Rasmussen Reports tends to come up with poll results that are overly favorable to Republicans, so you have to consider when you see the news that a new Rasmussen poll actually has Trump leading Hillary 41-39 in a hypothetical general election matchup that might be a lot less hypothetical by this time tomorrow.
Any one poll can be an outlier, and for lack of any trend in this direction we'd have to say there's a pretty strong chance that's the case here. Also, Trump's "lead" is somewhat conditional: