Opening MotoGP practice for the Spanish MotoGP at Jerez ended with just eight riders setting a lap time due to unpredictable rain showers.

A light shower descended just before the start of the 45-minute session. The off/on drizzle then caused 'in-between''track conditions for the majority of the session, before a heavy downpour in the final five minutes.

That at least meant full wet settings could be used with confidence and caused a few more riders to venture out.

But the timesheets were still led by Avintia's Ivan Silva (who has one part carbon fibre Inmotec frame alongside his FTR bike this weekend) thanks to a lap time in the earlier damp conditions.

Home rider Silva was credited with a lap time 5.967sec ahead of LCR Honda rookie Stefan Bradl, whose time came at the end of the session. Silva was ten seconds from dry record pace.

Last year's Spanish Grand Prix was also held in the wet and the mixed conditions are expected to continue for the remainder of the weekend.

Second free practice takes place this afternoon.

Friday practice (1):

1. Silva
2. Bradl
3. de Puniet
4. Bautista
5. Pasini
6. Pirro
7. Hernandez
8. Edwards