I was wondering if anyone could explain to me the metric "correlation coefficient" as it is used in determining when a funnel cloud becomes a tornado. What I have read so far about this metric confuses me in how the metric is used. My background is as a research psychologist and "correlation coefficient" is used very differently in the social sciences.

I am continuing my search to learn more and I wanted to bounce this around in this forum to see if I could gain some additional insight to how it is used and if anyone has worked with data related to determining the thresholds with correlation coefficients. I would be really interested in discussing this.