Our forecasting team is tracking an overachieving Clipper system tracking through the Lower Great Lakes Overnight. Dissipating West to East through Sunday AM.
A quick burst of snow begins near midnight tonight, persisting through the pre-dawn hours (5-6am) Sunday morning. Generally, 3-8cm is expected. Due to the nature of clipper systems amounts will vary throughout the forecast area.
Wind gusts to 60-70km/h are expected along the north shore of Lake Erie (along the Niagara Peninsula), early Sunday morning. Watch for local blowing snow and poor travel in the area.
Exercise caution if you are travelling early Sunday morning. Since it is a weekend, little impact to transportation is anticipated.
Alberta Clippers are synonymous for bringing snowfall lee of the Canadian Rockies, during December and January. These typically moisture-starved systems are fast movers, ejecting quickly out of Alberta, through the Southern Prairies – towards the Great Lakes. Read more about Alberta Clippers here.
A clipper is expected to form in Northern Alberta Saturday evening. Normally, these systems are more of a nuisance, accompanied by low snowfall totals and quick forward motion. On the contrary, this weekends system will flourish. Thanks to clashing temperatures and abundant Pacific moisture.
Accumulations will vary greatly throughout the Prairies, bearing in mind the heaviest snow will fall along a narrow swath. Current guidance suggests close to 15cm across the northern extent of the darker shaded region (in our forecast map). Including, Northern & Central Alberta. The heaviest snow (~20cm) will fall across Extreme Southwest Manitoba and Southeast Saskatchewan. *Model guidance has increased snowfall totals further into Southwestern Manitoba, where Environment Canada has issued snowfall warnings. Several warnings now stretch across parts of Prairies.
There will be another swath of snow tracking down the Rockies, bringing 10-20cm. It looks like Calgary will be limited to less than 5cm through Friday. By Saturday, a steep contrast in temperature envelopes the Prairies. Calgary will see a high of 9c and sunshine. Whereas, Eastern Saskatchewan will still be below freezing.
STRONG WINDS & BLOWING SNOW
Winds pickup between the Grande Prairie – Whitecourt corridor early Saturday evening. Winds sustained at or over 30km/h, gusting 60-80km/h. Gusty winds will overspread much of Alberta and Southern Saskatchewan overnight Saturday into Sunday morning. The strongest wind gusts aren’t expected to coincide with the heaviest swath of snow. Still, freshly fallen snowfall, which is dry and light – will combine with gusty winds. Bringing local blowing and drifting snow. Stay tuned to weather advisories, or statements pertaining to any potential road closures.
Winter returns to the Great Lakes, after an extended lull in activity and cold air between December and early January. Find out where, and, how bad the ‘next one’ will be.
An area of low-pressure tracks through Illinois late this evening. Tracking through Michigan & Northeast Ontario by Wednesday afternoon & evening. Precipitation begins as snow across Central, Northeastern, and much of Southwestern Ontario Tuesday evening.
Freezing rain and ice pellets begin after 9pm across the Windsor – Sarnia corridor. Changing to rain, with little impact. Freezing rain spreads north of Lake Erie through the overnight. 3-6 hours of freezing rain is expected before changing over to rain.
Snowfall continues across much of Central, Southwestern, and Eastern Ontario overnight into Wednesday morning. A lull in snow develops across the 400 corridor near 7am. Lowering snowfall totals across Southern Simcoe county; risk of freezing drizzle.
South of the 401/402 changes over to all rain during the early morning. Freezing rain continues along the escarpment (West of Lake Ontario). A changeover to rain continues North & East throughout the afternoon, proceeded by brief freezing rain.
Snow continues North of Lake Simcoe and North of Ottawa through the afternoon. A extended period (5-8 hours) of freezing rain develops Wednesday afternoon in Montreal, after a period of snow. Conditions will be hazardous in the City.
A primarily snow event stretching from Bruce and Huron county’s through Georgian Bay. Also, putting parts of Eastern and Northeastern Ontario in a swath of 15-25cm. Little accumulation north of Lake Erie, but watch for icing with the potential of 5-8mm of accretion before the changeover to rain. 2-4cm of snow across the GTA, with brief freezing rain. A larger swath of 5-10cm of snow is expected across the light blue shaded area on our forecast map.
A classic fall windstorm will track through the Great Lakes Tuesday, bringing strong winds, snow, and rain across Ontario.
A compact area of low-pressure is forecast to deepen overnight Monday, as it tracks through Michigan. Bringing strong wind & rain across Southern Ontario. Concurrently, bringing snow to Northwestern Ontario.
SOUTHERN ONTARIO: STRONG WINDS & RAIN SHOWERS
By Tuesday morning, rain showers will become more numerous as a large area of precipitation moves north from the United States. 5-15mm of rainfall in the morning, preceded by sunny breaks across South Central & Southwestern Ontario by the early/mid afternoon. Temperatures will likely spike into the low teens by the afternoon.
