UK real time wind map covering Southern England.

The Jet Stream is a narrow band of fast flowing air at high altitudes. Usually the jet stream marks the boundary between the cold polar air to the north and warmer air to south.
The jet stream above the UK is called the Polar Jet Stream. The Jet Stream plays a large role when it comes to the weather across the UK, so from here you can view the latest jet stream forecast right out to 16 days in 3 hour timesteps.