Evening and Overnight Risk for Severe Thunderstorms (Friday, May 20th, 2022)

/

NOTE: You can click on the map to open a zoomable image which might be easier to read due to the small labels. If you prefer our old city label format, we have included that further down this article.

As previously mentioned, this forecast has been quite challenging. When there is an environment this strong (moisture + heat + wind shear) but a general lack of expected storms, it’s always a big question mark regarding if storms could potentially pop-up earlier than expected. Nevertheless, we’ve been over so many models and observations and we feel that our map, with a slight modification from yesterday’s preliminary forecast, which now extends the severe risk further into northeastern Ontario, should cover all the possibilities.

Several models are continuing to suggest the storms will arrive late and not be as significant. However, a few others suggest the storms roll into the Bruce Peninsula and the northern side of Lake Huron into areas around Sauble Beach around 7-8pm. If the storms arrive early, they’re going to likely be quite severe and could cause significant damaging wind gusts, large hail, isolated flooding, intense lightning, and perhaps even a tornado or two are possible. If the storms arrive around later into the evening, they won’t have as much of an opportunity to take advantage of the significant supercell environment that is already strengthening across much of southern, central and northeastern Ontario. However, severe storms are still possible overnight as they track into Muskoka and northeastern Ontario.

So far, areas like the Bruce Peninsula, the north side of Lake Huron, through the Georgian Bay regions and into parts of Muskoka and northeastern Ontario seem to be where the strongest nocturnal storms should arrive. 

The later they arrive, the less chance they have of producing significant severe weather.

We continue to hope that they arrive as late as possible and the outcome is simply a noisy/windy/rainy evening for some. *Fingers continued to be crossed* 🤞

There will also be the chance for thunderstorms on Saturday morning, potentially around the Hamilton area and there is some potential they could be severe.

More details ASAP!

Ice Day (Bus Cancellation) Outlook for Wednesday, March 30, 2022

/

NOTE: You can click on the map to open a zoomable image which might be easier to read due to the small labels. If you prefer our old city label format, we have included that further down this article.

Scattered freezing rain is expected to affect Southern Ontario starting Wednesday morning and continuing throughout the day. There is a chance of school bus cancellations, however, the lack of freezing rain warnings at the moment and the timing makes it less certain exactly where these cancellations will occur. We have given a widespread 50% chance for Southwestern Ontario including Windsor, Sarnia, Rural London, Huron/Perth and Grey/Bruce. Freezing rain will begin sometime around the mid-morning hours so we’re not confident enough that the conditions will be bad enough at 5-6 am when the decision is made.

If school boards consider the forecast for freezing rain to linger into the afternoon, they should cancel school buses in the morning, but this is very subjective depending on the board. If Environment Canada upgrades some regions to a freezing rain warning by morning then that would greatly increase the chance of an ice day. So keep in mind this forecast is based on the assumption that only special weather statements are in effect by morning. It could go either way depending on the local road conditions and the weather alerts in effect when the decision is made. We may see very few cancellations or widespread cancellations on Wednesday morning as it’s right on the line.

The probability of school bus cancellations is lower in the more urban school boards including London, Hamilton/Niagara and the GTA with the chance of an ice day ranging from 5-25%. Central and Eastern Ontario will see the freezing rain start late in the afternoon so it shouldn’t affect buses there, but we can’t rule it out as some of those school boards tend to be more proactive. A freezing rain warning is currently in effect for the Sudbury and North Bay region and the school boards there tend to be more sensitive to the weather so cancellations there are very likely (75%).

If there are any cancellations tomorrow morning, you can be sure we’ll be up bright and early beginning at 6 AM with our bus cancellations live blog to keep you updated.

FORECAST MAP WITH CITY LABELS

Disclaimer: Instant Weather has zero authority when it comes to bus and school closures. It is completely up to the school boards, bus companies, and local authorities as well as being up to parents to decide what is best for their children. This is simply our best guess based on our forecast. Also note that due to the current pandemic, some school boards have changed their policies on school bus cancellations. Some will continue the school day in a virtual format should there be school bus cancellations - check with your local board for more details.

