On the Futaba cam the view over the plant is quite dark. The light that flashes off to the left of the screen is active today (and it was blinking yesterday also). I presume it is some sort of warning light since it can be seen from the road to Daiichi but I could be wrong.
The TEPCO 1 cam view reveals an illuminated area behind unit 3, to the right of the giant vent stack, immediately over the building. This illumination is not typical and usually coincides, when it occurs, with subsequent emissions (based on my observations):