Severe hail from storm in Dodge City WFO

A severe thunderstorm had developed over the northwestern Dodge City, Kansas CWA Tuesday afternoon.  The NOAA/CIMSS ProbSevere values cycled between 45 and roughly 70% from 1925 until 1952 UTC; then radar observed reflectivity core rapidly increased, causing the ProbSevere values to correspondingly jump from 71% at 1952 UTC to 94% at 1956 UTC.  The jump in ProbSevere values as well as other features on radar (very strong storm top divergence and 3-body scatter spike (see post: http://goesrhwt.blogspot.com/2017/06/probsevere-compared-to-classic-radar.html)) warranted the DDC team to issue an experimental severe thunderstorm warning.  Shortly after the warning, 2.00" hail reports were received.

Figure 1. KDDC 0.5 degree reflectivity and ProbSevere contours valid 1926 - 1958 UTC 20 June 2017 for select times.

Another valuable discussion between myself and the forecaster was had where we examined the storm top divergence with this storm.  Strong storm-top divergence is something that often precedes a rapid intensification of a thunderstorm (and often severe reports).  Storm-top divergence is something a forecaster can quickly identify by analyzing all-tilts of base velocity data, but an automated storm-top divergence field is unavailable from the MRMS suite of products.  Such a field being made available in the MRMS suite could would be valuable for evaluation and possible inclusion into the ProbSevere model.

-Sieglaff