You may be technically able to, but you'll run into a problem filling the form: When you list all your travels outside the US, you'll end up with the last one not being closed. As such, you cannot determine your length of stay outside of the US and whether you end up staying more than 6 months outside the US or not.
This site suggests that you cannot apply online while abroad. Generally applications from abroad are intended for family members of military personnel or government employees (which do not have the 6 months restriction).
In your case, I'd suggest to wait until you're back after your short vacation and file without any unnecessary complexity. While trying to save a couple of days you may end up prolonging the process just because the USCIS will look into the unusual circumstances with more scrutiny.