Isobars are lines on a weather map that connect places with equal air pressure. They indicate wind patterns and can be used to predict weather. Isobars that are closely spaced indicate high wind speeds, while widely spaced isobars mean gentle winds. Low pressure systems are associated with clouds and precipitation, while high pressure typically brings fair weather.

1. Isobars
• They are lines that connect places with equal air pressure .
•Example :
On the map isobars marked: 1004 represents an area of high pressure
976 represents an area of low pressure

2. Map showing ISOBARS
Look at the map ,notice the series of circles in the east .This pattern is a low pressure
system(L) ,or low .Isobar readings decrease toward the center of a low pressure system.
The map shows another set of isobars in the west . This pattern is a high- pressure
system (H),or high. The center of this system has high has higher air pressure than the
surrounding area .

3. Importance of ISOBARS
• Isobars give scientists an idea of wind speed .
• Air moves fastest where pressure differences are greatest .
• Isobars spaced closely together show a large change in pressure over a
small area .
They indicate that wind speeds will be high.
• Widely spaced isobars indicate gentle wind .

4. Air pressure and weather
•Different types of weather develop in highs than in lows.
•In general , areas of high pressure have fair weather .
•Cumulus clouds might be present , but generally little or no
rain falls .
•A low-pressure area usually has clouds and precipitation.
•Storms and rain often follow a drop in air pressure .
•When the barometer reading drops suddenly ,it is likely that
precipitation will fall .