Shane Byrne moved to the top of the Cadwell Park timesheets during second free practice as inclement weather ensured lap times were well off those set in the morning.
The HM Plant Honda rider took advantage of the improving conditions towards the end of the session to claim the top time, four tenths ahead of Relentless Suzuki's Josh Brookes and MSS Colchester Kawasaki's Gary Mason.
With lap times some eight seconds down on FP1, Michael Rutter was fourth best on the Rapid Bathams Ducati, with Chris Walker rounding out the top five. Tommy Hill, who was fastest in the dry, could only manage sixth fastest on this occasion.
Elsewhere, there was drama for Ryuichi Kiyonari, who crashed at The Mountain, though the reigning champion was able to walk away unharmed.
Not every rider made it out onto track, with the likes of Tommy Bridewell and Jon Kirkham choosing to sit out the session.