Precipitation

Question 1

main types of precipitation

Answer 1

rain, snow, sleet, hail

Question 2

size and velocity of typical cloud and rain droplet?

Answer 2

cloud: 0.02mm, 0.03ft/sec
rain: 2mm, 21.4ft/sec

Question 3

raindrops form from…

Answer 3

snowflake melt
collision and coalescence

Question 4

at what temp is cloud warm or cold?

Answer 4

warm cloud is above -5C, cold cloud is below

Question 5

collision and coalescence

Answer 5

precipitation droplets grow in the cloud via collision and coalescence and eventually grow large enough to precipitate

Question 6

how are snowflakes formed?

Answer 6

• requires supercooled water inside clouds
• form via Bergeron process

Question 7

Bergeron process

Answer 7

• ice crystals grow at the expense of water droplets in cloud with both ice and water
• water vapor droplets in air deposit on ice crystal, growing it

Question 8

rime ice

Answer 8

develops when supercooled water hits a solid surface and freezes on contact
- can result when planes encounter supercooled water

Question 9

graupel

Answer 9

forms when previously formed ice crystals collide with supercooled water droplets, we get riming on the crystals and a blob of ice forms

Question 10

sleet

Answer 10

essentially a raindrop that freezes solid
- formation requires temp inversion for

Question 11

freezing rain

Answer 11

raindrops freeze on contact with any frozen surface
- requires shallow temp inversion

Question 12

hail

Answer 12

associated with warmer weather, starts as graupel