James Sales hit a determined 70 but Northamptonshire 2XI were bowled out for 237 in difficult batting conditions at Edgbaston Community Sports Ground.
Northamptonshire 2XI won the toss and elected to bat, with Hassan Azad and Harry Gouldstone opening the batting.
Unfortunately, most of the first hour of the game was hindered by the rain, with only 20 overs being bowled by lunch.
Northamptonshire finished the morning session on 74/1 with Hassan Azad unbeaten on 24 and Rohan Mehmi on 14.
Harry Gouldstone was the only wicket to fall as he was dismissed for 30, hitting seven 4s before being trapped LBW by Manraj Johal in the 12th over, ending the 46 run opening partnership with Azad.
After lunch, Azad and Mehmi were forming a solid partnership for the 2XI but in the 26th over, Azad retired not out after being struck on the helmet, bringing James Sales to the crease.
The pair scored at a steady rate, bringing up their 50 partnership in the 48th over.
However just before tea, Mehmi was trapped LBW on 45 by Y Singh and Gus Miller was bowled by Singh, leaving Northamptonshire 2XI 149/3 by the end of the afternoon session.
The 2XI scored 88 runs after tea, but Warwickshire took 6 wickets to reduce Northamptonshire to 237 all out as Hassan Azad was unable to return to the crease.
The last wicket to fall was James Sales, who posted a patient and impressive 70 off 158 deliveries, including six 4s and one maximum.
Y Singh and Manraj Johal were the pick of the Warwickshire bowlers, taking four and three wickets respectively as proceedings were brought to a close after the dismissal of Sales, with Warwickshire heading in to bat for their first innings on Day 2.