Omega (Vertical Velocity)
Omega refers to vertical motion in the atmosphere, typically expressed in pressure coordinates (mb/s).
Negative omega values indicate rising air (lift), while positive values indicate sinking air (subsidence). Forecasters often examine layers such as 850–700 mb to identify where upward motion may support cloud formation and precipitation. Strong negative omega in this layer is commonly associated with developing showers or steady precipitation, especially when combined with sufficient moisture.
The term omega comes from the what’s called the omega equation which combines upper-level dynamics and lower-level temperature gradients to determine where air is forced to rise or sink.
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