1. 18.3 Cloud types and Precipitation Clouds are classified on the basis of their form and height Clouds are classified on the basis of their form and height – –

2. 18.3 Cloud types and Precipitation Cirrus Cirrus Feathery appearance Feathery appearance Cumulus Cumulus –Flat base, with rising domes –“_____________” structure

3. 18.3 Cloud types and Precipitation Stratus Stratus Cloud height Cloud height –High clouds – _________ meters and above –Middle clouds – ________________ meters –Low clouds – _____________ meters

4. 18.3 Cloud types and Precipitation High Clouds High Clouds –cirrus –____________ All thin and white and made mostly of ice crystals All thin and white and made mostly of ice crystals

5. 18.3 Cloud types and Precipitation Middle clouds Middle clouds –Use the prefix –______ ___________ ___________ – Low clouds Low clouds –____________

6. 18.3 Cloud types and Precipitation ________________ clouds – “thunderheads” ________________ clouds – “thunderheads” Fog – clouds that form at ground level Fog – clouds that form at ground level –May be caused by _________ or ___________

7. 18.3 Cloud types and Precipitation How precipitation forms How precipitation forms –Cloud droplets must grow in volume by ______________ –Cold Cloud Precipitation Bergeron – relies on 2 processes Bergeron – relies on 2 processes –______________ and __________________ –Water in liquid state below 0 degrees Celsius is supercooled –When air is at 100% humidity it is satured to water, and supersaturated to ice  _____________________

8. 18.3 Cloud types and Precipitation Warm cloud precipitation – Warm cloud precipitation – –______________________ process Water absorbing particles remove water vapor from the air at relative humidities _________________ Water absorbing particles remove water vapor from the air at relative humidities _________________ Drops formed are quite large, they fall, and coalesce with smaller, slower drops Drops formed are quite large, they fall, and coalesce with smaller, slower drops

9. 18.3 Cloud types and Precipitation Forms of precipitation Forms of precipitation –Depends on the _____________________________________ __________: drops with a diameter of at least 0.5 mm __________: drops with a diameter of at least 0.5 mm __________: smaller drops of precipitation __________: smaller drops of precipitation __________: solid drops made of 6-sided ice crystals __________: solid drops made of 6-sided ice crystals __________: falling of small particles of ice __________: falling of small particles of ice __________: freezing rain __________: freezing rain __________: begin as small ice pellets and grow by collecting supercooled droplets as they fall to the ground __________: begin as small ice pellets and grow by collecting supercooled droplets as they fall to the ground