Winter’s Grip on Ontario Continues With Freezing Rain Risk in the South and Heavy Snow in the North Between Wednesday and Thursday

/

It might be officially spring, but it appears that Mother Nature missed the memo as we are expecting a system to bring a messy mix of wintery precipitation across Ontario over the next few days. The effects of this storm will begin to be felt in Deep Southwestern Ontario during the predawn hours on Wednesday. This includes Windsor, Chatham, Sarnia and London where temperatures will be hovering near the freezing mark throughout the morning. As a result, there is the risk of freezing rain for several hours as the precipitation works its way throughout the region. Do note that this will be very temperature dependent and some areas may see just all rain if it’s slightly warmer than expected.

Later in the morning on Wednesday, we will see the precipitation push to the northeast into the rest of Southwestern Ontario and the GTA with the risk of freezing drizzle or rain. Again, this will be very dependent on the temperature so the worst conditions will be found in the higher elevations (K/W, Guelph and Orangeville etc.) with less of an impact closer to the lakeshore. This could lead to some icy driving conditions during the morning commute on Wednesday so be sure to leave plenty of time to get to your destination.

In terms of ice accretion, the heavier precipitation will be found throughout Deep Southwestern Ontario southeast of Lake Huron so they could pick up around 2-4mm of ice accretion. The rest of Southwestern Ontario and the GTA is expected to experience more scattered freezing rain so it won’t be as sustained with less than 2mm of total icing. We will see the freezing rain risk linger into the afternoon as temperatures still remain slightly below the freezing mark, but there will be a break in the precipitation which should help limit the impact. Temptarues will slowly rise above the freezing mark towards the evening and overnight into Thursday.

Another area of concern we’re closely watching is east of Georgian Bay and up into Northeastern Ontario. This area has the risk of freezing rain starting late Wednesday afternoon continuing into the overnight and Thursday morning. Those in Central and Eastern Ontario can expect between 2-6mm of ice accretion by Thursday morning as temperatures climb above the freezing mark overnight. The more prolonged freezing rain will be found north of Georgian Bay including Elliot Lake, Sudbury and North Bay. Several hours of heavy freezing rain with up to 6-10mm of ice accretion is possible. This amount of icing will likely lead to some power outages and impact to travel so consider avoiding any non-essential travel through the region.

Conditions on Thursday will do a complete 180 across Southern Ontario as warmer air push temperatures into the double digits during the morning and afternoon. This will be accompanied by scattered showers and rain with even the risk of an isolated non-severe thunderstorm. Strong to damaging wind gusts will also be an issue early Thursday morning and into the afternoon. Current indications suggest that regions east of Lake Huron into the GTA could see wind gusts ranging between 70-90km/h with locally stronger gusts up to 100km/h along the shorelines. More details on this will be covered in a separate wind forecast to be issued on Wednesday as we get closer to Thursday.

For Northern Ontario, the story will be more of a traditional snowstorm for a wide swath of the area. Along with the aforementioned prolonged freezing rain just north of Georgian Bay. Snow has already begun to move into Northwestern Ontario this evening around the Manitoba border. It is expected to spread eastward throughout the overnight and into Wednesday. The heaviest snow will be found from Thunder Bay through Geraldton and Moosonee starting Wednesday afternoon and evening. Conditions here will be quite poor with blowing snow and rapid accumulation - road and highway closures are likely later in the day on Wednesday. There will be a short break for the snow early Thursday morning, but another round of heavy snow is expected to move through Northeastern Ontario (it should remain east of Thunder Bay closer to Wawa and Timmins) during the day on Thursday.

Total snowfall accumulation in the hardest-hit regions will likely exceed 20cm and could even approach 30cm by the end of Thursday. This includes Geraldton, Kapuskasing, Wawa and Cochrane while Thunder Bay will likely top out at around 15cm. Lower snowfall accumulation of around 5-15cm is expected through Chapleau and Timmins where sleet and freezing rain mixing in will reduce accumulation. Sault Ste. Marie, Elliot Lake, Sudbury and Temiskaming Shores will experience mainly freezing rain with significant icing of 6mm+ possible. The freezing rain will transition over to regular rain Thursday morning as the temperature climbs above the freezing mark.

Temporary Return to Winter As Snow Squalls Could Dump Up to 30cm of Snow Through Parts of Southern Ontario’s Snowbelt by Monday

/

We might have been treated to quite a mild start to spring across Southern Ontario so far, but that is about to change over the next few days. Cold arctic air will flood into the region late Saturday night into Sunday morning bringing temperatures that feel more like early December than the beginning of spring. It will only get colder as we head into Monday with wind chills approaching the -20s in some parts of Southern Ontario as you start the day on Monday!

