Current trend in the models is throwing more moisture north hence the increased amounts:
Beyond this weekend: next week will gradually warmup due to a system heading through the western Great Lakes on Friday which is making for an ugly couple of days. Currently it is looking like that system will cause (in the Ottawa area) precipitation to start as snow Thursday night, change over to freezing rain then to rain on Friday. Then Friday night into Saturday, a strong cold front will pass through which will bring some more snow. My biggest concern is a flash freeze situation, as it looks like temperatures will drop ~ 25 C in 24 hrs.
As always, stay tuned.