One of a forecaster's first thoughts when confronted with the 300/200 mb chart is the jet stream. The jet stream is a high velocity river of air that flows completely around the Earth at the mid-latitudes.. Below is a diagram showing the development of the polar jet and the wind pattern the PGF and Coriolis produce. Certain regions of jet.. Jet streams are winds that circle around the earth with poles as their centers. Narrow, concentrated bands. The stream of air is very narrow (50 -150 km across) and, the air in the stream is directed towards the axis of the stream making it very narrow. Meandering. When the temperature contrast is maximum, jet stream flows in near straight path.
:max_bytes(150000):strip_icc()/GettyImages-532103359-5b846575c9e77c007b87eea1.jpg "The Jet Stream An Overview in Geography")
A zonal jet stream is characterized by a flow nearly parallel to lines of latitude; in a meridional pattern, the jet stream shows highly amplified troughs and ridges. In a zonal flow, low pressure systems move quickly from west to east in the Northern hemisphere, while in a blocking situation, jet streams are highly meridional.. What is a Jet Stream? The Jet Stream is a geostrophic wind blowing horizontally through the upper layers of the troposphere, generally from west to east, at an altitude of 20,000 - 50,000 feet.; Jet Streams develop where air masses of differing temperatures meet. So, usually surface temperatures determine where the Jet Stream will form.