Understanding and monitoring weather conditions

Techniques and Fieldwork

Firstly it is important to understand the different weather instruments and their purpose. 

Primary and secondary methods of monitoring and understanding weather conditions

Primary:

  • Making observations and recording it in a weather diary 
  • Weather instruments – for more detail see post ‘using weather instruments – fieldwork’
  • Weather stations now use computer systems to record weather and keep organisations such as the Met Office involved through wireless and satellite connections.

Secondary:

  • Met Office website. This has synoptic charts to monitoring different weather conditions passing us e.g. fronts. It also keeps an archive of the weather so we can see weather patterns over a long course of time.
  • BBC website has some radar, satellite and surface pressure maps too which can help when trying to understand different weather conditions
  • People may write about the weather in blogs, websites and posts which allow us to measure weather conditions.
  • GIS – google earth, maps etc. This enables patterns of weather to be identified and measured of 4-10 days.
  • Media – watching news, documentaries etc

Can a winter anticyclone be classed as an extreme weather event?

What are the weather conditions shown in this map?

Firstly there is an winter anticyclone. The pressure is over 1000 (high pressure) and winds are blowing in a clockwise direction. There is also quite a large gap between isobars showing winds aren’t that high which fits in the model of a winter anticyclone. There will be hardly any clouds allowing the sun to shine through although the temperatures will still be low as there is a lack of clouds which allows heat to escape back into the atmosphere. We can see this through the symbols on the chart. The winter anticyclone has built up through cold and dry condition in Scandinavia and Eastern Europe. The Polar Continental air mass is the main one associated with this weather system.

There is also a cold front passing through North East England and Scotland. Traditionally, in anticyclonic conditions we do not see fronts forming but it just goes to show that real weather is much more complex than what the textbook says. In this front the cold air advances and force the warm air to rise sharply.

When the warm air rises quickly is condenses and causes a short rapid snap of heavy rain. Hence around the front we see symbols of rain.

What is an extreme weather event?

It is severe or unusual weather conditions e.g. hurricanes which cause severe impacts on the environment, people and economy.

So what are the risks with this condition?

  1. Firstly, temperatures can become extremely low bringing many health risks like hypothermia especially to children and the elderly.
  2. Many who suffer with breathing difficulties will probably have many problems. This is because first off the air is cold and dry and secondly there is a high risk or fog which is known to making breathing difficulties bigger.
  3. Fog is difficult to forecast in these situations do to cloud cover or the lack of it! This makes forecasting difficult and when extreme anticyclonic conditions are arising it is hard to forecast hence hard to act appropriately.
  4. Some extreme situations see heavy snow of ice falling. As we have seen in the last too months this can cause severe disruption. Many lives are lost, over a million people are not able to reach work and livestock are dying as they are not able to cope with these cold conditions.

 

Can a summer anticyclone be classed as an extreme weather event?

What are the weather conditions shown in this synoptic chart?

atmospheric-high-pressure.1
It is showing a summer anticyclone. We can see high pressure (pressure over 1000) and clockwise winds. Typically in this conditions the air mass is Tropical Continental – warm and dry winds from places like the Sahara. We can see no rain as in summer anticyclones we do not see much cloud formation as it is high pressure.There are light winds over England and Eastern Europe – we can see this through the knots and gap between the isobars.  However Scotland an Ireland have higher wind speeds and more cloud cover.

There is also an occluded front passing over this part of the UK – traditionally we do not see front in anticyclonic conditions- but just goes to show the weather isn’t as simple as the textbook suggests. The occluded front occluded front occurs where a warm front and a cold front meets. the means the amount of warm air that rises is larger than just a warm or cold front. This means that in that area there will be a down pour of torrential rain possibly.

occluded-front

What is an extreme weather event?


It is severe or unusual weather conditions e.g. hurricanes which causes severe impacts on the environment, economy and people.

So what are the risks associated with this weather system?

  1. As temperatures can become extremely high we will see many health risks of dehydration etc and this worst affects the elderly and the young.
  2. Water levels can become extremely low which means hydroelectric power and thermal power station may have to shut as the cooling process becomes impossible.This is dangerous because it is in a time when people will need Air conditioning in their homes.
  3. Once again there is a high risk of fog, which is hard to forecast, and this may cause breathing difficulties. Especially because pollution can get caught in sinking air causing smog – which is terrible for asthmatics.
  4. In extreme event ‘blocking highs’ can occur where the normal pattern of weather is diverted and we are stuck with the anticyclone for long periods of time.

Can a depression be classed as an extreme weather event?

Describe how the depression shown on this chart might produce extreme weather hazards.
 
What is an extreme weather event?
It is severe or unusual weather conditions e.g. hurricanes which cause severe impacts on the environment, people and economy.
What are the weather conditions shown in this map?

Firstly there is a depression. The pressure is below 1000mb (low pressure) and winds are blowing in an anti-clockwise direction. There is also quite a small gap between isobars showing winds are strong which fits in the model of a depression. There will be a large cloud cover as a depression is when warm air meets could air and this causes the warm air to cool resulting in precipitation. The depression has built up through cold and wet conditions in the Arctic Ocean. The Polar Maritime air mass is the main one associated with this weather system.
There is also a cold front passing through South East of England. Traditionally, in low pressure conditions we see occluded fronts forming on the actual land but even if it is close there will still be torrential rain on land. In this front the cold air advances and force the warm air to rise sharply. The result of a cold front is a rapid period of torrential rain.
So what are the risks with this condition?
    1. Firstly, temperatures can become extremely low bringing many health risks like hypothermia especially to children and the elderly.
    2. Torrential rainfall can lead to river flooding which especially with cold fronts lead to flash floods. The can cause many adverse effects  for example the Boscastle 2004 flash floods caused injuries, £2 million damage to buildings and roads and coastal pollution as debris and fuel from cars flowed out into the sea.
    3. In extreme situations could lead to a snowstorm or blizzard which as we saw in February 2009 causes disruptions and deaths.
    4. It could lead to high waves and surge may be destructive to the coast.
    5. In the case of flooding if sewage systems failed then they would be a risk of cholera and other disasters.