Veteran comet observer John Bortle reports that Comet ISON is undergoing a major outburst. It was six times brighter when he observed it this morning (November 14th) than on the previous morning.
Bortle noted a short, faint tail while viewing the comet through 15×70 binoculars. At least one observer has reported seeing the comet without optical aid.
Bortle comments: "Just what this event signals for the future of C/ISON, with it now exactly two weeks from perihelion, is difficult to say. Over the next few days it should become apparent whether this event is the result of a single massive release of new volatiles; the nucleus having fractured; or perhaps even a dramatic permanent, sustainable, uptick in the comet's overall brightness."
The predawn sky also boasts another bright comet: Lovejoy C/2013 R1 — not to be confused with the famous sungrazer C/2011 W1, which was also discovered by Terry Lovejoy. Comet Lovejoy is currently roughly equal to ISON in brightness, and it's much better placed for observers in the Northern Hemisphere, above the constellation Leo.
The Moon will be lighting up the morning sky starting November 16th, but both comets should be bright enough to shine through the moonlight. Lovejoy should remain visible all month long for northern observers. ISON, by contrast, is rapidly approaching the Sun, so it's visible only low in the east just before the sky starts to brighten — and getting lower every morning.