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Meteorology

Meteorology. 5.04 Clouds and Fog References: FTGU pages 124-126, 147. 5.04 Clouds and Fog. MTPs: Cloud Classification Types and Recognition Associated Precipitation Fog Formation and Types. Cloud Classification. Clouds are classified by:. Height. Shape. and. Families.

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Meteorology

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  1. Meteorology 5.04 Clouds and Fog References: FTGU pages 124-126, 147

  2. 5.04 Clouds and Fog • MTPs: • Cloud Classification • Types and Recognition • Associated Precipitation • Fog Formation and Types

  3. Cloud Classification • Clouds are classified by: Height Shape and Families Type/Way They Form

  4. Cloud Classification • Two Cloud TYPES: Stratus Cumulus

  5. Cloud Classification • Four Cloud FAMILIES: • High (Cirro) • bases between 16 500 and 45 000 feet • Ice crystals • Middle (Alto) • Bases between 6500 and 23 000 feet • Ice crystals, water droplets - Low (Strato) • Bases from surface to 6500 feet - Clouds of Vertical Development • May form as low as 1500 feet • Water droplets above freezing

  6. Cloud Classification

  7. Types and Recognition • High Clouds 1. Cirrus (Ci) • very thin wispy cloud, like it was made with an artist’s brush • sometimes referred to as cats’ whiskers or mares’ tail • generally no particular significance to flying

  8. Types and Recognition • High Clouds 2. Cirrocumulus (Cc) • thin cotton like clouds • looks like pattern of the sand at a beach • no indication of future weather conditions

  9. Types and Recognition • High Clouds 3. Cirrostratus (Cs) • thin high sheet of cloud • sun or moon is visible, producing a halo effect • often indicate an approaching warm front or occlusion and therefore of deteriorating weather conditions

  10. Types and Recognition • Mid level clouds 1. Altocumulus (Ac) • layers of rounded masses of cloud that may lie in groups or lines • sometimes associated with an approaching front but usually they have little value as a weather predictor

  11. Types and Recognition • Mid level clouds 2. Altocumulus Castellanus (Acc) • altocumulus with turreted edges • may develop into cumulonimbus • a variation of AC with greater vertical extent • characteristics include: instability, turbulence and shower activity

  12. Types and Recognition • Low Clouds 1. Status (St) • uniform layer of low cloud resembling fog but is not touching the ground • low visibility, drizzle and fog often associated

  13. Types and Recognition • Low Clouds 2. Stratocumulus (Sc) • layer or series of rounded masses or rolls of cloud • common in high pressure areas in winter • sometimes gives a little precipitation

  14. Types and Recognition • Low clouds 3. Nimbostratus (Ns) ‘Nimbo’ – means precipitation is associated with the cloud • low dark grey layer • thickened altostratus • associated with warm fronts and continuous/steady rain or snow • may be more than 15,000 ft thick • VFR operations often difficult to impossible

  15. Types and Recognition • Clouds of vertical development 1. Cumulus (Cu) • Dense, thick, rounded and lumpy • resembles cotton balls • flat bases and sharp clear cut surfaces • forming during day and dissipate at night • height of base depends on temperature and dew point spread • light to moderate turbulence • NO PRECIPITATION

  16. Types and Recognition • Clouds of Vertical Development 2. Towering Cumulus (TCu) • a development of cumulus cloud • serious (moderate to heavy) icing and turbulence • rain showers and snow showers in winter • rough air underneath

  17. Types and Recognition • Clouds of Vertical Development 3. Cumulonimbus (Cb) • development of TCU • often anvil shape top • produces lightning and thunder • gusty surface winds in vicinity • hail is often present within the cloud and may occasionally fall from it • heavy icing, turbulence and showers • may be embedded in stratiform clouds • cloud should be avoided

  18. Confirmation • Name these clouds:

  19. Precipitation

  20. Fog Formation and Types • Fog is: • Cloud (usually stratus) in contact with ground • Formed when: • Air cooled to due point • Air becomes saturated (moisture added)

  21. Fog Formation and Types

  22. Fog Formation and Types 1. Radiation Fog (ground fog) • Forms at night • Initial heating from sun causes turbulence • Ground cools losing heat through radiation • Air in direct contact is cooled • Clear skies, moist air, light winds (2-5 knots)

  23. Fog Formation and Types 2. Advection Fog • When warm moist air moves over a colder land or sea surface • Winds >15 knots • Most frequent in costal regions • Widespread when moist air from warm region of ocean moves over colder water

  24. Fog Formation and Types Precipitation Induced Fog (frontal fog) • Addition of moisture to air through evaporation of rain or drizzle • The precipitation from warm air evaporates and saturates cooler air below • Associated mostly with warm fronts

  25. Fog Formation and Types 4. Upslope Fog • Cooling of air due to expansion as it move sup slope • Light upslope wind required

  26. Fog Formation and Types Steam Fog • Cold air passes over warm water surface • Evaporation of water into air until saturated • Occurs over rivers and lakes, especially during autumn

  27. Fog Formation and Types Ice Fog • Moist air during extremely cold calm conditions • The cold air cannot hold more moisture and excess sublimates into ice crystals • Crystals appear suddenly when engine started • Water vapour • Condensation nuclei • Mixing agent

  28. Confirmation • Watch the link: • http://www.youtube.com/watch?v=KG0i-AsaGO4 • What clouds can you name?

  29. Confirmation • What are the names for the 3 levels of clouds? • Name one type of cloud of vertical development. • What requirements are needed to create fog? • What type of precipitation would you get in: • i) stratus clouds • Ii) cumulus clouds

  30. Nacreous Clouds may be found above the poles, and are actually in the Stratosphere

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