We are watching a large system cross Northern and Far Northern Ontario bringing a widespread 3-8cm of snow. The heaviest snow will fall across Far Northern Ontario extending from Hudson Bay south into Central-Northern Ontario. Lake-enhancement from Lake Nipigon and Lake Superior should increase snowfall totals, possibly significantly, to some isolated areas.
The system should move through the region on Tuesday into Wednesday with lake-enhancement off of Lake Nipigon at the same time. Snow squalls from Lake Superior will begin early Tuesday morning before lasting through to Thursday morning.
Areas in yellow and marked with a '3' can expect snowfall totals between 10 and 25cm of snow with local snowfall totals near 30cm. In Far Northern Ontario, a widespread 10-20cm can be expected from Hudson Bay near Winisk inland to Moshikopaw Lake and Opinnagau Lake. This includes Spruce Lake and Peawanuck. Snowfall totals between 20 and 30cm are possible between Peawanuck, Winisk and Hudson Bay towards the west, around 130km northwest of Peawanuck. In Northeastern Ontario, lake enhancement and snow squalls off of Lake Superior will lead to snowfall totals in the 15-20cm range, although, local totals towards 25 and even 30cm are possible throughout this region directly east of Lake Superior. This includes Agawa Bay, Montreal River Harbour and Batchawana Bay. The heavy squalls may reduce visibility to near zero at times. Road closures along Highway 17 are possible.
Areas in the green and marked with a '2' can expect snowfall totals between 10 and 15cm with local snowfall totals near 20cm. In Far Northern Ontario, a wide swath of 10-15cm of snow can be expected from Fort Severn south towards Kingfisher Lake and Kasabonika. This includes Summer Beach, Webequie and Lansdowne House. Towards the east, this includes Missisa Lake and Eastern Polar Bear Park. Snowfall totals should remain around 10cm although areas closer to the highlighted yellow or '3' region could see near 15cm. Local totals of 20cm are possible closer to this region as well. In Northwestern Ontario, near Lake Nipigon, lake-enhancement may lead to snowfall totals in the 10-15cm range over Lake Nipigion extending into Jellicoe and Beardmore. Isolated pockets of near 20cm may be possible if the lake-enhancement bands remain stationary over a period of time. This is highlighted by the area of interest. In Northeastern Ontario, snowfall totals in the 10-15cm are likely from Pukaskwa Park through to Lake Superior Park into Ranger Lake as well. This also includes Searchmont. Most places should see near 10cm although areas between Ranger Lake, Searchmont and Lake Superior Park could see the totals higher towards 13-18cm. Areas slightly inland from this region towards Mashagama Lake and Mewburn Lake could see local totals near 20cm.
Areas in the blue and marked with a '1' can expect snowfall totals under 5cm. This includes the remaining portions of Far Northern and Northern Ontario. Most places will see between 2 and 4cm with some isolated pockets of snow additional snowfall. Areas around Lake Nipigon towards Lake Superior (both the north and east side) could see snowfall totals in the 4-8cm range. These local snowfall totals of 4-8cm are also possible in the Fort Hope, Ogoki, Attawapiskat and Big Trout Lake regions.
We will continue to monitor the progress of this system over the next week and will update as needed.