Updated: Dec 5, 2019
We are closely watching the risk of some isolated snow squalls across portions of Southern Ontario extending to the southeast of Georgian Bay as to the east and southeast of Lake Huron.
A large patch of snow to the east and south of Lake Huron extending from Chatham through to Owen Sound and as far inland as Kitchener and Barrie can expect some light to moderate snow across Wednesday evening. Across Southeastern Ontario, scattered patches of light snow can be expected which will lead to the trace to 2cm described in the forecast map.
Into the late evening and early morning hours, the light snow will move out of the region with isolated, weak squall bands developing southeast of Georgian Bay across Simcoe County and southeast of Lake Huron across Huron-Perth-Grey-Bruce Counties.
Into the early morning hours between 2-4am, snow squalls are likely to develop across these mentioned areas with 1 large band off of Georgian Bay into Simcoe County across Collingwood, Barrie, and Midland. There will be 2 developing bands off of Lake Huron with one centered around Highway 8 in Huron/Perth Counties and another centered just north of Highway 86 in Grey/Bruce/Huron/Perth Counties. The snow squall to the south will likely be weaker and dissipate before morning (6-8am) while the northern snow squall will likely begin to weak and shift south during that time before weakening to scattered flurries by 10am-12pm. The Georgian Bay squall will stay persistent over the region until the late morning hours between 10am-12pm as well, therefore, snowfall totals over that region will likely end up being slightly high than the Lake Huron squalls.
At the strongest point, the snow squalls could be producing snow at 2-4cm/h. This is most likely on the Georgian Bay and Northern Lake Huron squalls. Elsewhere, snowfall rates will peak between 1-2cm/h.
Following these squalls, the remaining part of Thursday will end off clear before a weak clipper moves through early Friday morning and brings a widespread 2-4cm, locally 6cm across Southwestern Ontario extending to the GTA, Golden Horseshoe and even portions of Central Ontario.
Areas in the orange and marked with a '4' can expect snowfall totals between 10 and 15cm with local pockets between 15 and 20cm. This extends in two areas across Southern Ontario. The first region extends from Lake Huron inland from Kincardine and Amberley through to Wingham, Minto, and Mildmay. Snowfall totals will likely peak around 15cm across this region, although an isolated band of 15-20cm is possible, especially from Kincardine inland towards Walkerton and Teeswater. The second region extends from Georgian Bay Bay between Balm Bay and Wasaga Beach into Barrie. Snowfall totals are likely to reach between 13-17cm with isolated totals at or slightly above 20cm in the Elmvale-Craighurst-Anten Mills region.
Areas in the yellow and marked with a '3' can expect snowfall totals between 10 and 15cm. This includes two defined regions in Southern Ontario. The first taking over a large portion of Southwestern Ontario the east of Lake Huron, a majority of Huron and Perth Counties extending from Goderich through to Stratford as well as inland to Listowel and Elmira are included in this area. In Bruce, Wellington and Grey Counties, this region includes Underwood, Hanover, Mount Forest, and Arthur. Snowfall totals will likely remain around 8-12cm for most with areas such as Brussels, Elmira, Underwood, and Durham. Near 15cm is possible for places that receive consistent squalls. This is most likely between Goderich and Stratford along Highway 8 as well as extending inland from the orange region to include Listowel and Mount Forest. The second region in Southern Ontario extends across much of Simcoe County into the York Region. This extends from Georgian Bay near Christian Island through to Midland, Horseshoe Valley, Simcoeside, Sutton, Keswick, Bradford, Angus, and Stayner.
There is the potential that the Georgian Bay remains slightly further south between Collingwood and Barrie. In this case, areas such as Midland and Christian Island would be pushed down in the legend to the 5-10cm range. At this time, we have not highlighted this on the map, although this is certainly possible. This situation also is in place across much of Perth County due the localized nature of the squalls and the position, much of this county could bypass the core aspect of the squalls and only be left with 4-8cm.
Areas in the green and marked with a '2' can expect total snowfall amounts between 5 and 10cm. This extends in two large regions across Southern Ontario. The first is for areas east and southeast of Lake Huron extending from Highway 8 south to areas just north of Grand Bend extending into Lucan, Exeter, Thorndale, Woodstock, Ayr, Kitchener, Guelph, Grand Valley, Priceville, Chesley, and Port Elgin. The second region extends from Lake Simcoe and Georgian Bay southeast into portions of the Northern GTA. This includes Coldwater through to Washago, Orillia, Georgina Island, Uxbridge, Newmarket, Oak Ridges, Tottenham, Creemore, Collingwood. The majority of these named regions will see between 4 and 6cm with pockets of 5-8cm and 8-12cm the closer towards the yellow and orange regions.
Elsewhere, areas in blue and marked with a '1' can expect total snowfall amounts under 5cm. This includes most of Southern Ontario with a trace expected. Pockets of 2-4cm are possible across Chatham, Elgin, Dufferin, Lambton and Middlesex Counties.
Over the coming weeks, we will be testing our new maps and are looking for feedback on the maps.
We have a wide span of maps extending from Southern and Northern Ontario maps to more localized areas such as Prince Edward County and Kingston, Niagara, Southeast of Lake Huron, Southwestern Ontario (this map), Northeast of Lake Huron, East of Lake Superior, Southeastern of Lake Nipigon, and around Lake of the Woods.
The localized maps will be used for small events like squalls or isolated severe thunderstorm events and the larger maps will be used for big events like widespread snowstorms. With these new maps also comes with the change in layout. We have went with less places, more roads and easier to read colors with the theme now being dark instead of light.
The format for the legend also is clear now with the unused colors not existing in the legend as well as larger text and a larger map overall.
Please let us know what you think in the comments or on social media.