weather [winds] [appearing pictures]

• 1. clouds
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• 2. supercell storm clouds
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• 3. hurricane seen from space eye visible
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• 4. hurricane cross section
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• 5. tornado [1] useful as it shows touching ground
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• 6. tornado [2]
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• 7. tornado [3]
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• 8. tornado [4] useful as it shows touching ground
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• 9. thunderstorm formation [1] [labelled]
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• 10. thunderstorm formation [2] [unlabelled]
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• 11. thunderstorm formation [3] [unlabelled] [stage 1] [cumulus]
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• 12. thunderstorm formation [4] [unlabelled] [stage 2] [mature]
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• 13. thunderstorm formation [5] [unlabelled] [stage 3] [disapating]
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• 14. wind force [title]
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• 15. wind force [1] [unlabelled] [calm]
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• 16. wind force [2] [unlabelled] [gentle]
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• 17. wind force [3] [unlabelled] [moderate]
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• 18. wind force [4] [unlabelled] [strong]
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• 19. wind force [5] [unlabelled] [gale]
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• 20. wind force [1] [labelled] [calm]
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• 21. wind force [2] [labelled] [gentle]
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• 22. wind force [3] [labelled] [moderate]
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• 23. wind force [4] [labelled] [strong]
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• 24. wind force [5] [labelled] [gale]
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• 25. isobar low and high
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• 26. isobar high to low
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• 27. isobar map
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• 28. isobar map with front
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• 29. barometer
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• 30. cyclones and anticyclones [labelled]
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• 31. high and low pressure [1]
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• 32. high and low pressure [2]
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• 33. high and low pressure [3]
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• 34. high and low pressure [4]
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• 35. high and low pressure [5]
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• 36. rotating Earth showing wind patterns
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• 37. wind patterns on Earth
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• 38. wind circulation
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• 39. anticyclone high pressure diverging air
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• 40. cyclone low pressure converging air
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• 41. high pressure
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• 42. low pressure
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• 43. anticyclone [labelled]
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• 44. cyclone [labelled]
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• 45. diverging winds
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• 46. converging winds
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• 47. El Nino
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• 48. La Nina
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• NOTES
• 1. Wind is the movement of air around the earth.
• 2. The wind moves from areas of high pressure to low pressure.
• 3. The direction given for the wind refers to the direction from which it comes.
• 4. For example, a westerly wind is blowing from the west towards the east.
• 5. Measurements of wind strength are made at 10 metres above the ground.
• 6. A specified height has to be used so that all the measurements
• 6a. taken across the world can be compared.
• 7. In the UK winds are measured in knots (nautical miles per hour).
• 8. However, forecast winds are often given in miles per hour.
• 9. or in terms of the Beaufort Scale.
• 10. There can be rapid variations in the speed of the wind
• 10a. these are referred to as gusts.
• 11. Gusts are higher inland than over the sea or windward coasts,
• 12. although the mean wind speeds tend to be lower inland.
• 13. Typically, gusts can be 60% higher than the mean speed,
• 14. although in the middle of cities this can reach 100%.
• 15. Northerly winds tend to be gustier than southerly ones.
• 16. Northerly winds tend to bring colder air from polar regions .
• 17. to the British Isles.
• 18. As cold polar air moves southwards over a warm sea,
• 18a. the heating of the air by the sea causes cumulus clouds to form.
• 19. These clouds may grow sufficiently for showers to develop
• 20. and, consequently, winds from the north-west, north or north-east
• 20a. usually bring cold, showery weather to the British Isles.
• 21. Southwesterly wind bring warmer air from the tropics,
• 21a. which is cooled as it moves northwards over a cooling sea.
• 22. Sometimes the cooling is sufficient for sea fog
• 22a. or a thin layer of stratus to form.
• 23. The cloud can become thick enough for drizzle,
• 23a. especially on windward coasts and over high ground.
• 24. In general, the weather is strongly influenced by the wind direction,
• 25. so information about the wind provides an indication
• 26. of the type of weather likely to be experienced.
• 27. However, southerly winds can sometimes bring hot, thundery weather.
• 28. Easterly winds in winter bring very cold air to the British Isles.
• 29. In general, winds from the west or
• 30. southwest are associated with overcast, wet weather.
• 31. Winds from the south and southeast mainly occur
• 32. in summer and these bring warm, dry weather.
• 33. The characteristics and path of the air determine whether it is cloudy .
• 34. (with perhaps rain, sleet or snow) or fine and sunny
• 35. In summer, an easterly wind will mean it is cool on the east coast
• 36. but warm elsewhere, usually with clear skies.
• 37. Thunderstorms are one of the most dangerous types of weather.
• 38. Over 40,000 thunderstorms occur throughout the world each day.
• 39. Thunderstorms form when very warm, moist air rises into cold air.
• 40. As this humid air rises, water vapour condenses,
• 41. forming huge cumulonimbus clouds.
• 42. There are two main types of thunderstorms: ordinary and severe.
• 43. Ordinary thunderstorms are the common summer storm
• 44. and usually last about one hour.
• 45.
• 46.
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• 50.

