I'm in New England, too. Yes, it gets very dry in the winter!
The first thing you can do for humidity is to cover as much of the screen top with aluminum foil as you can, only leaving an opening for any heat source you have that needs to shine through it. Next, use a larger water dish and position it over the UTH or under the heat lamp or whatever you have. If that still doesn't do it, add another water bowl; or piles/handfuls of damp sphagnum moss or some other substrate that holds more water; or add another water bowl with a washcloth or sponge or paper towel sticking out of it to increase the surface area that water can evaporate from.
A full room humidifier might help some, but its effects will be limited. First, because a small humidifier that puts out a gallon or less per day into a whole room isn't adding very much at all to the small handful of cubic feet your snake lives in. And second, because warm air "holds" more moisture than cooler air, and the room is probably not 80 degrees in the winter. If the room is 60 degrees at 50% humidity, the same moisture content in the air will make it something like 25% humidity at 80 degrees. You can't humidify the room enough to keep the humidity in the cage appropriate unless you also limit the moisture loss due to ventilation.

Also, you should get a digital thermometer/hygrometer. Those dial ones are not reliable.