A year or two ago, I remember seeing a website which showed a map of the UK
with colour shading indicating where there was a risk of rotation /
vorticity / whatever which might lead to the formation of tornadoes. I have
a feeling that it was an experimental programme of some sort from a
university. Annoyingly, I haven't been able to find the site since then.
Does anyone know the one I mean, or something like it?

Thanks!