The Power Of Nature

[ZONE 51]

Welcome to the power of nature discussion!

Part 1 - THUNDERSTORMS

Every 2 weeks I will look at different types of powerful weather that affect the planet :

1 - Development

2 - What weather they bring

3 - A closer look at UK severe weather - please discuss this.

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Stages of Thunderstorm Development :

Cumulus Stage -

The initial stage of development is called the cumulus stage. During this stage warm, moist, and unstable air is lifted from the surface. In the case of an air mass thunderstorm, the uplift mechanism is convection. As the air ascends, it cools and upon reaching its dew point temperature begins to condense into a cumulus cloud. Near the end of this stage precipitation forms.

Mature Stage -

The second stage is the mature stage of development. During the mature stage warm, moist updrafts continue to feed the thunderstorm while cold downdrafts begin to form. The downdrafts are a product of the entrainment of cool, dry air into the cloud by the falling rain. As rain falls through the air it drags the cool, dry air that surrounds the cloud into it. As dry air comes in contact with cloud and rain droplets they evaporate cooling the cloud. The falling rain drags this cool air to the surface as a cold downdraft.

In severe thunderstorms the region of cold downdrafts is separate from that of warm updrafts feeding the storm. As the downdraft hits the surface it pushes out ahead of the storm. Sometimes you can feel the downdraft shortly before the thunderstorm reaches your location as a cool blast of air.

Dissipating Stage

The final stage is the dissipating stage when the thunderstorm dissolves away. By this point, the entrainment of cool air into the cloud helps stabilize the air. In the case of the air mass thunderstorm, the surface no longer provides enough convective uplift to continue fueling the storm. As a result, the warm updrafts have ceased and only the cool downdrafts are present. The downdrafts end as the rain ceases and soon the thunderstorm dissipates.

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The ground conditions can be light to extreme :

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http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/weather_systems/severe_weather_thunderstorms.html

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please discuss this topic and add photos and images..

Edited March 31, 2011 by Coast
To acknowledge the author of the information

[Mesoscale]

sometimes thunder can be earth shakingly loud and the reason is called ducting, when a warm front comes through there are two layers like a sandwich the bottom being the cold air and the top being the warm air in this type of setup we get what is know as elevated thunderstorms where the warm moist unstable air is being sucked up into the storm above the layer of cold air, sound travels faster through warm air so as the sound of the thunder approaches the cool air it gets compressed slowing the sound down it then can't excape from the cold air so its forced downwards towards the ground so instead of the thunder dispersing in every direction, its consentrated towards the ground. this is why thunder in those types of setups can be alot louder then a typical thunderstorm.

Heres a diagram i have put together to show what is happening,

The green area shows the sound wave of thunder getting compressed underneath the boundry.I forgot to add the cool air annotation, which is the area underneath the yellow line.

Edited March 31, 2011 by Mesoscale

[ZONE 51]

thunderstorm: hail-producing thunderstorm

Hail-producing thunderstorm

(Left) A hailstone can travel through much of the height of the storm during its development and may make multiple vertical loops. (Right) Most hailstones are formed by accretion around a nucleus (spherical embryo). Peculiarly shaped hailstones are generally the product of multiple stones fusing together.

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thunderstorm: thunderstorm structure

Structure of a thunderstorm

When the atmosphere becomes unstable enough to form large, powerful updrafts and downdrafts (as indicated by the red and blue arrows), a towering thundercloud is built up. At times the updrafts are strong enough to extend the top of the cloud into the tropopause, the boundary between the troposphere (or lowest layer of the atmosphere) and the stratosphere.

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Tornado

(Left) Tornadic thunderstorm

The rotating updraft that produces the tornado extends high into the main body of the cloud.

(Right) Anatomy of a tornado

Air feeds into the base of a tornado and meets the tornado's central downflow. These flows mix and spiral upward around the central axis. The tornado's diameter can be much greater than that of the visible condensation funnel. At times the tornado may be hidden by a shroud of debris lifted from the ground.

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Thunderstorm microburst

(Left) The air that forms the microburst is initially “dammed†aloft by the strength of the storm's updraft then cascades downward in a high-velocity, narrow column (less than 4 km, or 2.5 miles, in diameter). (Right, inset) Microbursts are very dangerous to aircraft and can create great damage on the ground. In the absence of observers, microburst damage can often be distinguished from that of a tornado by the presence of a “starburst†pattern of destruction radiating from a central point.

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Encyclopædia Britannica, Inc. B)

[Jane Louise]

Thanks for this both

I have only just seen this. Interesting to say the least