With lead time of ~30 mins to a strongly tornadic event, Az/DivShear were exceeding threshold values, despite rather meager rotational convergence (mostly purely convergent) from V/SRM analysis (see above). This time (~1920 UTC) also corresponds with a large jump (~20 to ~50%) in TORP probability.  At minimum, the PHI products helped as a situational awareness tool to an evolving threat (rapid increase towards rotational convergence and significant tor-gen).

This is in strong contrast to a storm that later impacted portions of Allendale County, South Carolina about an hour later. A rather deep mesocyclone and at least weak (~15-20 knot VROT at 0.3-degree) rationally convergent signature was noted. However, TORP remained <30-40%. Will closely monitor how this tracks across a continuum of cases the rest of the week.   -QLCS