Davis Stability Index (DSI)

Is a measure of temperature difference between the forecasted maximum temperature (degrees C) and the 850mb temperature (degrees C). The resulting temperature difference is then used to determine the stability of the atmosphere. This index was developed in the southeast United States and is most commonly used in the Carolinas. The formula for the Davis Statbility Index is as follows:

Davis Stability Index (DSI) = MaxT(C) - 850mb Temp(C)

Cat 1 (difference <10C) Stable
Cat 2 (difference 10-14C) Conditionally Unstable
Cat 3 (difference 15-17C) Unstable
Cat 4 (difference >17C) Absolutely Unstable