It is not always a continuous air stream, but may splinter into separate segments. Jet stream is usually thousands of kilometers long, a few hundred kilometers wide, and only a few kilometers thick. Jet streams are usually found at elevations between 10 and 15 km, even though they may occur at both higher and lower altitudes. Wind speeds in the center of jet stream often exceed 100 knots. Horizontal convergence occurs in the left rear and right front, while horizontal divergence occurs in the right rear and left front.
Subtropical jet is stronger and less variable with latitude than the polar jet.
Jet streams contribute the development and maintenance of cyclones. A jet stream typically progresses from west to east at a faster pace than does the west to east displacement of the troughs and ridges in the westerlies. The strongest divergence occurs when a jet maximum is on the eastern side of trough where a cyclone typically develops. It forms during dark polar winter. Low-level jet typically form at night above the temperature inversion.