Lees hammered five sixes and 16 fours in a 125-ball innings before retiring out as Yorkshire scored 409-5 from their 50 overs.
Captain Gary Ballance struck an unbeaten 92 from 59 balls with 12 fours, while Adam Lyth chipped in with 68.
Lees and Lyth shared 137 for the first-wicket inside 17 overs before Ballance was at the centre of a fierce final onslaught, with 104 coming from the last 10 overs.
In reply, UAE Blues crashed to 72 all-out to lose by 337 runs, off-spinner Azeem Rafiq capturing 4-10.
Yorkshire’s next match is their opening first-class game of the season against Leeds-Bradford MCCU at Headingley, starting on Sunday.
Northants have appointed ex-England batsman James Taylor as a 50-over coaching consultant.
Taylor, 27, retired with a heart condition last April after seven Test and 27 one-day international appearances.
“It’s great to see his desire to still be involved with the game,” said Northants’ head coach David Ripley.
“James has a fantastic 50-over record, averaging over 50 which is obviously outstanding.
“I believe he can offer good advice and relay his one-day cricket experiences on to our batsmen.”
David Sales, the former Northants’ captain, has taken on a part-time coaching role at the club.
“David has been working part time with the batters since January, focusing on improving more of the technical aspects of their game,” added Ripley.
“I believe his cricket brain and experience are a real positive for the squad and will go a long way to improving their overall game.”
Former West Indies’ fast bowler Michael Holding has been appointed president of his former club Derbyshire.
Holding, 63, played for Derbyshire for six seasons from 1983 and described his new role as “a great honour”.
Derbyshire have also named local businessman Ian Morgan as their new chairman in place of Chris Grant.