Hi JungleJoe and welcome to the forum.
I'm not a wind guy myself, but hung around long enough to give a basic run down... Since you've tossed a question in at the end that's more my speed, I'll go ahead and drop my two cents about the turbine first...
15 feet off the ground is likely to give you very poor performance, even if the unit can deliver stated output. Air nearer the ground is turbulent, which will cause a turbine to wag it's tail a lot and not produce much. Generally speaking, the higher you can get it off the ground (above tree line seems to be a bare minimum from what I've read over the years) and the further away from any other objects (out in a large field is good), the better the turbine will perform. The gurus will add to this, no doubt, but hopefully this gives you a rough heads up.
Solar loss in winter.. Well, there's basically 4 main factors that play into it... your elevation above the equator, the amount of precipitation you get (snow), what kinds of obstructions you have south of the panels (trees, etc), and how your panels are mounted (eg fixed/tracking, flat/angled and what angle (if fixed)...
Winter days get short, which really puts a pinch on the "solar day", which can translate into only a few hours of useable light on the clearest of days...
The angle of incidence (angle the light hits the panels) causes power to drop off, as well as the light traveling thru more air causing less energy to reach the panels to begin with.
If the sun has to get above any kind of a tree line to reach the panels, this will cut production significantly (particularly as you get further north) because PV does need direct light to perform optimally, of course.
There is one up side to winter, PV is more efficient at lower temperatures, so that part of it can balance out some.
Last but not least, frozen precipitation of any real amount (pronounced "visibly white") will render PV dead in the water. This readily will turn to snow packed ice, which can take it's sweet time going away. Particularly so if the air is still below freezing, but even when it rises up some. If it's thick enough, you can miss some good light this way unfortunately.
Hopefully this helps you out a bit, without more info about your array, I can't add very much more to that... And as I said, I'm a solar guy myself; the wind vets can tell you a lot more about what a turbine will do in a given situation.
Also, there are maps available that tell can give you a good idea of what to expect from your general location; nothing however beats collecting data about the area (via sensors and observation of existing equipment you have already installed). Logging is definitely your friend in that area, most will say a year of data before buying whenever it's possible.