This colder area will also help turn back on the lake effect snow machine over the next few days with snow squalls potentially bringing significant snowfall accumulation to parts of the Snowbelt. Poor driving conditions with blowing snow and rapid snowfall accumulation will be a common occurrence starting early Sunday morning lasting throughout the day and into early Monday. Localized road and highway closures are likely in the affected region, so it’s a good idea to avoid travelling east of Lake Huron and south of Georgian Bay until later on Monday.

Light scattered flurries are currently ongoing in parts of Southwestern and Central Ontario as of Saturday afternoon as temperatures slowly make their way below the freezing mark. By midnight, we should see some more persistent and heavy bands of snow develop around the eastern Lake Huron shoreline and south of Georgian Bay. It doesn’t appear that this area of lake effect snow will be particularly organized until we get into mid to late morning on Sunday as a more intense squall will set up. The main squall will be located off Lake Huron somewhere between Kincardine and Goderich along with a secondary squall off Georgian Bay coming inland over Meaford and extending into the Collingwood/Wasaga Beach area.

There is some disagreement among the models on the exact wind direction which makes it difficult to narrow down the placement of the squalls. However, it does appear that the squall off Lake Huron will meander around a bit throughout the day on Sunday which should help limit the overall accumulation for each location. It looks like it will start out near Goderich, Grand Bend and Exeter early Sunday morning before shifting northward towards Kincardine and Hanover by the afternoon. It should slowly make its way back to the south and could lock in for a few hours around Exeter and Stratford into early Monday morning.

For Georgian Bay, current indications suggest that the lake effect snow will be mostly contained to the shoreline with a focus on the Collingwood, Meaford and Wasaga Beach region. By Sunday evening, the snow squall may strengthen to an extent and reach further inland towards Barrie, Innisfil and across Hwy 400 into York Region. This will bring the chance for a quick 5-10cm of snow in this area with locally even higher amounts if it locks in for several hours. Parts of the GTA and the City of Toronto may even see some heavier snow around midnight as the edge of the squall shifts into the city, but accumulation isn’t expected to be significant.

The snow squall activity will taper off by late Monday morning or early afternoon. Depending on the strength of the squalls in the morning, it could prompt some school bus cancellations around Lake Huron and Georgian Bay on Monday. In terms of overall snowfall accumulation including tonight, Sunday and early Monday, we expect that some areas east of Lake Huron could pick up to 30cm of snow. This includes Goderich, Kincardine, Wingham, Listowel and Hanover. However, not everyone will see anywhere near 30cm as snow squalls are very localized and the exact totals for each location will vary significantly from a few centimetres to near 30cm. It all depends on the wind direction and intensity of the squall, but the potential is there.

Surrounding regions including Grand Bend and Stratford along with the Southern Georgian Bay shoreline can expect up to 20cm by Monday from the snow squall activity. Those in London, K/W, Owen Sound and Barrie could see the occasional brief snow squall move through the area leading to accumulation up to 10cm. Do note that there is some higher uncertainty around the Barrie area and southward along Hwy 400 where one model does show that the squall could become quite intense overnight Sunday. It’s not out of the question that localized accumulation here approaches 15-20cm, but there isn’t enough confidence to include it on the map. In addition to this, the Niagara region mainly through Fort Erie could see a brief squall early Sunday morning off Lake Erie before it moves stateside leading to up to 10cm of snow.

Ice Day (Bus Cancellation) Outlook for Wednesday, March 23, 2022

/

NOTE: You can click on the map to open a zoomable image which might be easier to read due to the small labels. If you prefer our old city label format, we have included that further down this article.

A risk of prolonged freezing rain starting Wednesday morning will likely result in many school bus cancellations mainly throughout the Dundalk Highlands and into Central Ontario. Environment Canada has a Freezing Rain Warning in effect for the higher elevations northwest of the GTA including Kitchener, Guelph and Orangeville warning of ‘significant freezing rain’ which will almost certainly lead to the school boards in those regions to cancel school buses and perhaps even close schools. As a result, we have given that area a 75-90% chance of an ‘ice day’ for Wednesday. The only exception is the London and Hamilton region which are more urban and it’s questionable if the severity of this event will merit cancellations in those regions.

Outside of this region, Environment Canada does have a Special Weather Statement in effect for much of Central Ontario mentioning the risk of freezing rain. How this is interpreted will depend on each board so we have given some regions a 50% chance indicating that it could go either way. While the boards that tend to be less sensitive to weather have a 25% chance of seeing cancellations. Those in the Parry Sound/North Bay region have a 75% chance mainly because that school board tends to cancel whenever there is wintery weather in the forecast during the school day.

We don’t expect the cancellations to extend into the urban school board around the GTA as this freezing rain event will be mainly contained to the higher elevations. However, it can’t be ruled out depending on the exact temperature in the morning so we’ve still given them a 10-25% chance of seeing an ice day.

If there are any cancellations tomorrow morning, you can be sure we’ll be up bright and early beginning at 6 AM with our bus cancellations live blog to keep you updated.

FORECAST MAP WITH CITY LABELS

Disclaimer: Instant Weather has zero authority when it comes to bus and school closures. It is completely up to the school boards, bus companies, and local authorities as well as being up to parents to decide what is best for their children. This is simply our best guess based on our forecast. Also note that due to the current pandemic, some school boards have changed their policies on school bus cancellations. Some will continue the school day in a virtual format should there be school bus cancellations - check with your local board for more details.

Freezing Rain Risk and Damaging Wind Gusts Possible Across Southern Ontario on Wednesday

/

A moisture-laden Texas low is expected to bring a messy mix of precipitation to Southern Ontario throughout the day on Wednesday. The main concern will be the risk of prolonged freezing rain in the higher elevations northwest of the GTA along with parts of Central Ontario during the morning on Wednesday. Combined with strong wind gusts reaching 80-100km/h, particularly through Southwestern Ontario will likely result in some localized power outages in the affected regions. For the rest of Southern Ontario, we are looking at heavy rainfall with generally between 15-30mm of rain accumulation although some parts of Deep Southwestern Ontario including Windsor could approach 40-50mm thanks to some thunderstorm activity later in the day on Wednesday. This may result in some localized flooding so be on alert for that if you live in a flood-prone area.

Precipitation associated with this system will begin to reach our region just after midnight starting as rain for Deep Southwestern Ontario. However, by the mid-morning hour, the precipitation will clash with below-freezing temperatures hovering around -2 to 0°C around the Orangeville and K/W area. This will allow for the development of a band of freezing rain that is expected to last for several hours. Those in the surrounding regions including London, Woodstock, Hamilton and the GTA away from the lakeshore could see some brief freezing rain or ice pellets before temperatures quickly rise above the freezing mark. Another stubborn pocket of cold air over Central Ontario including Algonquin Park and Bancroft will create the environment for some freezing rain here late Wednesday more and into the afternoon.

There is some disagreement among the models on exactly how fast the temperatures will warm up later in the day. One model, in particular, is quite aggressive showing below-freezing temperatures over the Dundalk Highlands lingering into the evening. As a result, that would lead to a fairly heavy icing event of up to 8-12mm of ice accretion possible for the K/W, Orangeville and Guelph region. Although other models show a faster warm-up with the freezing rain risk ending by the mid-afternoon which would limit accretion to 2-4mm max. We’re leaning more towards the 2-4mm outcome as it seems to have more agreement, but do keep in mind that locally up to 8mm can’t be ruled out if the cold air holds on for a few more hours. All freezing rain will come to an end by the end of the day Wednesday as warmer air push into the region. This will also help melt any ice accretion and lessen the impact on the power grid.

As mentioned above, this system will also feature very strong wind gusts mainly during the morning on Wednesday. The strongest wind gusts will be found along the Lake Huron shoreline with the maximum wind gust approaching 90-110km/h in this region. Other parts of Southwestern Ontario can expect gusts around 85-95km/h and 80-90km/h around Lake Simcoe into the GTA. Wind gusts will remain quite strong throughout the day on Wednesday but should begin to taper off as we head into the evening. Aside from the potential wind damage, this will also present an issue when combined with the freezing rain during the morning on Wednesday. Power outages can’t be ruled out in those regions that see both the strong winds and freezing rain.

We are also closely watching the risk of thunderstorms in Deep Southwestern Ontario for Wednesday afternoon and evening. Current data appears to keep the strongest ingredients south of the border so the severe risk should be very low, but the chance is still there that we see an isolated marginally severe storm sneak across the border mainly in the Windsor-Essex region. The main threat would be some small to medium-sized hail and strong wind gusts.