CADIZ, April 4, 2014 (AFP) - A lengthy delay for rain on Thursday had already meant half the field had to complete their first rounds in the morning and the knock-on effect played further havoc with the schedule.
Warren, who had completed a level par 72 in the delayed first round, then went out and fired 67 to set the clubhouse target at five under par.
Horsey was four under par for his round with three holes remaining when play was halted for the day.
"My round didn't finish yesterday so I had to come back and play seven holes this morning and I played ok," said 33-year-old Warren.
"At the start of the second round I struggled a bit with concentration, but once I got it going I played really good -- my long game was excellent, short game was good. I think I got the best out of my round today.
"Today and yesterday's conditions were pretty similar, obviously without the rain. The wind is going to stay pretty strong and it's going to be tough for the guys playing this afternoon."
Horsey bogeyed the first two holes of his second round, but fought back with six birdies in ten holes from the fourth.
Chile's Felipe Aguilar was tied for third with Bradley Dredge and Adrian Otaegui on four under following a round of 69.
Leading second round scores in the weather-affected Cadiz Open on Friday (GBR/IRL unless stated, par 72):
Note: Play suspended due to darkness with 42 players to complete their second round.
139 - Marc Warren 72 67
140 - Felipe Aguilar (CHI) 71 69
142 - John Hahn (USA) 74 68
143 - Marco Crespi (ITA) 70 73, Mikael Lundberg (SWE) 71 72, Damien McGrane 74
69, Richie Ramsay 71 72, Lasse Jensen (DEN) 73 70, Matthew Nixon 72 71, Jack Doherty 69 74, Rhys Davies 72 71, Oliver Fisher 71 72, Scott Jamieson 71 72, Tjaart Van Der Walt (RSA) 70 73
144 - Thomas Norret (DEN) 73 71, Michael Jonzon (SWE) 74 70, Ricardo Santos (POR), 74 70, Jens Dantorp (SWE) 71 73, Matteo Delpodio (ITA) 71 73
145 - Andrew Johnston 73 72, Daniel Gaunt (AUS) 75 70, Oscar Stark (SWE) 74 71
146 - Joachim B Hansen (DEN) 77 69, Sihwan Kim (NOR) 70 76, Gary Lockerbie 76 70, An Byeong-Hun (KOR) 73 73
147 - Oliver Wilson 75 72, Maarten Lafeber (NED) 78 69, Lloyd Kennedy 75 72,
Adrien Bernadet (FRA) 76 71, Cyril Bouniol (FRA) 74 73, Victor Riu (FRA) 73 74, Simon Thornton 74 73, Alexander Levy (FRA) 72 75