Ann Curry writes: It appears Egypt is nearing a "tipping point," as NBC Richard Engel puts it, with tomorrow's planned demonstration in Cairo expected to be the biggest yet.
Which is why Brian Williams has been spending a lot of time on planes, flying to Egypt to broadcast live from there tonight, despite some overwhelming technical odds against success.
I write this preparing to co-anchor the broadcast from New York, and can tell you our plan is to report in-depth on this gathering storm, and on the evacuation of hundreds of Americans today. We’ll have reports from Cairo, Washington and Israel.
On top of that, we have another storm to tell you about, this one of snow and ice, that's predicted to affect no fewer than 30 states.
It's intense here behind the scenes, the clock ticking as everyone scrambles for tonight's broadcast.