Back in June 2015, I posted two reference guides that could be useful when interrogating storms on radar. The first was related to tornado intensity estimation in real-time, and the second was related to analyzing tropical cyclone tornadoes. After posting these, I worked with some people with the Warning Decision Training Division (WDTD) to fine tune some of the numbers on the first reference guide. The tropical cyclone tornado reference guide remains unaltered from the initial version. You can find the initial post by clicking here.
Before I share the updated reference guide, let me reiterate these words of caution that I included with the original post. Please read them before using.
Remember, this is a reference guide with some rules of thumb, so the numbers listed aren’t intended to be taken literally in every situation. For example, a 60 knot maximum rotational velocity with a tornadic supercell doesn’t guarantee a strong tornado, but it does indicate you are in a situation where a strong tornado would be more likely. As one of the tips points out, that would be especially true if the tornado was moving fast, in a very favorable environment for strong tornadoes, or the signature was sampled poorly. The “overlap” ranges listed on the chart in the bottom left corner do not encompass all cases of overlap. Therefore, the general principle is that as your rotational velocity and/or tornadic debris signature height increases, so too does the likelihood of a more intense tornado on average.