Tulsa-Claremore, OK Tornado

Most likely the strongest tornado of the day occurred just northeast of downtown Tulsa, Oklahoma, and moved east-northeastward toward Claremore and Justice, OK.

A strong GOES-derived normalized satellite growth rate, along with an increase in total flash rate from 22 to 35 flashes/min, increased the probability of severe to 84% at 22:42Z, in this high MUCAPE, high effective bulk shear environment, despite MRMS MESH only being 0.61 in. Fourteen minutes later (22:56Z), the probability increased to 95%, while MESH decreased to 0.56 in., and the flash rate increased to 84 fl/min. The probability generally stayed over 90% until the storm's demise. The first severe thunderstorm warning was issued at 23:35Z, about 40 min after the storm attained a >90% value from the ProbSevere model.

A tornadic debris ball signature was evident from KINX radar at 00:17Z, manifest in the base radar fields: a 'hook' signature in the reflectivity, strong velocity couplet, low correlation coefficient, and near zero or varying differential reflectivity; all coincident features are an indication that a tornado is creating and lifting debris. The storm also produced golfball-sized hail.

Future development of the ProbSevere model will investigate radar velocity products and dual-pol fields to give more accurate and hazard specific probabilities of severe (e.g., hail, wind, tornado).

KINX low-level scan ~00:17Z March 31, 2016. Images are from social media. The coincident signatures indicate a tornadic debris ball. Top-left: hook signature in horizontal reflectivity; top-right: strong inbound-outbound velocity couplet; bottom-left: a 'hole' of low correlation coefficient; bottom-right: near-zero differential reflectivity.