I will admit to initially brushing off reports of ISIS directly attacking Baghdad.  It just doesn’t make strategic sense -even for a terrorist group- for them to bog down in such a metropolitan geography with the citizen majority against them.
However, considering the aspect of unconventional warfare, there is some serious PR value in cutting off Baghdad from the outside world and slowly eating away at their capability to maintain stability.
ISIS now controls the rivers and dams upstream which feed into, and maintain, the Baghdad water supply.   And this recent video shows ISIS moving -what appear to be- Iraqi “Type 59” field artillery guns toward the outer perimeter of Baghdad central.

Does anyone know what the effective range on these are ?   I count about 8 of them in the segment of the convoy recorded.  Generally, they would be used in a battery of four, with intermittent fire toward a singular objective.   But who knows….