I recall once, when driving in rain, a noise like yours started, after
checking a few parts of the car i found a piece of cardboard stuck with
bubble gum and the noise was the cardboard hitting the moving air.
A deal of road noise could be tyres, a slipping fan belt or your thermo fans
coming on at high speed. You could try jacking your car up on stands and
move the wheels by hand, sounds like something has worn a fan belt or air
hitting some thing causing your noise and any noise seems to magnify as you
drive along. Check also your power steering belt, ac belt and any other
belt, i spray mine with belt lube, trial and error done quickly could not
see you forking out dollars over some thing that could be in the end so
small a thing.
Hope i have helped