I was going to say that yes, you can weigh in on 16th and then pull it forward on the 18th like posted above. I was also allowed a one time early weigh in due to travel. That was in 2022 so I’m not sure if that’s changed. Good luck!
Jessica is correct. I suggest submitting an official weigh in before you leave on the 16th and set a reminder for yourself to reuse that weigh in on the morning of the 18th. Good luck!
For those looking for a digital tracker, I created this for myself and decided to make a copy that others could use. This one was made for my goals and what I'm tracking so please customize for yourself. https://docs.google.com/spreadsheets/d/1ggwMXaskYgMJfRgYjRw-sanxGHadS-HDULlS5tT-9ak/edit?usp=sharing