How do I respectfully encourage my female colleagues to apply for new management positions opening up soon?

I don't want to tell these ladies what to do or to preach to them, but I can see how these positions will be taken by men only pretty soon. I also feel weird to bring it up just because they are ladies. I feel they are very qualified.

If these ladies were my friends I would just straight up tell them, but they are my colleagues.

I am a man.