Joakim Backstrom of Sweden, the 2005 champion, carded a bogey-free 68 for a share of third place with Andrew Marshall of England, Wade Ormsby of Australia and Frenchmen Charles-Edouard Russo and Michael Lorenzo-Vera.
Moriarty was among the first golfers to tee off in the morning and got off to a good start with a birdie on the first hole despite tough conditions.
"It can be very tricky when the wind gets up," Moriarty said. "The wind can be all over the place, so it's very easy to back off of some shots instead of taking them on. Today I just decided to pick my targets and swing at them, and it seemed to work out pretty well."
Wiegele caught up to Moriarty in the afternoon, making bogey on the second hole before recovering with six birdies over a nine-hole span.
"I was very pleased to shoot a 66," Wiegele said, "because the conditions were quite tough.
"The greens here are always quite tricky, and with the wind also blowing, it made for quite a tough day. So I couldn't have gone much lower than that."
Charlie Ford of England was three strokes off the lead in a tie for eighth place with Jordi Garcia of Spain, Alessandro Tadini of Italy, Mark Tullo of Chile and Michiel Bothma of South Africa.