First of all, the models have converged to a solution which pretty much eliminates the chance for snow in the Ottawa area later this week. The system coming from the south will come up west of the Appalachian mountains. As such, Ottawa will be on the NW side of the storm as it comes up and will entrain "warm" Atlantic air.
That being said, it will not be a nice week with rain, wind and temperatures at most in the low teens for high and falling by weeks end. Saturday may be the nicest day of the week but cool.
The snow may have to wait for next week.