I was testing forecast building in anticipation of the summer severe
weather season, and uncovered what I consider a serious flaw regarding
thunderstorm attributes. It is possible there is a configuration way
around this but it is not obvious to me.
Part of our general procedures in the summer is to put thunderstorm
attributes in our weather grids in advance of severe weather
occurring, using the PotSevere grid. Testing the use of this grid
resulted in expected behavior with severe attributes (dmgW and lgA)
and T+ added to the weather grids in areas where the PotSevere grid
had 30% or more.
The problem occurred if we want to include non severe attributes (smA
and gustyW) for areas outside of the PotSevere 30% area. This is
something we would routinely do as storms in the northern high plains
intensify as they move away from the mountains. In the past we have
used the PotSevere 15-30% option to create an area for these
sub-severe attributes, and also allow for an area of general
thunderstorms (with no attributes). When I was testing this using
forecast builder, having a PotSevere grid with values ranging from
zero to 30+, PoPs and PotThunder for most of the area above 15%, and
selecting DmgW, gustyW, LgA, and SmA from the list of Thunderstorm
attributes, the result would be TRW- GW, SmA for everywhere with T,
and TRW+ GW, DmgW, LgA, SmA for everywhere that overlapped with the
PotSevere 30+.
Is there some way to fix this in the configuration or is the code
just a hold over from previous versions of FB? It would be nice to be
able to use this as we find it very helpful in messaging impacts for
our area.
