Why did Murphy underperform in Somerset?

[Tekken_Guy]

Clinton won this county quite handily in 2016 but Murphy barely beat Guadagno a year later. What happened?

[Progressive Pessimist]

Guadagno's campaign was doomed to lose and as such she focused on the number one motivator for NJ's GOP base-property taxes. This may have caused a surge in wealthy suburbanites coming out to vote for her who didn't really care about Christie's unpopularity.

As for 2016, these people are probably culturally moderate or liberal  and well-educated enough that Drumpf had little to no appeal to them. They did still ticket split for Lance too, which is also worth mentioning. Oddly enough though, here in Bergen county where I live, some of those upper class Clinton towns still voted for Murphy such as Oradell. I'm not sure why that was because those voters are probably demographically similar to most voters in Somerset or Morris counties'.

Also I remember going out to vote that day, it was raining pretty badly so that may have also dampened turnout among Democrats across the entire state who already knew Murphy was going to be victorious. There was dismal turnout for this election after all, even worse than usual. That may also have played a part.