Helicity is a property of moving air, representing the potential for flow that follows a corkscrew pattern. The helicity value is computed from the vertical wind profile of the lower atmosphere. It is used to forecast the formation of mesocyclones. The following helicity values are considered of consequence at at NASP:

150 =The approximate threshold for supercell development

150 299 = Weak Tornadoes (F0 and F1) possible

300 - 449 =Strong tornadoes (F2 and F3) possible

>450 =Violent tornadoes (F4 and F5) possible

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