So are fast jet pilots relying on little more than Mark 1 eyeball and METARs etc when heading out on a sortie?
Yup!
Tornado F3 - one always tried to avoid CB, but I was hit by lightning twice in embedded CB, both at night doing PIs. Both times the CSAS tripped out but reset, and it did a fine job of minimising the bumps; no major snags apart from a couple of small entry/exit burn holes. Biggest problem was flying whilst blinded by the flash, it was very handy having the nav to do "talking AI" for about 30 seconds. It was not uncommon in Air Defence; one of the old hands gave me a few pointers for the second time, which worked a treat. I had the seat on lowest height with dark visor down and all the cockpit light on max when the big bumps started, then flipped up the visor just after the strike - snagless!
Whilst I was at Valley, a chap bit the tip of his tongue off in low level turbulence over Snowdonia; I'd chickened out around the same time after a 6g bump, so I think low level was worse for bumps. CSAS and sticking the wings a bit further back worked a treat on Tornado.