Precipitation To get precipitation, you first must cool the air to the dew point: RECC: Rising Air Expands Cools, Condenses So…..one sure way to get air to the dew point is to lift it up

There are 4 primary ways that air gets lifted in the atmosphere 1. A hot spot

Typical cloud formation from hot spot Adiabatic means to change temperature by expanding or compressing air

2. Clouds often form along mountain ridges from this type of lifting Clouds and rain fall on windward side of mountain

windward leeward desert Or 10ºC/km Or 5ºC/km The next slide will show dramatically the windward/leeward differences

Cascade Mtns.

Windward Side

Leeward Side

3. this happens all along the equator N. Trade Winds S. Trade Winds

4. cold front Warm front When warm and cold air meet, the warm air is lifted over the cold air

Types of Precipitation Rain: drops of water falling from sky Snow: ice crystals falling from sky Sleet: raindrops freeze to ice pellets while falling from the sky Freezing rain: raindrops freeze when they hit the ground or land on an object Hail: large ice balls that form during thunderstorms

Warm rain in Belize, near the equator is common in the late afternoon

Away from the tropics, rain often starts in clouds as snow flakes snowflake melts into rain refreezes into sleet sleet or freezing rain is determined by how long the rain drop falls through sub-freezing temperatures If it is cold enough all the way down, the snowflakes land on the ground as snow If it warms up on the way down, the flakes may melt into rain If the rain freezes before it hits the ground it is sleet if it freezes when it hits the ground it is freezing rain

freezing rain is very destructive

Hail Hail commonly forms in severe thunderstorms