Weather map showing a stationary front
Windows to the Universe image by Lisa Gardiner
A stationary front forms when a cold front or warm front stops moving. This happens when two masses of air are pushing against each other but neither is powerful enough to move the other.
A stationary front may stay put for days. The front may start moving again, becoming either a cold or warm front. Or it may break apart.
Air temperature and wind can be different on opposite sides of a stationary front. The weather is often cloudy along a stationary front and rain or snow often falls, especially if the front is in an area of low atmospheric pressure.
On a weather map, a stationary front is shown as alternating red half circles and blue triangles like in the map at the left.
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