***NOTE: YOU CAN CLICK ON THE MAP TO OPEN A ZOOMABLE IMAGE***

A shift in the weather pattern across Southern Ontario over the past few days has brought a noticeable retreat from the extreme cold, with temperatures returning to near-seasonal values. However, this shift has also placed the region on a more active storm track, a pattern we first experienced with Monday’s messy system.

The next round of unsettled weather was initially showing signs of a prolonged freezing rain event on Thursday. However, recent model trends indicate a significantly weaker system than previously expected. While this storm will still impact Southern Ontario, the main threat now appears to be light freezing rain and snow, particularly during the Thursday morning commute.

Although snowfall totals won’t be overly impressive, Central and Eastern Ontario could see an average accumulation of 4 to 8 cm by the end of the day. The primary concern will be the mix of precipitation types, which could create slushy and icy road conditions, making for a slick and potentially hazardous commute.

Looking ahead to the weekend, we are closely watching a moisture-laden system that could bring Southern Ontario its first true widespread snowstorm of the season. This storm has the potential to impact even those regions that have largely avoided significant snowfall so far, including Deep Southwestern Ontario and the Golden Horseshoe.

Current projections suggest snowfall totals could range from 10 to 25 cm, though these estimates will likely be refined as we get closer to the event.

**PRECIPITATION TYPE OVER LAST 6 HOURS** - MAP FROM WEATHERBELL

Thursday’s system is expected to begin during the morning hours as light precipitation moves in from the southwest. High-resolution models, such as the American model shown above, suggest that the precipitation will be quite scattered with dry pockets throughout. However, if the precipitation takes the form of light flurries or drizzle, some models may be underestimating its extent.

For Central and Eastern Ontario, precipitation will likely fall as snow. Across the Golden Horseshoe, it may also start as snow during the mid-morning hours before transitioning. Meanwhile, areas along the Lake Erie shoreline and Deep Southwestern Ontario will be more prone to freezing rain and ice pellets from the onset.

Travel conditions could become challenging, particularly in the morning as freezing rain coincides with rush hour across Southwestern Ontario and into the Golden Horseshoe.

At this point, it’s uncertain whether this system will be strong enough to prompt widespread school bus cancellations. However, the highest risk for disruptions will be in Windsor, Chatham, and London, where precipitation is expected to begin earlier in the morning with a higher likelihood of freezing rain.

By early afternoon, precipitation should become more widespread, particularly in Central and Eastern Ontario, as drier areas fill in with moisture. Despite this, snowfall rates are expected to remain manageable, likely staying under 1 cm per hour. However, snow could persist for a solid 6 to 8 hours through the late morning and afternoon, leading to gradual accumulation.

Meanwhile, the freezing rain threat will begin expanding toward Hamilton and the western GTA, with ice pellets potentially mixing in as the transition from snow to freezing rain occurs.

Gradually, precipitation will taper off in Deep Southwestern Ontario, with lingering drizzle as temperatures slowly rise above freezing. This slight warm-up will help melt any ice accretion from earlier in the day.

Across the rest of Southern Ontario, precipitation should wind down by late afternoon or early evening. In the wake of the system, some minor lake-effect snow may develop around Georgian Bay and Lake Huron, but we are not expecting any organized lake-effect activity at this time.

While Thursday’s system may be relatively minor, it could serve as a precursor to a much more impactful storm set to arrive this weekend.

Uncertainties remain, and details could shift as we get closer to Saturday. However, all major weather models continue to signal a strong system targeting Southern Ontario late Saturday into Sunday.

The exact track and intensity will determine which areas see the most significant impacts. At this point, current projections suggest a prolonged freezing rain threat for Deep Southwestern Ontario and areas along the Lake Erie shoreline. Meanwhile, heavy snow, with potential accumulations between 10 and 25 cm, could affect parts of the Golden Horseshoe, Central Ontario, and Eastern Ontario.

Again, this forecast is subject to change, but this storm has the potential to be a high-impact event for much of Southern Ontario. Stay tuned, as we’ll be providing more detailed updates in the coming days!