Armstrong has netted 12 goals in 14 League One appearances this season, and his good form has seen his stock rise.
Many are calling for the 18-year-old to be handed a chance in Newcastle’s first-team when his loan expires in January, while the Chronicle reported yesterday on Wolverhampton Wanderers’ supposed interest.
But Mowbray said: “He’s doing really well and if he stays here all year he’ll still only be 19.
“If it was me I wouldn’t be in too much of a rush to burden an 18-year-old with keeping Newcastle United up. Ultimately, it’s their decision.
“I’m not in constant contact with Newcastle but the strong message we are getting is that they are pretty happy with the way things are going.”
Newcastle’s strikers have not been particularly free-scoring, and there is a feeling among supporters that Armstrong would enhance the quality of their forward line.
Although the youngster is developing, his pace has caused defenders in League One a number of problems.
If he does return to Newcastle, he would be competing for place in their starting line-up with the likes of Aleksandar Mitrovic, Papiss Cisse and Ayoze Perez.