I rode about 1000 km through the rain this winter in Vancouver on my skinny 23c, no threads. And no problems. Including on group rides with very tight pack riding. Our ride leader is very experienced and very concerned about security, and her comments were always about fenders, not tires.

Nonetheless, when I bought my new tires it was end of October so I asked the staff around the bike shop what they thought were good winter tires and they had some preferences.

So as maillotpois says: watch out for the breaking distance, and anything that's not strictly pavement. There may be more debris on the road if it's raining (from nearby trees or carried by the wind). Cornering will obviously have to be more careful. I don't see any other problem.

I don't mean to be overly optimistic, but... don't worry too much.

Enjoy the spectator role (for once!)...