Precipitation

=**__Precipitation__**  = When cloud particles become too heavy to remain suspended in the air, they fall to earth as precipitation. Precipitation occurs in many forms; rain, freezing rain, hail, sleet or snow. Elevation and geography play a major roles in determining these types of precipitation.

//Rain// //When condensing droplets that form the cloud get large and heavy enough to overcome the upward pressure of convection, they begin to fal L. If the temperature all the way to the ground is freezing than it's raining.Commonly formed by nimbostratus or stratus clouds. For// **rain** //to form, water vapors require a "condensation nucleus", which can include tiny particles of dust or pollen, swept high into the atmosphere.//

//Freezing Rain//
 * Freezing rain** //most often occurs when mild, moist air moves over a cold polar or arctic air mass near the earths surface. A shallow layer of cold air lies below a layer of warmer air, which completely melts all ic e particles as they pass through. When the raindrops enter the shallow layer of cold air, they super cool and freeze instantly on contact.//

//Hail// //Hailstones start out as an ice nucleus, or a small cluster of supercooled water droplets or clumps of snow. These ice nucleus's get blown through freezing thunderclouds and may get melted or re frozen over and over again forming layers until it gets hea v y enough to drop.//

//Sleet// //Falling frozen precipitation are ice pellets. As snowflakes pass through a layer of warm air they melt into raindrops, as they reach near the earths surface and enter the sub-freezing a i r than refreeze into ice particles.//

//Snow ' Frozen precipitation; snow is a a six-sided ice crystal structure. From the surface of the earth to the level of clouds snow requires temperatures to be below freezing in 90-100% of the atmosphere. S now however can fall still when temperatures are above freezing but in shallow layers.//

Bibliography

http://en.wikipedia.org/wiki/Precipitation_%28meteorology%29 http://ww2010.atmos.uiuc.edu/%28Gh%29/guides/mtr/cld/prcp/home.rxml http://www.wxdude.com/page3.html