Those in central and eastern sections of Ontario should brace for difficult travel Wednesday evening through early Thursday as a favourable, atmospheric setup for an extended period of freezing rain will lead to ice buildup, travelling and power impacts for parts of the aforementioned regions.
A Bermuda high will act as the the main gear in a conveyor belt of moisture being ushered north from the Gulf of Mexico this week. At the same time, high pressure from Canada's North will be the gatekeeper to much cooler air that will get funnelled south.
The two air masses will meet over Ontario, leading to a fury of heavy rain and a swath of snow, with a prolonged freezing rain event in between.
As the moisture meets cooler air towards the Ottawa Valley and the Ontario-Quebec provincial border, precipitation will transition to snow, freezing rain and ice Wednesday and into Thursday.
While rain will still be expected for much of southern Ontario, a swath of freezing rain will develop across parts of cottage country and eastern Ontario through the majority of the afternoon and evening on Wednesday.
Ice accumulation could be between 5-10 mm in regions that see the most prolonged period. There is still some uncertainty as to where the greatest ice accretion will be, however, so continue to check back in with the forecast.
The ice accretion from freezing rain could cause travel issues, and possible damage to trees and power lines in the hardest-hit areas.
A heavier swath of snow is forecast on the northern extent of this system, potentially spreading 10 to locally 20+ cm of snow to northern cottage country, North Bay and north of the Ottawa area.
Ottawa remains a tricky forecast, however, as it is riding the line between seeing significant snowfall or more of an ice pellet event, depending on how far north the warm air nudges.
Widespread flurries on the backend of the system Thursday can be expected across southern and eastern Ontario as the upper low associated with the system swings through.
Temperatures will start to fall back toward seasonal behind this system, with daytime highs around the freezing mark expected for much of the region by next weekend.
Check back for the latest on conditions across Ontario.