synoptic charts

• Synoptic charts/weather maps show:

   weather conditions on the Earth at a specific point in time.
• weather conditions shown on synoptic chart include

  rainfall

  air pressure  

  wind direction and speed
• Air pressure is shown by fine black lines called:

  isobars

   
• What is air pressure measured in?

  Air pressure is measured in hectopascals (hPa).
• What hPa determines whether a weather is system is a high pressure or low pressure system?

  1013hPa
• Low air pressure systems have air pressures of.....

  measures below 1013hPa = low pressure system, (L)
• Low air pressure systems can bring weather such as 


  a cyclone or unsettled weather, strong winds, and often rain
• Is 1013 hPa is a low pressure air system?

  yes 1013 hPa or lower is considered a low air pressure system
• High air pressure systems are meseaured from

  
  

   1014hPa and above= a high pressure system.  

  
  

  bring settled weather

  
  

  denoted by H
• How do fronts from?? synoptic weather charts

  A front forms when two air masses with differing pressure (high and low) collide. 
• How can the direction of the wind in a front be determined.

  The direction that the semi circles or triangles point to is the direction that the wind is travelling in
• How are warm fronts represented on a synoptic chart

  A warm front is shown by a red line with red semi circles attached.
• How are cold fronts shown on a synoptic chart?

  Cold fronts are shown by a blue line with blue triangles attached.
• How do cold fronts develop?

  A cold front develops when a cold air mass pushes up under a warm air mass, forcing the warm air mass to rise and cool, forming rain.
• How do warm fronts develop

  A warm front is the result of a warm air mass replacing a cold air mass. Again, some of the warm air is forced to rise which causes it to cool, and brings heavy rain. Warm fronts move more slowly than cold fronts as it is harder for the warm air to push against the denser cold air.
• Stationary front 


  A stationary front is the boundary between two air masses that aren't moving.

  Neither mass is strong enough to push against the other, so a stationary front can remain over an area for days at a time.

  They are represented by an alternating warm and cold front symbol.
• Occluded fronts 


  An occluded front is a composite of two frontal systems that merge as a result of occlusion.

  Cold fronts move faster than warm fronts, so in the case of occlusion, a cold front will overtake a warm front, forcing the warm front to rise and sit ontop of the cold front. Again, this type of front brings rainfall.

  Occluded fronts are represented as a purple line with triangles and semi-circles.
• air pressure systems summary

  A low pressure system, (denoted by LL) measures below 1013hPa1013hPa and brings unsettled weather, and often rain.

  A high pressure system, (denoted by HH) measures above 1013hPa1013hPa and brings fine, settled weather.
• Troughs 


  Troughs are shown by thick black lines, and are a result of a sharp bend around a low.

  They represent particularly unstable areas that are associated with showers.
• Wind in pressure systems

  Wind moves from high pressure areas to low pressure areas, with direction of the wind depending on what hemisphere it is in.

  It also increases in speed within low pressure areas.