According to people who actually live there, the state of Nevada's name is pronounced with a short a, thusly:
nuh-va-dah (pronouncing the "a" as in "cat")
not with a long a, thusly:
nuh-vaaaah-dah.
The only argument I've ever heard for pronouncing the state's name incorrectly is that it's how Spanish speakers would pronounce it. But that's not true. Here's how an actual Spanish speaker (whom I recorded at the bar, because I'm nerdy) pronounces it:
http://pacificstandardbrooklyn.com/memo.m4a
You'll notice that he pronounces the "d" in the Spanish way (more like a "th"), as opposed to the American way East Coast people pronounce it. In short, the East Coast pronunciation of "Nevada" is incorrect in both English and Spanish. Please, stop.