I would add, especially with a smoker such as you described, there is no shame in baling after a couple of hours or so and bringing the brisket into the oven for cooking. There are some cookers that are just not good in bad weather.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
Whip It Off, Chambers!
"perhaps...but then again...maybe not..."