Northampton and Derbyshire were frustrated by the weather at Wantage Road on Day Two, with only 29 overs possible, Northants moving to 66-0 having bowled the visitors out in the morning for 324, Shiv Thakor finished unbeaten on 83.
Derbyshire had resumed 275-8 and lost Luke Fletcher to the fifth ball of the day, Muhammed Azharullah removing his off stump, but Thakor and Andy Carter frustrated the hosts with a last wicket stand of 48.
However there was some concern for Carter after he was struck on the head by a Rory Kleinveldt bouncer, receiving lengthy treatment before being allowed to continue.
Once he did, he soon took Derbyshire past 300, hitting three fours in his 17, whilst Thakor took his overnight 60 to 83, but was denied a shot at a third first-class hundred when Carter top edged a hook off Azharullah to be caught at fine leg, Azharullah finishing with 4-95.
Northants had slipped to 6-4 in their first innings at Essex last week but there was no such alarms as Ben Duckett and Jake Libby made assured progress, despite the latter surviving a loud appeal for LBW off Nottinghamshire team-mate Fletcher from the first ball of the innings.
Duckett was soon into his stride, moving past 300 runs without being dismissed on home turf this season following his 282 not out against Sussex, and hit seven boundaries in reaching 36, whilst Libby was more circumspect in his 28.
The dark clouds loomed as the players resumed after lunch, and only eight balls of the afternoon were possible before the promised rain arrived and ensured no further play was possible.