Ryan Evans got the scoreboard moving with a brace of tries after which Ross Moriarty and prop Nicky Smith crossed the whitewash to secure the all important bonus point.
Sam Davies popped over two conversions and a penalty whilst for Gogledd Cymru, Aaron Evans and replacement prop Rhodri Evans helped themselves to tries. Full back Dion Jones kept his side in the hunt with two conversions, a penalty and a drop goal, but they left for home with nothing more than a losing bonus point for their considerable effort.
Victory takes the Ospreys to within four points of Blues South, albeit with a game in hand over their nearest rivals.
The next round of games, on Wednesday night, sees the Ospreys entertain the Dragons whilst Blues South make the journey west to play the table topping Scarlets.
Meanwhile the Ospreys under 18s were 31-0 winners over a plucky Gogledd Cymru who performed with great gusto despite failing to register a single point.
Difficult conditions made life particularly tough for both sides although credit must go to all 44 players for making this an excellent game.
Admittedly, in the end, the Ospreys utilised their greater strength at forward to close the gap on runaway leaders, the Scarlets, and the second placed Blues.
However, the North never once too a backward step and took great praise for the manner in which they battled until the final whistle.
Team manager Will Morecombe said; "The weather was awful, but I would have to say that both sides deserve great credit for the way they played in very blustery conditions.
"Although the Ospreys ran out convincing winners, the Gogledd Cymru side contributed fully throughout and can take a great deal from the game."
The Ospreys took an early lead courtesy of tries from Andrew Claypole and Tom Haberfield before Eli Walker added a third to leave the host region 19-0 to the good at half time.
Morecombe added, "It would have been all too easy for us to give up at that stage and to accept the inevitable. However, their heads never once dropped and we can be proud of that much.
"Chris Holmes, JJ Williams and Gareth Morgan in particular, were outstanding contributors with some measure of parity being established at the breakdown."
However, as fatigue set in, it was the Ospreys who pulled away with Leon Ward and Matthew Morgan adding further tries.
Lloyd Thomas kicked two conversions and Cameron clement a third as the Ospreys closed the gap on the Blues to three points.