Flame&Frost
Flame and Frost: Prelude goes live today. I do not believe an exact time that the patch will go live has been announced. We will just have to wait.
Also, I do not think there is an event associated with this patch, like we saw in holiday content. There is a narrative, I suppose. But, I am not sure we are going to see anything like the last three events.
Beat Reporter at www.guildwarsinsider.com
Based on previous experience, content updates tend to go live during the second half of their workday.
In Central European Time, that would be anywhere between midnight and 3 AM. However, for this particular update, I would not be surprised if it was released at the exact moment daily achievements update, which is at 1 AM CET.