My son is a 2020 and not yet committed, so take this fwiw:
I don’t think I’m disagreeing with Goosegg, but I’d say that while there were quite a few low to mid 80s pitchers, most were a a few ticks lower (more like 78-80). Pitchers in the low 80s (touching ~85+) with at least one off-speed pitch will attract some interest from D3s as rising seniors. (Younger guys, tall thin players who look like they have room to get stronger, and lefties can throw proportionately slower, of course.) As a rising Jr at HF and Showball, my 6’1” RHP son got a fair bit of email from D3s (and a few D1s) while sitting 81-84 mph. BUT, your son has to lay the foundation by getting in touch with coaches before the event and seeking them out while he is there
It is frustrating IMO that HF and Showball don’t publish velos or at least formally report them to Ps. Coaches will usually tell your son what velos they had him at if he asks. Also, a couple of the guys who caught my son at these showcases told him they heard the coaches (who sit behind home plate) discussing his gun readings and let my son know what they said his velo was. I’d ask my catcher to keep his ears open for me.
Finally, most HA schools want to see 3 years of HS grades before they seriously recruit. If your son is younger than a rising senior, don’t expect more than “we liked what we saw, keep us posted” (unless your kid is throwing 90+ and/or is 6’8”).