Jordan (70) and Meronk (72) have 54-hole totals of eight-under 208 at Doha Golf Club as they both search for their first European tour win.
The 282nd-ranked Jordan had a front-nine 39 in Saturday's third round but recovered with five birdies on the back nine in an overall "stressful" round.
"I couldn't get up and down," the Englishman said.
"But I knew I wasn't that far off. Fortunately enough, it all started to click. It was stressful but always very rewarding when you do well."
Finland's Samooja had a double bogey on the par-four second hole but added eight birdies in the day's best round, which he called "almost perfect".
Longtime leader Pablo Larrazábal (75) slipped two shots back in a three-way tie for fourth with fellow Spaniard Adrian Otaegui (70) and South Africa's Wilco Nienaber (74).
The Australian pair of Wade Ormsby and Jason Scrivener will need something special in Sunday's final round to get into the picture, as they both lie five shots off the pace at three under.
Ormsby couldn't get his challenge going, dropping three shots in the first eight holes en route to a one-over 73, but Scrivener had a better day, recording four birdies before a lone bogey at the last in his 69.
