Synoptic Charts Tutorial

synoptic charts: learn - test - check

Synoptic = summary of current situation.

Synoptic Chart Key:

A = Isobar

B = Warm Front

C = Cold Front

D = Pressure in Millibars

E = Occluded Front

F = Trough

G = Low Pressure System

H = High Pressure System


What do isobars tell us?

Wind Speed:

  • Closely spaced Isobars indicate large pressure changes causing wind speeds to increase. 

Wind Direction:

In the Northern Hemisphere Winds will:

  • Winds will blow anti-clockwise around an area of Low Pressure (Cyclone)
  • Winds will blow clockwise around an area of High Pressure (Anti-Cyclone)


  • Lines of equal atmospheric pressure

Wind Direction (Northern Hemisphere):

Winds will blow anti-clockwise around an area of Low Pressure (Cyclone)

Winds will blow clockwise around an area of High Pressure (Anti-Cyclone)

Warm Front:

A warm front occurs when a warm air mass slides over a cold air mass.

These are formed when warm air rises over a mass of cold air. As the air lifts it cools, expands and condenses the water vapour as wide flat clouds. Warm fronts usually bring low and thick cloud & drizzle. 


Cold Front:

Usually associated with Depressions. A cold front is a transition zone where a cold air mass is replacing a warmer air mass. The cold air is following the warm air and gradually moves underneath the warmer air. 

Commonly, when the cold front is passing, winds become gusty; there is a sudden drop in temperature, and heavy rain, sometimes with  hail, thunder, and lightning. Lifted warm air ahead of the front produces cumulusor cumulonimbus clouds and thunderstorms. 


Occluded Front:

This occurs where two different air masses meet. A band of thick cloud is created when the cold air catches up with the warm front. 

Occluded fronts usually bring sudden downpours of heavy rain.


A trough is an elongated (extended) region of relatively low atmospheric pressure, often associated with fronts. Most troughs bring clouds, showers, and a wind shift, particularly following the passage of the trough. This results from convergence or "squeezing" which forces lifting of moist air behind the trough line.

Test yourself:

Synoptic Chart Quiz Sheet.pdf
Adobe Acrobat Document 254.6 KB

check yourself:

Synoptic Chart Quiz Answers.pdf
Adobe Acrobat Document 256.6 KB

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