Winds will become stronger throughout the late morning. Becoming the strongest through the afternoon and evening. Widespread wind gusts between 60-80km/h is expected through the afternoon/evening Tuesday. The strongest winds, potentially exceeding 90km/h, are possible in the Niagara Region, Prince Edward, Bruce & Grey Counties.
The strong winds will likely strip many of the remaining leaves from trees. Remember to clean fallen leaves from storm drains.
While the South contends with wind & rain, Northwestern Ontario will see snowfall. The heaviest snowfall is expected across far-Northwestern Ontario. Another area of snowfall is expected northwest of Thunder Bay. General amounts between 5-10cms is expected Tuesday.
Much colder air with light-snow, is expected for Thunder Bay through Wednesday & Thursday.
COLDEST AIR OF THE SEASON IS ON THE HORIZON
The warm up will be short-lived. The coldest air of the season, accompanied by lake effect snow arrives this weekend. Daily low temperatures will become consistently negative beyond Friday, November 9th across Southern Ontario. With daytime highs around the freezing mark for several days. Lake effect snow will really begin to ramp up beginning late week.
A system developing in the Southeastern United States will track up the Eastern Seaboard this weekend, becoming a weather story across Eastern Canada.
A developing coastal system will bring a wintery mix across Southern Ontario, Quebec, and Northern New Brunswick.
A boundary will form in Southern Ontario between a cold & dry high-pressure system, and moist air arriving from the Southeast. Colder air will overspread Southern Ontario and Southern Quebec Saturday, owing to a cold Northeasterly wind. Concurrently, a large area of precipitation will push north into Southern Quebec and Southern Ontario.
Snow, mixing, rain and freezing rain is expected from Saturday morning to Sunday evening. Flurries will continue through Monday.
Across, Nova Scotia, PEI and much of New Brunswick will see primarily rain. Although, Northern New Brunswick could remain as a mix or snow depending on the track of the developing system.
Many residents East of Highway 6 and across the GTA have started the day with moderate wet snow.
A cold northeasterly wind will reinforce colder air by Saturday evening. Mixing or rain-showers will transition into a wintery mix of wet snow & ice pellets east of Highway 6, along/north of highway 407/7. Continuing through much of Central and Eastern Ontario (away from the lake shore). A few wet centimetres is possible. Especially for municipalities at higher elevation South and East of Georgian Bay. Please plan accordingly, as conditions will deteriorate through the day Saturday.
MARITIMES: Strong Winds & Heavy Rainfall
This system will be a rain and wind story across much of the Maritimes. The strongest winds, with gusts between 80-90km/h, will be located across the Bay of Fundy. Elsewhere winds across much of Nova Scotia, PEI and New Brunswick are expected to be gusting between 50-70km/h Sunday morning. Total rainfall amounts between 20-50mm is expected by Sunday afternoon. The heaviest rain falling in Southern New Brunswick and coastal Nova Scotia. Across Northern New Brunswick, a period of snow and mixing may persist into the overnight.
Flurries will begin north of the St. Lawrence Saturday evening. Montreal, and the Eastern Townships will likely changeover to rain late Saturday evening/overnight, with the arrival of warmer air.
For regions north of the St. Lawrence, this will be a snow and ice story. Stay tuned to further forecasts Saturday night through Sunday morning, this region could see a 5-8 hour window for freezing rain.
A frosty Saturday night ahead across much of Southern Ontario. Pleasant conditions Sunday, give way to a pair of clipper systems to start the work week.
It will be a cool and frosty Sunday morning across Southern Ontario. Sunny conditions, and light southwesterly winds, will allow temperatures to rebound in the afternoon. The first of two clipper systems brings rain showers (beginning) Monday morning. Dreary and cool conditions continue through the afternoon.
First Shot of Lake Effect Snow?
A clipper system will track through the Great Lakes late Tuesday through Wednesday. The passage of the low will be followed by a reinforcing shot of cold and dry air. Lake effect rainfall may bring graupel or hail to some locales in Central Ontario (Tuesday evening into Wednesday morning). Owing to, instability, and seasonably cold air building aloft.
Lake effect rainfall bands will transition to wet snowfall Wednesday night, Southeast of Lake Huron, and Georgian Bay.
Seasonably cool air 1.5km above the surface, will support lake effect snow. Abundant dry air, warm ground temperatures, and a building area of high pressure, should mitigate any risk of significant accumulation. We will monitor the risk over the coming days.
Colder air is beginning it’s decent across Southern & Central Ontario. Gusty winds this evening gives-way to Lake Effect rainfall Thursday night through Friday. First ‘bout of the season serves as a reminder that winter is coming.
