Weather

Types of Weather

Thunderstorms form when humid air lifts, cools, and condenses to form clouds. The cloud continues to grow higher until it forms a cumulonimbus cloud, and when the air becomes unstable, a thunderstorm forms inside. Tornadoes form when the wind in the storm changes irection and speed. This sudden change causes the clouds to rotate until it creates a narrow, spinning funnel.

Hail forms within an unstable air mass that produces large updraft speeds. Small ice particles that form in all thunderstorms collect rain or cloud water on them that form a shell that freezes. The updraft causes these hailstones to move and grow until they finally reach the ground. Wind is caused by air flowing from high to low pressure. Since Earth is rotating, though, the air flows mostly around these areas.

Floods are caused by heavy rainfall, runoff from deep snow, over-saturated or frozen soil, high rivers, urbanization, and ice jams in rivers. In contrast, droughts are caused by not receiving rain or snow over long periods of time.

Blizzards occur when a warm front collides with a cold front, creating a low pressure zone. When these clouds here fill with ice crystals and there is a lot of moisture in the air, major snow storms form. Hurricanes also form in low pressure zones, but they form over warm ocean waters. As water evaporates in this zone, winds simaltaneously begin to spiral inward to the center of the zone. The wind helps more water to evaporate and the storm grows in size and speed.

Sandstorms are caused by strong winds blowing over loose soil or sand and picks up this material, reducing visibility drastically. Sleet occurs ahead of a warm front in winter, usually between rain and snow. Rain in a warm layer falls into a cooler layer, freezing into sleet.

Pics 3-6:http://www.weather.com/news/year-in-pictures-20121219

http://upload.wikimedia.org/wikipedia/commons/7/75/Sandstorm.jpg

http://commons.wikimedia.org/wiki/File:Hail_RichmondHill.jpg

http://whyfiles.org/2012/what-is-sleet/

Pics 9-10:http://blogs.lowellsun.com/runningthevalley/?p=232

1950

Pics 1-2: http://photography.nationalgeographic.com/photography/photogalleries/nature-weather/