Posts Tagged "Precipitation"

Nimbostratus

Posted by on May 15, 2011 in phenomena | 15 comments

Nimbostratus

Tweet Heads, Australia.

Nimbostratus clouds are dark gray with a ragged base. Rain or snow is associated with Nimbostratus clouds.

{boatsafe.com, picture from mustang00069}

A Nimbostratus cloud is characterized by a formless cloud layer that is almost uniformly dark gray. “Nimbo” is from the Latin word “nimbus”, which denotes precipitation. It is a low to middle-level (family D1) stratiform cloud with some vertical extent that produces precipitation, developing cloud bases between the surface and 10000 ft (3000 m). This cloud typically forms from altostratus in the middle altitude range then subsides into the low altitude range during precipitation. Nimbostratus usually has a thickness of 2000 meters. In rare cases, Nimbostratus can be very thin and accompanied by a separate layer of altostratus divided by a cloudless layer. Though found worldwide, nimbostratus is found more commonly in the middle latitudes.

{Wikipedia}

related mobileGRIB variables: Total Cloud Cover, Precipitation

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Rain

Posted by on May 11, 2011 in phenomena | 1 comment

Rain

Berlin, Germany.

Rain is liquid precipitation, as opposed to non-liquid kinds of precipitation such as snow, hail and sleet. Rain requires the presence of a thick layer of the atmosphere to have temperatures above the melting point of water near and above the Earth’s surface. On Earth, it is the condensation of atmospheric water vapor into drops of water heavy enough to fall, often making it to the surface. Two processes, possibly acting together, can lead to air becoming saturated leading to rainfall: cooling the air or adding water vapor to the air. Virga is precipitation that begins falling to the earth but evaporates before reaching the surface; it is one of the ways air can become saturated. Precipitation forms via collision with other rain drops or ice crystals within a cloud. Rain drops range in size from oblate, pancake-like shapes for larger drops, to small spheres for smaller drops.

{Wikipedia, picture of elnuego}

related mobileGRIB variable: Precipitation

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