Using Weather Charts

There are many types of charts that meteorologists use to read and predict weather conditions. Current weather conditions are summarized in a ​ (a)   , a map that includes pressure patterns, fronts, wind direction, and speed.

• synoptic chart
• weather chart

​ (a)   are lines connecting two areas of similar pressure on the map. Isobars that are close together indicate a large difference in ​ (b)   , so the air will move quickly to correct the imbalance.

• weather chart
• Isobars
• pressure

• Isobars are lines connecting two areas of similar pressure on the map. Isobars that are close together indicate a large difference in pressure, so the air will move quickly to correct the imbalance. This results in strong winds. Isobars also tell the direction of the wind, because air moves in a​ (a)   direction around areas of high pressure and a counterclockwise direction around areas of low pressure in the Northern Hemisphere.

• weather chart
• clockwise

Areas of high pressure winds move in which direction?

• Clockwise

• Counterclockwise

Isobars that are closer together represent

• Stronger winds
• Increased humidity
• Stable weather conditions
• Weaker winds

Isobars that are closer together represent stronger winds because of large difference in

• cool air

• Increased humidity
• Stable weather conditions
• pressure

A ​ (a)   in air pressure causes wind to form, as air naturally moves from areas of high pressure to areas of low pressure, creating the movement we perceive as wind; the ​ (b)   the pressure difference, the stronger the wind will be.

• greater
• difference

• ​ (a)   , or the boundaries of an advancing mass of warm air, are signified by ​ (b)   lines with red semicircles in the direction the front is moving. Warm air follows a warm front.

• Warm fronts
• red

Cold fronts, or the boundaries of an advancing mass of ​ (a)   air, are signified by ​ (b)   lines with blue triangles in the direction the front is ​ (c)   . Cold air follows a cold front.

• cold
• blue
• moving

• ​ (a)   fronts, where warm fronts and cold fronts ​ (b)   , are signified by ​ (c)   lines with purple triangles and purple semicircles next to each other. This trapped air can result in patchy, light rain.

• Occluded
• intersect
• purple