The lake-effect snow machine is back in action in southern Ontario this week, with heavy accumulations possible for some by Thursday morning. And while a clipper system skimming through by week's end won't bring significant accumulations, it could have a major impact on commute times across the GTA on Friday. More on the timing of this week's snow potential, plus a look at the overall December pattern that looks to bring an active storm track, below.
- Snow squalls continue into early Thursday afternoon
- Poorly timed clipper Friday morning could have a significant impact on commute times in the GTA
- Stay up-to-date on the ALERTS in your area
THROUGH THURSDAY MORNING -- SNOW SQUALLS LINGER
Snow squall bands developed Wednesday afternoon off of lakes Superior and Huron, as well as Georgian Bay, and the pre-dawn hours on Thursday will be some of the roughest for travel in the typical snow belts of southern Ontario.
Accumulations of up to 15 cm are expected for some spots by Thursday morning. Places like Sault Ste. Marie, Midland and Orillia, and the Dundalk Highlands, where squalls are likely to be the strongest and stay in place longest, are expected to have the highest accumulations. Elsewhere, meandering snow bands will leave anything from a dusting to 10 cm.
Streamers could pose challenges for the Thursday morning commute, particularly down Highways 400 and 404.
The snow squalls will begin to weaken late Thursday morning as winds shift, with an additional 5 cm possible in some areas by Thursday afternoon.
FRIDAY -- POOR TIMING FOR WET SNOW
A potent clipper system is expected to track across southern Ontario late Thursday night and into pre-dawn Friday, making for a poorly timed wet snow event for the morning commute in the GTA.
While 2 to 5 cm isn't necessarily a significant amount of snow, it could be enough to slick up the conditions, especially on any untreated and highly travelled roads.
Daytime high temperatures on Friday will also occur earlier in the day, falling steadily by the afternoon hours with a gusty wind expected. That could fire up another round of lake-effect snow for areas southeast of Lake Huron and Georgian Bay.
LOOK AHEAD -- MILDER HIGHS AHEAD OF NEXT SYSTEM
Sunday looks like the ideal travel or shopping day of the weekend as temperatures get a boost ahead of the next system. "If you still plan to put up lights for Christmas, this is your day to do so," says meteorologist Dr. Doug Gillham.
That's ahead of another significant Colorado low for the start of next week, though at this point, it looks like it will bring primarily rain and milder temperatures to the region this time around.
As for December overall, "changeable" will be the best way to describe the pattern shaping up in the coming weeks.
"But changeable patterns are often active patterns, and we expect that this December will have more winter storms than we saw last December," says Gillham.