phenomena

Cyclonic Storm

Posted by on Sep 16, 2011 in phenomena | 5 comments

Cyclonic Storm

In meteorology, a cyclone is an area of closed, circular fluid motion rotating in the same direction as the Earth. This is usually characterized by inward spiraling winds that rotate counter clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere of the Earth. Most large-scale cyclonic circulations are centered on areas of low atmospheric pressure. The largest low-pressure systems are cold-core polar cyclones and extratropical cyclones which lie on the synoptic scale. Warm-core cyclones such as tropical cyclones, mesocyclones, and polar lows lie within the smaller mesoscale. Subtropical cyclones are of intermediate size. Upper level cyclones can exist without the presence of a surface low, and can pinch off from the base of the Tropical Upper Tropospheric Trough during the summer months in the Northern Hemisphere. Cyclones have also been seen on extraterrestrial planets, such as Mars and Neptune.

{Wikipedia}

related mobileGRIB variables: Pressure, Wind

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46° Celsius with 4% Humidity

Posted by on Jul 29, 2011 in phenomena | 9 comments

46° Celsius with 4% Humidity

near Awbari, Lybia.

A desert is a landscape or region that receives an extremely low amount of precipitation, less than enough to support growth of most plants. Deserts are defined as areas with an average annual precipitation of less than 250 millimetres (10 in) per year, or as areas where more water is lost by evapotranspiration than falls as precipitation. In the Köppen climate classification system, deserts are classed as BWh (hot desert) or BWk (temperate desert). In the Thornthwaite climate classification system, deserts would be classified as arid megathermal climates.

{Wikipedia}

related mobileGRIB variables: Humidity, Temperature

 

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Cirrus & Cirrostratus

Posted by on May 20, 2011 in phenomena | 28 comments

Cirrus & Cirrostratus

Groningen, Netherlands.

Cirrus clouds are the most common of the high clouds. They are composed of ice and consist of long, thin, wispy streamers. Cirrus clouds are usually white and predict fair weather. Sometimes called mares tails, they stream with the wind. By watching the movement of cirrus clouds you can tell from which direction weather is approaching. The appearance of cirrus clouds usually indicates that a change in weather will occur within 24 hours.

Cirrostratus are sheetlike, thin clouds that usually cover the entire sky. The sun or moon can shine through Cirrostratus clouds. Cirrostratus clouds usually come 12-24 hours before a rain or snow storm.

{boatsafe.com, picture of Bas Kers}

related mobileGRIB variables: Cloud Cover, Temperature, Precipitation, Wind arrows

 

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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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7 Beaufort wind

Posted by on May 11, 2011 in phenomena | 3 comments

7 Beaufort wind

Finistere, Bretagne, France.

The Beaufort Scale ( /ˈboʊfərt/) is an empirical measure for describing wind speed based mainly on observed sea conditions (on land it is categorised by the physical effects it has on vegetation and structures). Its full name is the Beaufort Wind Force Scale.

{Wikipedia, picture of Jérémie Janisson}

 

related mobileGRIB variable: Wind arrows

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Altocumulus Lenticularis

Posted by on May 11, 2011 in phenomena | 33 comments

Altocumulus Lenticularis

Otura, Granada.
Lenticular clouds are stationary lens-shaped clouds that form at high altitudes, normally aligned perpendicular to the wind direction. Lenticular clouds can be separated into altocumulus standing lenticularis (ACSL), stratocumulus standing lenticular (SCSL), and cirrocumulus standing lenticular (CCSL). Due to their shape, they are often mistaken for Unidentified Flying Objects (UFOs).
{Wikipedia, picture of nchazarra}
related mobileGRIB variables: Total Cloud Cover

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