Hail Storm in Daytona Beach
Accumulating hail fell in Daytona Beach FL (Link) on 6 March 2021 in association with a front over the Florida peninsula. Preliminary storm reports from SPC (link) show reports of 1″ to 1.75″ hail. (The region was under a general thunderstorm outlook from SPC: link). The animation above shows the Convection RGB from 1431 through 1701 UTC on 6 March, bracketing the hail event over Daytona Beach near 1600 UTC. A strong white/yellow signal develops in a cell over Volusia County (Dayton Beach is within Volusia County) around 1545 UTC. This is the cell that deposits the hail.
ProbHail values for this event (from this website) were small, at less than 10%. The value of ProbSevere here could be in identifying the cell responsible for the Hail, and showing values for the radar object that exceed others nearby; that is, providing guidance as to which radar cell to interrogate most often. The image above shows ProbSevere at 1535, just before a Severe Thunderstorm Warning was issued. The image below shows ProbSevere at 1600 UTC, just after the Special Marine Warning was issued (and while the Severe Thunderstorm warning was still in effect).
The time series plot for the radar object that produced the hail is shown below. Note that ProbHail (and lightning) increased (marginally) before the hail events (reported between 1535 and 1615 UTC) before collapsing.
There are several features in the visible imagery, below, that might be affecting the thunderstorm producing the hail. An east-west boundary is moving down the Atlantic coastline, passing through Daytona Beach around 1551 UTC. A very strong reflective signal becomes apparent after 1541 UTC as well (link): the convective cell has penetrated through the cirrus shield in the region.
This was a challenging forecast in a marginal environment.