No real proof on wether this is true or not, but Gina Cherundolo of AccuWeather.com has a theory on why the ball is traveling so well at Yankee Stadium.
Here is an excerpt from the article:
Although the field dimensions of the new stadium are exactly that of the old stadium, the shell of the new stadium is shaped differently. AccuWeather.com meteorologists also estimate that the angle of the seating in the new stadium could have an effect on wind speed across the field.
The old Yankee stadium had more stacked tiers and a large upper deck, acting like a solid wall in effect, which would cause the wind to swirl more and be less concentrated. The new Yankee stadium’s tiers are less stacked, making a less sharp slope from the top of the stadium to the field. This shape could enable winds to blow across the field with less restriction. In addition, the slope of the seating would also lead to a “downslope” effect in the field which, depending on wind direction, would tend to cause air to lift up in the right field. Fly balls going into right field during a gusty west wind would be given more of a lift thus carrying the ball farther out into right field.
If the stadium seating tier shape is indeed the issue, games will only be affected during times with the winds are from a westerly direction and above 10 mph. This typically occurs during the spring and the middle to late fall. The calmer weather during the summer should lead to a smaller number of home runs. In the meantime, the home run derby may continue.
Pretty interesting. We will have to see over time if the theory is proven.
Anyway, the stadium has another test: How it plays at night?