What is the Jet Stream?

video preview image

What is the jet stream and how does it effect the weather?                                                                                                                                                    Burkus Kaizer                                                                                                                                                                                                                                                  Griffen Creek

The jet stream is a fast moving current of air in the higher levels of our atmosphere. It separates the warmer air in the tropics from the cooler air towards the poles. In these higher levels of the atmosphere where the jet stream is present, temperatures are very cold. But near the surface, temperatures can vary, depending on the season.

In the winter time, when surface temperatures are much colder than summer, the temperature different between the low levels and higher levels of the atmosphere are of great difference. Meteorologists call this a temperature gradient. The stronger the temperature gradient, the stronger the jet stream. This is the same for surface temperatures. When the gradient is high between the southern and northern tier of the United States, for instance very cold across the North and very warm across the South, the jet stream is also very strong or fast moving.

In addition, the Earth is always rotating. This rotation, as well as friction due to land and water surfaces, leads to curvatures in the jet stream. In areas where the jet stream moves southward, bringing cooler temperatures further south, an area of low pressure can be found. Consequently, in areas where the jet stream pushes north, bringing warmer temperatures northward, areas of high pressure can typically be found. The specific locations of the jet stream, can enhance precipitation and has a key role in the type of weather we see on a daily basis.