriform

Question 4

Examples of stratiform clouds

Answer 4

Horizontal flat, stable clouds that produce continuous rain
Eg. Stratus, Nimbostratus, Altostratus and Cirrostratus

Question 5

Examples of Cumuliform clouds

Answer 5

Vertical in the form of heaps and lumps that are individual and separated
Eg. Cumulus, Stratocumulus, Altocumulus

Question 6

What the different heights of cloud bases

Answer 6

Low = 0-6500ft
Med = 6500-23000ft
High = 16500ft

Question 7

What are the typical heights for cumulus and cumulonimbus clouds

Answer 7

Cumulus 1500-6500ft +
Cumulonimbus 1000 - 6500ft +

Question 8

Where are cloud bases measured from

Answer 8

The surface which you are stood on

Question 9

Properties of cumulonimbus

Answer 9

Heavy and dense cloud
Mod - Sev Icing and Turbulence
Potential for thunderstorms
High vertical extent through multiple layers

Question 10

Properties for cumulus cloud

Answer 10

Dense and sharp outlines
Cauliflower top/bulging out
Brilliant white colour
Heavy rain, storms and turbulence

Question 11

What is the difference between unstable and stable cumulus

Answer 11

Unstable is Towering Cu which could turn into Cb
Stable is Fair Weather Cu

Question 12

Properties of stratocumulus cloud

Answer 12

Globular masses and rolls
Covers a wide area and thick
Light icing and light rain

Is a result of turbulence/formed by surface layer friction

Question 13

Properties of stratus

Answer 13

Uniform and shallow layer
0/little precipitation - maybe drizzle

Question 14

Properties of nimbostratus

Answer 14

Wide and deep
With frontal systems
Mod-sev rain and icing and continuous

Question 15

Properties of altostratus

Answer 15

Weaker but similar to Ns
Rain might not reach the ground - Virga
Weak sunshine

Question 16

Properties of altocumulus

Answer 16

Lumpy clouds in thin layer
No significance

Question 17

Properties of cirrus family

Answer 17

All composed of ice crystals but icing is not a problem
Delicate/wispy clouds that have full/ partial covering

Question 18

Other species of cloud

Answer 18

Virga
Capillatus
Calvus
Lenticularis
Castellanus
Congestus

Question 19

What clouds are the following
Ice clouds
Mixed clouds
Pure water

Answer 19

Cirrus
Cumulonimbus
Nimbostratus

Question 20

How do clouds dissapate

Answer 20

An increase in temp
Cloud mixing with drier air
Air sinking within cloud
Higher wind speed

Question 21

How do you measure clouds

Answer 21

Ceilometer
Octas (0-8)

Question 22

What is the octas scale

Answer 22

0 - sky clear
1-2 Few
3-4 Scattered
5-7 Broken
8 Overcast
Could also have layered

Question 23

Definition of cloud base

Answer 23

Height of the bottom layer of cloud

Question 24

Cloud ceiling

Answer 24

The height of the lowest layer of cloud below 6000m and covering more than half of the sky

Question 25

Cloud of operational significance

Answer 25

When the cloud is either below 5000ft or below minimum Sector altitude Whichever is the greater value

Question 26

How do clouds form

Answer 26

Adiabatic cooling Air forced to rise then becomes saturated and condenses The amount of hygroscopic nuclei

Question 27

What factors cause air to rise

Answer 27

Orographic uplift Convection Turbulence Frontal uplift Convergence Thin layer lifting