We are tracking a large low-pressure system which is producing strong tornadoes and severe thunderstorms across the Deep Southeast United States. This system will move north bringing heavy snow to portions of Northeastern Ontario extending from Lake Superior to James Bay. Brief freezing rain and ice pellets along a mixing line are possible with breezy winds.
Southern Ontario Wind and Rain: https://www.weatherwatcher.space/post/heavy-rain-thunderstorms-and-strong-winds-target-southern-ontario
Areas in the red and marked with a '5' can expect snowfall totals between 40 and 60cm. This extends from James Bay near Moosonee through to Onakawana, Otter Rapids and on Highway 11 between Kapuskasing and Hearst. Snowfall totals will average near the 50cm mark although amounts closer to 60 and even local totals to 70cm are possible across this region. The best risk for local totals will extend from Hearst through to the rural landscape west of Onakawana.
Areas in the orange and marked with a '4' can expect snowfall totals between 25 and 40cm. This extends from James Bay to the north of Fort Albany, including Fort Albany extending southwest towards Mammamattawa and Pagwa. Snowfall totals averaging near 35cm is likely across this region with local pockets higher. Towards the south, areas between Hillsport, Manitouwadge, and Marathon can expect amounts closer to 25 and 30cm while totals near Hornepayne, White River, and Dubreuilville reach towards 30 and 35cm. Towards the northeast, near the Quebec border, areas across Kesgami Park through to Smooth Rock Falls can expect amounts near 30cm with locally higher towards the north and locally less towards the south. Areas around Wawa extending towards the mixing line (near Timmins and Chapleau), snowfall totals near 25cm are expected although locally more or less is possible depending on how far north the mixing line pushes.
Areas in the yellow and marked with a '3' can expect snowfall totals between 15 and 25cm. This extends from Attawapiskat to the southwest. Snowfall totals between 20 and 30cm are most likely in this region, with 30cm on the high end. Towards the south, areas north of Lake Superior near Terrace Bay and Longlac can expect snowfall totals between 20 and 25cm, with 15 to 20cm closer to Lake Superior. Across the northeast, 15cm is expected near Chapleau, Foleyet, Timmins, Iroquois Falls, and Cochrane where the mixing line is expected. If this shifts north, amounts may be reduced while if the line shifts south, amounts towards the higher end of the scale will be possible.
Areas in the green and marked with a '2' can expect snowfall totals between 5 and 15cm. This extends in three defined regions. The first region in Northeastern Ontario extends from the Quebec border through to Montreal River Harbour where the mixing line should sit just north of. As the mixing line shifts north in the morning and south again into Tuesday, this region should see some minor snowfall between 5 and 15cm, although the exact amounts will vary. Into Northwestern Ontario, snowfall totals from Slate Falls through to Savant Lake and Thunder Bay will range between 10 and 20cm with an average of 15cm. As the system pushes off the to east into Quebec, a snow squall is expected to develop across Northwestern Ontario connecting to Lake Superior and even Lake Huron. This band may last for a few hours as it shifts back and forth, briefly. This will result in a thin band of 15cm with local pockets up to 20cm, otherwise, a general 5 to 10cm is expected. This is highlighted in the area of interest. For areas south of Lake Nipigon, local snow squalls after the system on top of system snow will provide amounts near or above 10cm across Gull Bay through to Beardmore and Nipigon. Into remote Northern Ontario, snowfall totals between Kowkash and Ogoki will range between 5 and 10cm with up to 15cm closer to the east.
Areas in the blue and marked with a '1' can expect snowfall totals between a nothing and 5cm. A majority of the region will see no snowfall, although a few pockets may pick up on some isolated flurries.
Areas in the yellow and marked with a '3' can expect freezing rain totals between 4 and 7mm. This is expected from Chapleau through to Foleyet, Timmins, and Cochrane, where freeing rain will be persistent the longest as it aligns on the mixing line.
Areas in the green and marked with a '2' can expect freezing rain totals between 2 and 5mm. This extends from the Quebec border, south of Kesagami Park, through to Iroquois Falls and Lake Superior.
Areas in the blue and marked with a '1' can expect freezing rain totals between a trace and 2mm. This extends from the Quebec Border through Matheson and Gogama over to Montreal River Harbour. Many places in this region won't see any freezing rain due to quick changeover to rain, although areas closer to the north such as Matheson may see a trace or so.
Amounts will vary based on the exact mixing line. With winds gusting between 50 and 80km/h, it's hard to say exactly how much of this ice will accrete. Accretion totals, at the peak, should reach towards 5mm.
Areas in the orange and marked with a '4' can expect wind gusts between 90 and 100km/h at the peak. This is expected along the shores of James Bay in Fort Albany through to the shores of James Bay, just north of Moosonee.
Areas in the yellow and marked with a '3' can expect wind gusts between 80 and 90km/h at the peak. This is expected near James Bay and Hudson Bay extend from Polar Bear Park through to Attawapiskat through to Moosonee. Wind gusts between 80 and 85km/h, locally 90km/h are possible along the North Channel and across Georgian Bay, along the south shores of Manitoulin Island into Britt and Parry Sound.
Areas in the green and marked with a '2' can expect wind gusts between 60 and 80km/h at the peak. Across Northeastern Ontario, the peak is expected to range between 65 and 75km/h with less towards Thunder Bay and the west, and locally more towards Lake Superior.
Areas in the blue and marked with a '1' can expect wind gusts at the peak to remain at or under 60km/h.