The K Index



The K Index is the measure of thunderstorm potential based on the vertical temperature lapse rate, the moisture content of the lower atmosphere and the vertical extent of the moist layer.

As NASP, the following K Index values are guidelines:

    20 25 = Isolated thunderstorms

    26 30 = Widely scattered thunderstorms

    31 - 35 = Scattered thunderstorms

    35 and > = Numerous thunderstorms

Concept Mapping Toolkit
Insitute for Human and Machine Cognition
The University of West Florida