Precipitation Drop formation: nucleus, cloud droplet (gravity down, updraft up),  supercooled; collision coalescence;  ice-crystal process, accretion, aggregation, fracturing
  rain / drizzle (<1/2mm): often starts as snow; stratus clouds - gentle updrafts - small drops - continuous rain; towering cumulus - strong updrafts - big drops - abrupt storm with sharp edges, virga

snow - table 8.3: warm - initial rain evaporates to form snow, shapes - dendrite, snow pellet - cold wet clouds, freezes water but bounces off ice, rime coating

sleet and freezing rain: warm air over cold surface layer

hail: cumulonimbus, requires very strong updrafts, repeated trips through cloud, supercooled water droplets accreted, cloud seeding reduces size
 
Explain how raindrops form (2 methods). What do the shapes of snow tell about temperatures of formation.

Compare and contrast the main types of precipitation: rain, snow, sleet, freezing rain, hail.
 
 
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