Today’s environment is ideal for all types of severe weather. Unsurprisingly, the ProbHail algorithm indicates high probabilities of hail with most of the storms. Here I’ll use dual-pol interrogation to investigate ProbHail performance and include a few additional observations.
Of particular note is the evolution of a storm object in the mind of the ProbHail algorithm. The algorithm seems to handle merging and splitting remarkably well for both the northern-most storm and the line of storms that results at the end of the loop in the SE part of the CWA. This performance in a highly-complex radar display is promising for more isolated storms. Let’s zoom in on the southeastern storm near Wellington:
The reflectivity signal in the hail core is not particularly anomalous (~50 dBZ), but ZDR near zero and reduced CC indicate high confidence in hail production at the surface. The ProbHail shows a 98% chance of hail in that storm. We would expect high confidence and this algorithm performs well. Baseball size hail was reported with this storm! -Atlanta Braves
Just after 20z on the eastern fringe of the LUB CWA, the KFDR radar indicated an area of very high inbound velocity. However, this data is in question as the elevated velocity occurred in an area of low Z and high SW, and likely not representative of the actual storm. This may have been caused by a side lobe. This had cascading affects with algorithms being tested which could not filter out the bad data. Low level az shear spiked to over 0.01 in a group of stationary pixels. This caused algorithms that ingest the az shear product to spike including ProbTor which increased to over 90%, as well as CPTI which showed lower end probabilities of a violent tornado in progress.
