The Jetstream is currently weak and split, lying to both the north and south of the UK. However, it is set to strengthen into a single jet over the next few days and lie across the UK. This change will bring more unsettled weather for all as we head into the weekend, but it will be less cold as a result. | Met Office

This animated JET STREAM FORECAST shows how the northern and southern streams are to combine or "phase" to generate the vertical motions in the atmosphere which will drop Central U.S. barometric pressures precipitously---generating wind and significant precip in the process. The color scheme highlight wind velocities. Note how a powerful phased "wind max" develops aloft over the Central U.S. in this animated forecast. It's that wind max that is to drive rapid intensification of the winter storm

What exactly is a jet stream and how does it affect the weather? Learn this and more in the latest lesson from SciJinks, brought to you by NOAA's GOES-R series of satellites! Full lesson: go.usa.gov/xpJFj | NOAA Satellite and Information Service