I can definitely say the local NWR I hunt that is mostly bottomland hardwoods, cut by sloughs and bayous and mostly flat... for whatever reason, the forecasted wind is almost NEVER the actual wind. At least so far this season, with the foliage still on the trees and all. I've wondered if there's some reason for this, maybe that the small draws and sloughs somehow funnel or alter the wind - like a S wind hitting a slough that runs SW-NE not only causes the wind to funnel up that slough (effectively making it more like a SW wind), but when that wind hits an opposing bank or line of trees, that causes back-swirl?
It could also be that wind is simply less consistent here 60miles from the coast.