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Forecast Graphics Descriptions
Supported by the Northwest Modeling Consortium

Soundings in depth

Atmospheric stability

To determine how stable regions of the atmosphere are atmospheric scientists look at the environmental air temperature lapse rate (the rate of change of the temperature with change in height) and compare it to dry and pseudoadiabats.

A step by step look into atmospheric stability can be found here.

Dry adiabat:

A line representing the dry adiabatic lapse rate defined as the temperature decrease (~10 C per 1000 meters OR ~5.5 F per 1000 feet) of a rising unsaturated air parcel. A sinking parcel of air will feel a temperature increase of the same magnitude.

Saturation mixing ratio

The mixing ratio (the mass of water vapor per unit mass of dry air (g/kg) ) of the atmosphere when it is saturated.

Pseudoadiabat

A line representing the moist adiabatic lapse rate defined as the temperature decrease (~6 C per 1000 meters) of a rising saturated air parcel.