Er...what miracles?
Extraordinary claims require extraordinary evidence. Which peer-reviewed scientific journals have documented these miracles?
What's more, even if a miracle was verified through scientific investigation, there would remain the possibility that we simply don't understand the phenomenon in question sufficiently yet, and that it could be explained through naturalistic means. Please note that I'm not saying that that would necessarily be the case.
Miracles observed by the medical community.
Medicine encounters things that defy reason and expectations all the time. There have been studies done on the effect of prayer on healing and patient recovery.
A verified miracle will not convince someone who doesn’t want to believe in God, but that leaves them with trying to figure out some other way to explain it.