But it's VHF. VHF is meant for hilly or mountainous terrain. So only 1 transmitter would do.Besides, Madison County is mostly flat with some small ridges to the east and west. They're not even 2 to 5 watt transmitters, so it wouldn't even make any sense.
VHF is line of sight. RF is a little farther than visual, but definitely affected by hills and other obstacles.
Look at the NWS propagation maps, you can see a graphical representation of the coverage.
I am a Ham radio operator (KE8DAF). I use VHF (2 meters) all the time. (a lower frequency than NWS)
Try driving around the California coastal regions and listen to commercial FM broadcasts (also considered to be VHF, but lower than the Ham band). You will get crazy multipath picketing and drop out null areas.
If the transmitter tower is at a high peak and the tower is tall enough, it can give reasonably large coverage. Still, areas will be below the line-of-sight rendering reception difficult.
Greg H.