At 2120z SFX radar depcited a potentially severe thunderstorm located SW of Pocatello.  At this time, nearly 50 dBZ returns were observed in excess of 35kft.  The -20C level was approximately 17kft.  The MESH readout in ProbSevere showed 1.59″.  However, ProbHail was only 55%.  This appears to be a case where the ProbHail algorithm was reducing the probability based on the environment despite several aspects that support issuing in warning for severe hail.  A warning was issued for this storm at 2101z.