rMiller, hello. I feel your problem , IMHO , I'd go to a Welding shop and get a Welding Blanket and cover the Smoker ( it won't burn , at the temps. you get it can't catch. But still watch out). That or fashion a windbreak around the Smoker . Wind-chill does a job on cooking outside. That's why I built a shelter (Q-Bana) to do Winter Smoking . Being 66 , I don't like cold much anymore , I'm not about to stop Smoking .
I will cover the Lattice with cheap plastic tarp when it gets cold...The heat off my pit will warm the inside to a comfy temp.
That reminds me , when cooking with a blanket or windbreak , use a probe therm. to track your temp. don't go by time , it is only a time frame for judging you time needed. Sometimes it will run over the time.
Be safe , have a good Holiday Season and as always . . .