Hi robngerry, Welcome to cruise-chat! The Nov transAtlantic is at the end of the Med season so temps will be quite cool as you depart Barcelona. In the 60's for highs and 40's for lows at night. As your trip progresses it should get warmer with each day as you travel further south. Nov is still inside hurricane season and late in the season is often more active than early. The ship will steer clear of any major storm threats, they do have the equipment to forcast and avoid them. The ship can also cruise at speeds approaching twice the speed of such storms so I wouldn't worry much about that. The sea can be rough that time of year but Voyager of the Seas being among the largest ships sailing and having very good stabelizers, you'll be on a ship that can handle high seas well without the dificulty and discomfort for passengers of smaller vessels.
That cruise looks like an exceptional value right now and I love the Voyager Class of ships. I'd do it without hesitation. Just pack accordingly with clothing for cooler and wamrmer climates, it can still be very hot and humid in Galveston/Houston that time of year. Have a great time if you set this one up!