Today was the first day of Week 2 for the Satellite HWT Experiment.  One of the main applications we are looking at this week is the new ProbSevere Model version 3.  We are able to compare this version to the one currently in use (version 2).  This is the version most operational forecasters are familiar with, and that is available in AWIPS2 and GR2 Analyst.  

The target today was convection occurring in the Shreveport, LA CWA this afternoon.  A QLCS was moving across the region from west to east, as shown below.  The reflectivity was not especially impressive, but velocity scans occasionally showed some stronger winds.

The image shows MRMS Vertically Integrated Ice (VII) on the left, a parameter many forecasters are familiar with and may use as perhaps a “sanity check” to see if a cell may be trending towards strong or severe.  On the right is a screenshot of the Shreveport radar (KSHV) at the 0.3 degree reflectivity slice.  Overlaid is the ProbSevere Model with ProbSevere2 and ProbSevere3 parameters both listed for comparison.  

As you can see there are a few areas of concern.  A quick glance at VII indicates there may be some strong updrafts capable of hail over the area of convection over southeastern Caddo County in northwestern Louisiana.  Looking at the output for ProbSevere2 in this same area, there is a 43% chance for hail in this area, and a 14% chance for hail according to ProbSevere3.  The new and not yet operationally available ProbSevere3 uses a newer, more highly-skilled algorithm that should theoretically better match with ground truth.  

During this time there were no hail reports in SPC’s database, severe or otherwise.  There were some areas of surface based CIN noted, and this may have suppressed stronger updrafts and thus large hail. So in this case, it appears that the newer version of ProbSevere was correct about hail not being severe.  

-Dana Scully