I caught a breeze like that blowing through my stats recently. I wonder if G doesn't salt the numbers a little bit, say by attributing a few bucks or clicks to the following day occasionally. Not enough to mess up your 7-day moving average, but enough to make trying to ride the daily numbers a non-starter.
In my case, a morning check showed a handful of clicks returning an average EPC of over 8x my running average. By the end of the day it was gone.
Is it just me? My stats are the same as they were around 10 am and it's now 5 est. I don't think we can go on anything till things are updated (I have to believe they haven't been updated in several hours- or I'm having a REALLY bad day).