A number of European states have updated their travel advice for the U.S. since the Trump Administration came to power.

Be careful with the terminology here. I’m not familiar with the the specific background in Norway, but at least where I live there are legal differences between official foreign ministry “travel warnings” and “travel advice” and you’re using both terms.
Whether it’s one or the other here can determine whether your travel agent has to fully reimburse you for your 5000€ vacation ticket or not, for example (if I remember correctly).