The ProbSevere model captured the development of severe weather in southern Colorado nicely during the evening of June 5. With one cell in particular, the first probability over 50% provided 20 min lead time to the first reported severe weather (1″ hail).

The algorithm started tracking the cell at 2136 UTC giving it an initial probability of 9% (to the first severe, Fig 1). At 2210 UTC, the algorithm had its first probability over 50% with a prob of 65%, indicating the cell was more likely than not to produce severe weather (Fig 2). The first severe weather of 1″ hail was reported with this storm 20 minutes later at 2230 UTC (Fig 3). The probability had maxed out at 85% at 2216 UTC.

– Bill Line, SPC/HWT Satellite Liaison