The Toon host Chelsea at noon with the two clubs sitting level on points, with Newcastle in fourth and Chelsea fifth on goal difference.
On if the game is the biggest of their season, Howe declared this morning: "Yeah, I think every game we'll have between now and the end of the season probably becomes our biggest game of the season, maybe. The cup final is up there with that but now that's gone and that's behind us.
"We know the importance of where we finish in the Premier League, and we're doing everything we can to finish as high as we can. I think we've all said in this room there's a possibility it'll go to the last game.
"All we can do is take care of our next opponent and sort of try and give everything we can to win, and it'll be a difficult game. I think Chelsea are a good team, and we've played them twice already this season so we know their qualities.
"I think Stamford Bridge was one of our hardest games this season."
Newcastle fans will be in full voice
On the prospect of a midday game and whether it could affect the St James' Park atmosphere, Howe was confident the home support would rally to the cause.
He continued, "I think our home form has been pretty good throughout the season. It's a great environment to play in.
"I'm sure it will be a great atmosphere on Sunday, we need to crowd with us - we always say that - but it's absolutely imperative in these last two games that we know they will be for us.
"I think we have to be ready for the game. I think I've said before this week, sometimes with the early kickoffs they can just surprise you a little bit. You wake up and it's just very unusual for the players, and they have to adapt.
"Then the crowd has to adapt and we all have to adapt to be ready for the kick off and to be in full voice."
Champions League where we want to be
Howe admits qualifying for the Champions League is needed to meet Profit and Sustainability rules and splash out this summer. The Toon manager says another campaign in the UCL is what the club is demanding.
He also said, "I don't know the intricacies of our financial position depending on Champions League qualification. I don't think it changes too much, in terms of our targets and who we look to try and sign, just because we're trying to go for the best players in a very small pool of players to pick from.
"Obviously I think it's where we want to be, that's where we want to play, we want to be in the highest level competitions we can. We want to test ourselves to the absolute maximum and try and recreate those great nights here."
Chelsea will be fresh
Meanwhile, on what he expects to see from Chelsea, Howe believes they won't be affected from last night's Europa Conference League semifinal win against Djurgarden.
The Blues fielded a young team on the night and Howe added, "I think the game and the tie was pretty much dead with their comfortable lead.
"We expect them to, without going into too much detail, revert to near their last League Premier League side which was an impressive game against Liverpool.
"They've performed very well of late, with a lot of confidence, their attacking players back in form so yeah, it should be a good game."