Alolan Vulpix ?

[ArcNine]

I currently have 4 set up sweepers on my team:

Mega Lopunny with Power up Punch

Dragon Dance Gyarados

Contrary Leaf Storm Serperior

and Nasty Plot Naganadel

 

so i thought about, getting an Alolan Ninetales to set up Aurora Veil.

Where can i catch Alolan Vulpix ?

[Vanitas]

 

ametrine city grass

[Vinnie]

It should be in the grass of Ametrine City. 

 

You have also gotten it from a mystery egg in the early game(reward for breeding a police officer a new growlithe), however that's a 1-in-19 chance.