Cloud

Question 1

Name the 4 types of low cloud

Answer 1

• Cumulus
• Stratocumulus
• Stratus
• Nimbostratus

Question 2

Name the 2 types of medium level cloud

Answer 2

• Altocumulus

* Altostratus

Question 3

Name the 5 types of high level cloud

Answer 3

• Cirrocumulus
• Cirrus
• Cirrostratus
• Cumulonimbus
• Towering Cumulus

Question 4

Which type of cloud is associated with moderate or heavy rain?

Answer 4

Nimbostratus

Question 5

Name the only 2 cloud types that are reported in the metar

Answer 5

• Towering Cumulus (TCU)

* Cumulonimbus (CB)

Question 6

Which type of cloud is ‘Cauliflower-Shaped’?

Answer 6

Towering Cumulus

Question 7

Which type of cloud is anvil shaped?

Answer 7

Cumulonimbus

Question 8

If reporting thunderstorms (TS), do clouds have to be present in the METAR?

Answer 8

Yes, one of either TCU or CB must be reported in the METAR when reporting TS.

Question 9

How are TCU or CB clouds reported?

Answer 9

They are reported after cloud amount and height as ‘TCU’ or ‘CB’

Question 10

What is the automated cloud sensor called?

Answer 10

Ceilometer

Question 11

What are the definitions of FEW, SCT, BKN and OVC?

Answer 11

They relate to the amount of sky, divided into oktas (8ths), covered by cloud.
• FEW - No more than 1/4 (1-2 oktas)
• SCT - Scattered - Between 1/4 and 1/2 (2-4 oktas)
• BKN - Broken - Over 1/2 but not full (5-7 oktas)
• OVC - Overcast - Complete cloud cover (8 oktas)

Question 12

How is cloud height reported, and what are the cloud rounding rules?

Answer 12

Cloud is reported in AGL, in 100’s of feet, rounded down to the nearest 100ft.

Question 13

What is the maximum height cloud that can be reported

Answer 13

4900ft (049). Cloud with a base of 5000ft or higher is not reported, unless it is TCU or CB.

Question 14

How does speed of clouds relate to its height?

Answer 14

Often, the faster the cloud is moving, the lower the cloud height.

Question 15

How is a cloud height of less than 100ft reported?

Answer 15

‘000’

Question 16

Are TCU and CB’s reported if their height is above 5000ft?

Answer 16

Yes. TCU and CB’s must be reported even if their height is above 5000ft.

Question 17

In what order are clouds reported?

Answer 17

They are reported in base height order, from lowest cloud to highest cloud, following the layer rules.

Question 18

How many cloud layers can be reported and what are the rules?

Answer 18

A maximum of 4 layers can be reported, subject to the following rules:
1st Layer : Report the lowest layer, whatever the amount.
2nd Layer : Only to be reported if the amount is 3 oktas or more (SCT, BKN, OVC)
3rd Layer : Only to be reported if the amount is 5 oktas or more (BKN, OVC)
4th Layer : Only to be reported as TCU or CB if omitted by the above rules.

Question 19

What is to be reported if CB and TCU cloud masses have a common base?

Answer 19

Report the sum of the amounts as CB.

Question 20

What is NCD?

Answer 20

No cloud discernible and it is only to be used by automated systems.