Quote from: marcopete87
Temperature dropped from 25°C to 6°C that day (77°F to 42°F)
I can't see those links, so don't know what's there.
but can say 42F is too warm for graupel.. it really needs to be close to (or below) freezing for that to fall. (and within the cloud there must be a layer where water gets below freezing, but not enough that it freezes...until it encounters a falling partially-formed snowflake, when it does it freezes instantly to that, forming a somewhat-soft white ball). Interesting stuff, & kinda cool to see when it happens.
You no doubt had a coldfront come through that day with with a temperature drop like that.
I'm guessing you had a line of convective storms along the coldfront, and strong enough updraft within them for hail. Not uncommon at all for that to happen(atleast where I'm at). Storm doesn't have to be severe to produce small hail (half-inch or less)
(There's also something called 'ice-pellets' (or 'sleet') which look like tiny hail...but are formed differently than hail, and requires below freezing)