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Weather PowerPoint Presentation

Weather

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Weather

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Presentation Transcript

  1. Weather

  2. We will Cover • Wind • Weather Forecast • Weather Chart • The passage of a Depression • Sample weather charts

  3. Why be aware of the Weather? • Avoid rough seas • Avoid disappointment • Decision making • Best diving

  4. Beaufort Wind Scale

  5. Weather Forecast • Definitions • Gale Warning • Severe Gale Warning • Storms • Imminent • Soon • Later

  6. Weather Forecast • Wind Strengths • Calm 0 • Light 1 to 2 • Moderate 4 • Fresh 5 • Strong 6 to 7 • Gale 8

  7. Weather Forecast • Visibility • Good • Moderate • Poor • Fog • Mist or Haze • Fair

  8. Weather Forecast • Obtained from: • Radio / TV • Newspaper • Met Office • VHF Radio • Web sites (surfing)

  9. Sea Area & Weather Stations

  10. Weather Chart • Air pressure at sea level - 1013 millibar • Variation is High or Low • Air will move from high to low = imbalance • Greater the imbalance, greater the wind • Isobar, line joining areas of equal pressure

  11. Anticyclone(Northern Hemisphere) • High Pressure • Pressure builds towards centre • Isobars far apart • Wind in clockwise direction • Settled, calm weather, fog • Frost in winter

  12. Cyclone(Northern Hemisphere) • Low Pressure • Pressure drops towards centre • Isobars close together • Wind anti-clockwise • Strong winds, unsettled • Rain

  13. A Front Warm front: • Overtaking warm air rises above a mass of cold air. • The gradient or boundary between the two masses is shallow. Cold Front: • Colder air pushes up under warmer air, gradient is much steeper

  14. A Front

  15. Passage of a Depression

  16. Sample Weather Chart

  17. Sample Weather Chart

  18. Summary • Wind • Weather Forecast • Weather Chart • The passage of a Depression • Sample weather charts

  19. Questions