I know from personal experience, if you shut down your WUnderground for more than 2 weeks, you won't be able to go back.
At least that's what happened to me. About 4-ish years ago, WU was having troubles with my Bloomsky pics. I created a new WU station for testing. It worked, for 2 weeks. Then it puked too. I tried going back to my original account and it wouldn't let me. I "had" the second station in my city for 10 years. Lost that #2 position. So now I'm at #26.
I still upload to WU, but upload data. All WU content I removed from my site.
As far as the website goes, I've added text to my Saratoga scripts header.php before. You can add downtime. In my case, I have text letting everyone know I have a webcam now. I'll leave it up for a month.