Climatology/Precipitation

Precipitation is the falling of water from the sky in different forms. They all form from the clouds which are located about 8 to 16 kilometers above the ground in the earth’s troposphere. The process of precipitation represents falling down of this condensed material in the form of rain, snow, hail, sleet or some other forms.

Forms of Precipitation
Precipitation occurs in many forms or phases such as :-
 * 1) Liquid precipitation (Drizzle and rain),
 * 2) Freezing precipitation (freezing drizzle, freezing rain and sleet) and
 * 3) Frozen precipitation (snow, ice pellets and hail etc.).

Rain
Rain is any liquid that drops from the clouds in the sky, in the form of liquid.There size described as water droplets of 0.5 mm or more than 0.5mm.Rainfall rates vary from time to time.tropical areas, cumulus clouds rain is the result ofcollision and coalescence process. In temperate areas, most rainfall is produced by nimbostratus clouds. The vertical clouds, cumulonimbus produce heavy rainfall with lightning and thunder.

Drizzle
Drizzle represents light liquid precipitation in the form of uniform water droplets of diameter less than 0.5 mm.It associated with stratus, nimbostratus and stratocumulus clouds.Precipitation in the form of drizzle continues for several hours or occasionally for days.It is the most frequent form of precipitation over subtropical Oceans.

Snow
Snow represents precipitation in the solid form of water.It is precipitation in the form of virga or flakes of ice water falling from the clouds.Snow is normally seen together with high, thin and weak cirrus clouds.Snow has fluffy, white and soft structure and its formation is in different shapes.

Sleet (Ice Pellets)
when snow falls into a warm layer then melts into rain and then the rain droplets falls into a freezing layer of air that is cold enough to refreeze the raindrops into ice pellets.sleet is defined as a form of precipitation composed of small and semitransparent balls of ice.

Freezing Rain
Freezing rain occurs when raindrops pass through the subfreezing air near the surface, the raindrops become supercooled and freeze when they strike on surface features.

Snow Pellets
It consist of small, white and opaque compact grains of ice. The grains are mostly spherical and have a diameter of 2–5 mm. Snow pellets are also known as soft hail. the grains are brittle and bounce and break after striking surface.

Hail
Hailstones are big balls and irregular lumps of ice that fall from large thunderstorms.mostly diameter between 1 cm and 5 cm. Its size depends on the content of ice and snow it acquires while falling down. Hailstones are common in violent summer thunderstorms.hailstones are formed from super-cooled droplets that slowly freeze and results in sheet of clear ice.