In this case, the prob severe tool seemed very slow to react to this intensifying tool.  I would have warned about 2 to 3 scans before this picture.  In this particular picture, it shows a solid hail core around 25,000 feet AGL which was there for one to two scans prior.  However, the MESH is only indicating 0.71 inch hail, which is quite underdone in my opinion.  This low MESH is driving a low severe probability, 41% in this case.  In this case, the probsevere tool would likely have missed the first reports of severe hail due to a seemingly slow response time in the MESH product, which gave falsely low values in the probsevere tool.