Winds and groundspeed don't have a place in those equasions that I can see.
Well, you will usually want to "hover" at a specific spot. The area you want to observe, or the holding you need to maintain. So your airspeed needs to be at least equal to the windspeed otherwise you're being blown away.
But in the far majority of cases your best endurance speed will be higher than the windspeed so then it's not a factor indeed.