Barry McCarthy's five-wicket haul saw Leinster Lightning almost restore parity on another rain-affected Championship day at North County.
The morning session began with Lightning dismissed for 131, with a further wicket apiece for Craig Young (4-26) and Graham Hume (3-34).
The Warriors reply started solidly with Ireland captain William Porterfield and Ross Allen (27) sharing an opening stand of 52 in 12 overs, before Allen fell lbw to Josh Little.
Aaron Gillespie joined Porterfield and the pair added a further 53 to put the Warriors in a seemingly dominant position at 105 for 1.
Enter stage left McCarthy who took four wickets in a devastating spell that saw the NW lose six wickets for 14 runs to slump to 119 for 7.
Simi Singh bowled 25 overs on the bounce to take 2 for 36, while debutant Will Smale was run out first ball - quite a contrast to his wonderful first day behind the stumps.
McCarthy broke a stand of 42 in 20 overs between Porterfield and Graham Hume (20), and Singh then dismissed Young in the following over.
Porterfield is still there unbeaten on 95, and will have his sights firmly fixed on securing his 12 first-class hundred in the company of number 11, Ryan MacBeth.
After the third session was lost to rain, unless there is another dramatic collapse on the third and final day, it seems a draw is once again inevitable in this rain-ravaged competition.
If the game is drawn, it opens the door for the Warriors and Knights to pip the Dubliners to the title in the final game at Bready in two weeks time.
Interpro Championship Day 2 Close of play score
Leinster Lightning 131 (45.4 overs; S Singh 29 ; C Young 4-26 G Hume 3-34)
North West Warriors 168/9 (66 overs; W Porterfield 95*, R Allen 27; B McCarthy 5-51, S Singh 2)-36