Uihlein finished the second round with a 4-under-par 68 for a 36-hole total of 6-under 138. He's one stroke ahead of Felipe Aguilar, who turned in a 1-under 71 in the second round.
Windy conditions, particularly for those having early Friday tee times, combined with tougher pin positions to affect scores.
Among those who played later were Raphael Jacquelin, who had the round of the day with a 6-under 66, and Rikard Karlberg, who shot 65 in the second round. That allowed them to jump into a tie with Aguilar for second.
Aguilar was tied with Morten Orum Madsen and Gary Stal for first after the first round. Madsen shot even-par 72 Friday and is 4-under for the tournament. Stal had seven bogeys in the second round and sagged to a 6-over 78, barely making the cut at 2-over after 36 holes.
Uihlein was even after seven holes Friday but got going with birdies at Nos. 8 and 9. He bogeyed the 10th hole but pulled into the lead with three birdies over the span of holes 14-17.
Senate Democrats to pull all-nighter on climate change
Scarlett Johansson steps out with fiance after pregnancy reveal