Keyword, formed… Lightning can start being seen rather early in these types of rapidly building thunderstorms before they get real big. Some small thunderstorms can produce lightning before the tops reach 12,000 feet but you’re still going to notice a built up cloud system not just scattered cumulus or lightning coming out of practically clear air. Lightning can come out of nimbostratus and altostratus though. Perhaps asobo will refine how the sim might handle rendering of building storms or (BLDUP). Perhaps that is what is happening in the sim where metar is reporting developing storms and where thunderhead (THD) are non metar but instead TAF? Graphical forecasting supersedes area forecasting now which would be awesome to be able to see reflected in the sim in real time.
Surely indeed if in fact there is a build up of a thunderstorm/s. Does lightning come out of broken or scattered cumulus clouds there in Florida before they become cumulonimbus? What do you mean by constant lightning?