Mr. Fybush is right. However, to the poster that inquired why doubling the power may be a bother..........
While WGNY will range a few (or more than a few) miles in direction, the power increase will solidify it's present contour: it will become louder and stronger where it is heard right now.
In order for an AM station to "double" its contour it has to increase it's wattage 10 times.
Example: if a 5,000 watt station wanted to go 50,000 watts, it would, in theory increase it's coverage by twice. Of course, directionality and ground conductivity has a lot to do with it, but that is the general rule of thumb.
Carl