Met 3 (Clouds) Flashcards
How are clouds formed by frontal / mass ascent?
Formed when a mass of warm air rises over a mass of cold, dense air over large areas along fronts.
How are clouds formed by turbulence and mixing?
Turbulence caused by eddies means air mixes. Air in rising currents cools and hits its dew point and condenses forming clouds.
How are clouds formed by mountain/standing waves?
Air flowing over mountains rises and cools. If it hits its dew point clouds are formed.
List 4 ways clouds can form?
- Convection
- Mass Ascent
- Turbulence
- Orographic (mountain waves)
How are clouds formed by convection?
The ground is heated by the sun. The ground then heats the air causing thermals forming clouds.
What are the 4 main cloud groups?
- Cumulus
- Stratus
- Cirrus
- Nimbus
How can you identify a cumulus cloud?
Heaped or in a pile.
How can you identify a stratus cloud?
In a sheet or layer.
How can you identify a cirrus cloud?
Thread-like or wispy.
How can you identify a nimbus cloud?
Grey, rain bearer.
What are the 3 cloud height groups?
- Cirrus/Cirro
- Alto
- Low cloud
What height are cirrus/cirro clouds?
20,000-45,000ft
What height are alto clouds?
6,500-20,000ft
What height are low clouds?
Surface-6,500ft
What would be reported for 0 Oktas?
Sky clear (SKC)
What would be reported for 1-2 Oktas?
Few (FEW)
What would be reported for 3-4 Oktas?
Scattered (SCT)
What would be reported for 5-7 Oktas?
Broken (BKN)
What would be reported for 8 Oktas?
Overcast (OVC)
What would be reported for no clouds below 5,000ft or Tcu/Cb?
No significant clouds (NSC)
What methods could be used to estimate cloud base?
- Ceilometer/cloud base recorder
- Search light
- Timed balloon ascent
- Pilot report
- Visual estimates
What is stable air?
A parcel of air that tends to return to its original level.
What is unstable air?
A parcel of air hat is warmer than its surroundings will continue to rise.
