Yeah, unfortunately, I think the whole bad conditions is what it going to work against you. You can't say, "But, judge, it was really bad out and there was a lot of snow" because it sets up the judge to respond, "Yeah, exactly - you should have been extra careful then."
You don't have any priors - that, I think, is the best thing you have going for you. Find the prosecutor before you get called up, tell him/her what you're looking for (e.g., a no-points violation, or at least not a reckless operation conviction), and offer something in return (e.g., to pay a big fine, to do 40 hours of community service), and hope you catch him/her as well as the judge on a good day.