The midfielder has been heavily linked with a switch to Goodison Park to reunite with Rafa Benitez.
‘I’ve been impressed with him’
It was the Spaniard who gave Longstaff his breakthrough while in charge of the Magpies and remains an admirer.
He’s out of contract at St James’ Park at the end of the campaign.
But head coach Howe stressed that he sees Longstaff as part of his plans as Newcastle bid to retain their Premier League status this season.
Howe said: “January is very, very intense for everyone connected with the club.
“Trust me, I think this has been the most intense January that I’ve experienced.
“In terms of our current players that are out of contract, they may well have to wait towards the end of January.
“Sean has a long-term future at this football club. I’ve been impressed with him since I come in. He’s been committed, trained well and earned his place in the team.
“Against Manchester United, I thought he was excellent. The whole team weren’t particularly good against Cambridge. We’re looking for a response from the team, and Sean is part of that team.”
Everton have already brought in three players this month.
Vitaliy Mykolenko and Nathan Patterson were signed on permanent deals from Dyanmo Kiev and Rangers respectively, while Anwar El Ghazi arrived from Aston Villa on loan for the remainder of the season.
Speaking at his pre-match press conference ahead of the Blues’ trip to Norwich tomorrow, Benitez says he is open to bringing more players to Goodison Park - but only if they’re an upgrade.
The Everton boss said: We are always hoping to strengthen the squad. If we have an opportunity available, we will try to do the best for us.
“The reality is we balance the books and it’s quite positive for the present and future.
“We’re always open to sany good option. At the same time, I’m pleased we’ve brought in three players this early.
“At the moment, we are happy with the three but are open-minded in anyone else who can improve the team.”