Mid-week summary

In the next Step you’ll be able to consolidate what you’ve learnt so far by reading a weather map. Let’s first summarise what has been covered.

  • Weather systems act to even out the pole to equator temperature gradient.
  • Winds are trying to even out the pressure gradient.
  • The wind blows around the depression in an anticlockwise direction in the Northern Hemisphere, following the pressure contours.
  • The three dimensional processes are key – they lead to cloud, rain and energy being released.

The damage caused by a depression is governed by:

  • The pressure difference, which in turn determines the wind speed.
  • The time of the year, if the trees are in leaf, they offer more resistance to the wind and are more likely to be blown over.
  • The preceding weather – if the ground is already waterlogged, flooding is much more likely. Also, trees and walls are more likely to collapse if on waterlogged ground.
  • The path of the storm, and whether it passes over land or sea, or highly populated or less developed areas.
  • The state of the tide – coastal flooding is much more likely if a storm coincides with a particularly high tide.
  • Forecast accuracy – if people have notice to avoid travelling, keep high sided vehicles off roads etc. then the damage and disruption can be reduced.

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This article is from the free online course:

Come Rain or Shine: Understanding the Weather

University of Reading