Winter is coming

Hi everyone,

I'm just having a question with translating English mottos to Latin. So for example, how would I translate "winter is coming" to Latin?

I know "winter" is hiemes or so, but should it be in nominative, accusative, or provocative? (And do we always translate nouns from English mottos into that case?)

Also, how do we translate the "is coming" part?

Thank you very much for your help in advance!