Recent mesoscale analysis of the system headed into the east:
This disturbance is expected to intensify into the 980mb range as it tracks through the GL and brings another slug of heavy moisture in the wake of the soggy low earlier in the week.
Rain looks to change to some snow as colder air becomes involved on the system’s flank. Areas in ON and QC are likely to see a swath of higher accumulations in the 10+cm range northwest of the more highly-populated urban regions in the south & east and where elevation plays a role. There could be enough backside snow to eventually lead to some lesser amounts outside of the target areas but the bulk of the moisture should fall as rain before this occurs.
This the 12z GFS total precip and precip-type @ hour 96:
The snowfall maxima portrayed in NE ON is a common feature among the various models, along with the corridor arcing through parts of QC.
Farther east towards the Maritimes this storm is set to introduce a notably milder flow and primarily rain as it passes west of the region.
12z CMC @ hour 60:
Cooler conditions behind this storm aren’t going to have much staying power for many of the affected regions as warmth gains a major foothold into next week.