ZONAL FLOW

Zonal flow is a meteorological term meaning that the general flow pattern is west to east along the earth's latitude lines (as opposed to meridional flow).  Extratropical cyclones in this environment tend to be weaker, moving faster and producing relatively little impact on local weather.
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Large-scale atmospheric flow in which the east-west component (i.e., latitudinal) is dominant. The accompanying meridional (north-south) component often is weaker than normal. Compare with meridional flow.