[Suhiir]

The interesting coincidence of my scenario is that it just happens to take place in the Fall which by every measure is the best time to invade.

Winter - Obviously not a good idea
Spring - Ground is too wet/marshy for any significant maneuver
Summer - Doable, but still a lot of wet ground
Fall - Ground is as dry as it ever gets, weather is still reasonable

So the more I play with it an Oct 1963 invasion to gain political leverage for missiles in Cuba looks "reasonable". If operations are confined to northern Norway it's not too likely anyone will start launching nukes, and that's obviously a major concern.