Groundhog Day Storm: Behind the forecast

Satellite image of the massive storm. Courtesy: NASA

Chris Scott, meteorologist

Overall, this storm is on track and can’t ‘miss.’ However, there are some wrinkles that we’re watching and we want to bring you in on the details.

The storm has been receiving significant attention, and for good reason because of the huge tract of North America that will be impacted-- from Texas to Newfoundland. However, the details of the storm are different for every area. In parts of the Southern Plains and Midwest U.S., this is an exceptional storm. For locations in Eastern Canada, it’s an unrealistic stretch to call this exceptional or paralyzing...it’s a large and significant winter storm, but the type of storm that we do expect. It’s been a couple of years since the Greater Toronto Area has seen a widespread storm of this magnitude, so this storm is getting it’s fair share of attention.

Let’s look at the possible wrinkles for the GTA. It’s guaranteed the storm hits fast and hard, starting later Tuesday evening, and peaking in intensity overnight with the heaviest snow and strong winds. The worst of the storm will hit when most people are sleeping, between 3-6 am. In fact, during this time, there is the slight chance of lightning – so don’t be shocked if you hear a crack of thunder in the pre-dawn hours – that’s how intense the precipitation will be!However, it looks like the heaviest snow will end rather abruptly just after dawn...and often this ‘dry slot’ as we call it moves in a bit faster than expected. This doesn’t mean the storm will be over at 8 am, it’s just part of this particular storm’s rhythm so to speak. There’s even the slight chance there could be some freezing drizzle for a brief period of time before some steadier snow builds back in during the late morning and early afternoon. Freezing drizzle isn’t in our official forecast because the chance is pretty small, but these are the kind of details that make forecasting so tricky.

Snowfall totals expected through Wednesday

Snowfall amounts can vary dramatically with a storm this large and intense. In Toronto, at least 15 cm of snow is likely, but there is a chance amounts could go up to 30 cm. While this seems like a huge range, winter storms do have very fine details that cause variations in snowfall. Regardless of the exact amount for your street, the bottom line is that it’s a significant shot of snow that will take some time to clear from roads and sidewalks. Coupled with a strong wind, especially very early Wednesday morning, this snow will make getting around rather tough.

It’s also a guarantee that the precipitation from this storm will end Wednesday evening, and Thursday will be a relatively quiet day in Toronto weather-wise. So, just focusing on the GTA, you can see how the picture is pretty clear that there is a storm that will hit hard overnight Tuesday into early Wednesday morning, and then linger with varying intensities of precipitation through Wednesday afternoon before ending Wednesday evening.

But the details will be what determines the exact amount of snow, and the impact on your day. Bottom line, if you love wild weather and you live in the Toronto-Hamilton area, either stay up really late Tuesday night, or get up very early Wednesday...otherwise, you may be a bit disappointed.

For the rest of us (okay, I’m actually part of the former ‘wild weather loving’ group), these details don’t change the fact that it is a good day to stay/work at home if possible, or if you have flexible hours, wait until the heaviest dump of snow has been cleared from the roads before venturing out.

Whatever you’re doing on Wednesday, from Windsor, Ontario to Windsor, Nova Scotia, stay safe and check out The Weather Network on TV to see how all the details play out for your area.