Air temperature at 2 metres
40C>
<-40C
-20
0
20
1
The polar vortex is an area of low pressure and extremely cold air that swirls over the Arctic
2
Disturbances in the jet-stream and the intrusion of warmer air can disturb this polar vortex sending Arctic air south into middle latitudes
Extremely
cold air
masses
plunge
south
Warmer
than usual
air over
Arctic
3
Masses of extremely cold air have plunged towards the interior of North America and at least 90 million Americans could experience temperatures at or below zero (-18C)
<-40C
-20
0
20
40C>
Air temperature at 2 metres
1
The polar vortex is an area of low pressure and extremely cold air that swirls over the Arctic
2
Disturbances in the jet-stream and the intrusion of warmer air can disturb this polar vortex sending Arctic air south into middle latitudes
Warmer than
usual air
over Arctic
Extremely cold
air masses
plunge south
3
Masses of extremely
cold air have plunged towards the interior of North America and at least 90 million Americans could experience temperatures at or below zero (-18C)