The capture of the pair – who were both part of the United States’ World Cup winning side of last summer - along with leading young English striker Chloe Kelly has helped hugely strengthen new manager Gareth Taylor’s squad.
Mewis has already begun training with her City team mates and made a brief appearance in last weekend’s friendly win against Everton while Lavelle is set to link up with her new team-mates shortly.
And, speaking ahead of this Saturday’s eagerly-awaited FA Women's Community Shield curtain-raiser against Chelsea at Wembley, Weir said she was confident the additions of Mewis and Lavelle to the squad can help City to hit new heights ahead of the 2020/21 campaign.
“To have players of that calibre come in is great. For them to have won a World Cup, it will drive us on to the next level,” declared the Scottish international
“To have players of their calibre with us with their mindset and winning mentality on the pitch is only a good thing for us all.
“I think Rose and Sam are what the squad needs. We were a bit thin on the ground at times last year.
“Gareth said there was going to be competition for places and I'm looking forward it. These players come with huge experience and are some of the top players in the world. It's exciting - I'm looking forward to it.
“Sam has been with us for the past few training sessions and she’s been great. You can see her qualities straight away - she’s physical, technical and it is great to be playing alongside players like that.
“She has got a winning mentality, and we’re looking forward to linking up with Rose too
“Chloe Kelly has been here since the beginning of pre-season. It’s been great to have her join and it’ll be great to get to know them even more when the season begins.”
For what will be the first FA Women’s Community Shield encounter in 12 years, it could not be a more enticing prospect with City locking horns at Wembley against reigning FA WSL champions Chelsea.
Though City led the table when the COVID-19 pandemic prematurely ended the campaign, Chelsea were awarded the title on a points-per-game analysis.
For her part, Weir says the opportunity to tackle the Londoners is the perfect way to launch the new campaign – especially with the match being played at Wembley and shown live on the BBC.
And she said playing Chelsea meant it would carry that bit more meaning and intensity.
“These are the games you want to play in when there's a trophy up for grabs against a team like Chelsea. It doesn't get much bigger than that and hopefully we can come out on the right side,” Weir added.
“Yes absolutely (there’s extra motivation in playing Chelsea). That's how they decided to end last season and we had to respect it - but it wasn't a nice way to lose.
“We are very motivated this season. The league is more competitive than ever, and it will give us an edge thinking about how it (last season) ended.
“Playing at Wembley is a huge message and it’s great for the game. Women’s sport has not really been on our screens during lockdown, so to have a game like this to kick things off is great.
“It’s what we need - a big occasion to get people talking about women's football once again.
“We've had a good pre-season. Now we need to focus on the season ahead and it’s really exciting.”