Descriptions & Usage
Some descriptions provided by National Climatic Data Center (NCDC).
Hail Index A product designed to locate storms which have the potential to produce hail. Hail potential is labeled as either probable or positive. Probable means the storm is probably producing hail and positive means the storm is producing hail.
Mesocyclone This product is designed to display information regarding the existence and nature of rotations associated with thunderstorms. Numerical output includes azimuth, range, and height of the mesocyclone.
A non-dimensional number based on the following strength parameters: rotational velocity, shear, and GtG velocity difference (NSSL). This number indicates the strength of the rotation on a relative scale.
Weak to Minimal
Mesoscale Strength Index (MSI)
A non-dimensional value and is based on the vertical integration of the same three strength parameters that are incorporated into Rank calculations. The vertical integration is divided by the depth of the circulation and is weighted by density. This results in more of an emphasis on data from the lowest levels of the mesocyclone.
Additional reading on the Mesoscale Detection Algorithm can be found here:
Tornadic Vortex Signature A product which shows an intense gate to gate azimuthal shear associated with tornadic- scale rotation. It is depicted by a red triangle with numerical output of location and height.
A product which shows a plot of the past hours movement, current location, and forecast movement for the next hour or less for each identified thunderstorm cell. This product is used to determine reliable storm movement.