I have a 2010 and just started experiencing this as well. Flutelike noise travelling around 70 mph and also seems to happen primarily in 90 or above temps. . Sound appears to come from the windshield/front pillar area. I'm going to start taping the side mirror seams and the seam between the door and the body to try to track down the source of the noise. I suspect the door weatherstripping is doing something weird in the heat.
I have the same problem with my 2010 explorer. It does in fact seem that it is heat and temperature related. I recently noticed it after I drove 11 hrs from Ohio to South Carolina and the whistling only started until I reached the 90+ degree temps. It's very annoying. Does anyone think that those window vent/shades would make this go away? I also pulled my mirror in and noticed that it went away. I figured that its because I changed the way the wind went past the windows.
I had exactly the same problem, dealer replaced the window seal, sound was still there. They taped the windshield seal and it stopped. So they resealed the windshield and so far it has stopped. BTW they said that they had not ever heard of this issue, I printed out all the post I got on the internet and showed them mine was not the first one with the whistle.
Same thing on my 2010 Explorer. Seems to be brought on by high temperatures and high windspeed. I purchased windshield gasket sealent and filled in the cap between the bottom of the windshield and the frame. This seems to have worked. I didn't want to pay to have the windshield pulled.
I willing to bet that this happens on days with temps above 85 degrees. Ford has replaced my windshield 3 times and IT STILL DOES IT! This is heat related as my Explorer does NOT do this during the Winter months. I really believe it is the sealant that is the problem. To prove my point, on a hot day, install black electrical tape where you think the sound is coming from, take your drive. My money is that it is gone. NOW, go get some silicone sealant, cut a small hole in the tube, carefully and slowly lift up the rubber seal around your windshield as you insert the sealant under the rubber seal. Now take that black electrical tape and apply along the rubber molding to hold it in place for about a day or two. Remove the tape and IF you put enough silicone sealant under the rubber molding, the sound should be gone.
YOU would think that the ford engineers could have come up with this but "NO" they just kept replacing the windshield EVEN after I told them that this wind noise is "heat related" and the sealant they are using breaks its bond at temps above 85 degrees. Anyway, it works and now I don't have to put up with that wind noise anymore. Another way to stop that wind noise,,,,,turn UP the radio until YOU can't hear it anymore.
HAVE A NICE DAY.