The precipitation associated with these storms includes rain and occasionally small hail. With ordinary thunderstorms, cumulonimbus clouds can grow up to 12 kilometers high. Severe thunderstorms are very dangerous. They are capable of producing baseball-sized hail, strong winds, intense rain, flash floods, and tornadoes. Severe thunderstorms can last several hours and can grow 18 kilometers high. Several phenomena are associated with severe thunderstorms, including gust fronts, microbursts, supercell thunderstorms, and the squall lines. Tornadoes form from severe thunderstorms. They have a very high energy density which means that they affect a small area but are very destructive to that area. They also don't last very long which makes it hard to learn about them. Since they're hard to study, they're also hard to forecast. People know even less about tornadoes, which is why there are a lot of different myths that aren't true. Tornadoes can occur anywhere in the world. About 75% of them happen in the United States, most in an area know as Tornado Alley. There are also some other interesting facts about tornadoes. People who are interested in tornadoes sometimes become trained tornado spotters for their community. Others chase tornadoes, either to research these incredible storms, or to photograph them. After a tornado touches down, scientists try and figure out how strong it was by using the Enhanced Fujita Tornado Scale. As a strong hurricane heads towards the coast, people prepare - boarding up houses, packing the car, and evacuating. These storms can spell disaster for people in hurricane prone areas, so they are taken very seriously. They are the most powerful of all weather systems and they are huge - an average of 340 miles across. Hurricanes form in the tropics over warm ocean water and die down when they move over land or out of the tropics. These storms are called hurricanes in the Atlantic and typhoons or tropical cyclones in other areas of the world. In the Northern Hemisphere the storms rotate counterclockwise and in the Southern Hemisphere they rotate clockwise because of the Coriolis Effect. At the center of the rotating storm is a small area of calm weather and clear skies called the eye. Hurricane damage in coastal areas is often due to storm surge, which floods coastal areas. Strong waves and wind also batter coastal areas. Hurricanes also cause a tremendous amount of rain. Not all storms are the same. Large and strong storms cause much more damage than small storms. In the Atlantic and Eastern Pacific, the Saffir-Simpson Hurricane Scale is used to describe the size of a hurricane. As hurricanes move, scientists try to forecast where and when the storm will reach land in order to warn people. Hurricanes are tracked over large distances with weather satellites. Computer models that take into account factors of the storm and the atmosphere are used to predict where the storm will go. Since 1953 each hurricane has been given a name to help warn people that a storm was on its way. Hurricanes usually happen at a particular time of year called hurricane season. The timing of hurricane season is different in different regions of the world. In the North Atlantic, hurricane season is from June 1st to November 30th each year.

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