Inland sections surrounding Agawa Bay to Montreal River Harbour will see Lake Effect rainfall beginning this evening. A transition to mixing or large flakes of wet snow is anticipated during the early morning hours Friday. Location: East of Lake Superior.
Accumulating snow will develop in Lake Effect bands near Wawa Friday night through Saturday.
Lake effect rainbands will setup tonight southwest of Georgian Bay and East of Lake huron. Owen Sound to Barrie to Orillia will be in for a chilly wet reminder that winter is coming. With rainfall bands meandering through the area.
Fairweather waterspouts are possible late Friday over Lakes Erie and Ontario, given the cold air aloft.
The winter possesses a unique set of challenges for drivers. Snow, rain and ice often coalesce into a challenging drive for commuters. Vehicle tires undergo tremendous stress during changing weather conditions. During periods of extreme temperature fluctuations (up or down), tire pressure can fluctuate enough to signal-on the tire pressure light in newer vehicles. Additionally, incorrect tire pressure can lower fuel economy, make a vehicle more susceptible to damage from potholes, impact vehicle handling, and cause tires to wear quickly and/or unevenly.
ALTERNATING TIRE PRESSURE
Changing weather conditions attributes to the measurement of pressure in your tires. Hot weather or a long road trip will increase tire pressure. However, very cold weather can cause your tire pressure to deviate from the recommended inflation pressure, activating the TPMS (Tire Pressure Monitoring System)* in newer vehicles. Most TPMS monitor under-inflation as it poses a greater risk while driving. Tires will wear unevenly on the inner or outer most edges of the tire. An under-inflated tire is not only noisier, it creates more frictional heat, and, therefore, more prone to blowouts. Furthermore, an under-inflated tire can cause costly damage to your vehicle during the pot-hole season. The tire will have difficulty absorbing the impact from potholes which can cause damage to rims, or worse.
Tire pressure changes while sitting overnight or during a long commute to work. Pressure can change by up to 5-psi from a 20-30 minute drive vs when parked overnight. Additionally, if the outside air temperature decreases by 5.5 degrees Celsius, the tire pressure will fall 1-psi. Conversely, if the air temperature increases 5.5 degrees Celsius, the tire pressure will rise by 1-psi.
It is recommended to check tire pressure at least once a month for all tires on your vehicle. It is important to note that you should only add or release air from your tires, after your vehicle has been sitting for several hours.
*Many newer vehicles (beyond 2008) have a tire pressure sensor that constantly measures the inflation of each tire.
TIRE PRESSURE & FUEL ECONOMY
Generally, the acceptable tire pressure range is between 30-35 PSI. Automotive manufacturers have different pressure specifications, designed to provide the maximum performance based on the vehicle. Refer to the gas tank cover or drivers-side door panel to find a vehicles recommended tire pressure. On the side-wall of a vehicle tire, the maximum allowed pressure is shown. It’s important to note this number is the maximum pressure the tire can operate at during full load. This number is not the pressure rating your tire should be inflated to.
Fuel economy will be impacted by improper tire inflation. The U.S. Department of Energy says that for every 1-psi drop in pressure, you can expect your gas mileage to lower by 0.4 percent. Inflating a tire beyond what is recommended from the vehicle manufacturer can improve fuel economy. Doing so can sacrifice handling and comfort; the vehicle will ride harshly over imperfections in the road. Additionally, the center thread of tire will wear quicker.
TIP: before towing a trailer, or a load of people add a couple PSI to the back wheels. Refer to your vehicle to see the recommended “at load” pressure.
CHECKING TIRE PRESSURE
Pick-up a standard or digital tire pressure gauge. In the morning, or before a long drive remove the cap from valve stem. Measure the PSI of pressure by firmly pushing the gauge to the vale stem. Ensure there is no air leak between the nipple and gauge to collect an accurate reading.
An area of low pressure will strengthen as it tracks through the Upper Midwestern United States. Bringing accumulating snow and gusty winds across Northwestern Ontario. Summer-like heat & humdity returns to Southern Ontario.
TIMING & ACCUMULATIONS
Snow flurries will begin mixing in along Highway 17 late Wednesday evening. With wet snow falling by Thursday morning. By Thursday afternoon, anywhere along and south of Highway 11 will likely be seeing rain.
North of Lake Superior, precipitation will fall as a cold rain with gusty winds. Including the Thunder Bay area, where cold rain and gusty winds will lead to a miserable day.
By Wednesday afternoon or late evening, cold air will wrap around the deepening system. Heavy snowfall will begin accumulating in a line from Kenora to Dryden to Sioux Lookout to Pickle Lake. Continuing into extreme Southeastern Manitoba. Moderate to heavy snowfall and gusty winds will persist, increasing in coverage across Northwestern Ontario through the day Thursday.
Projected amounts are subject to change based on the track & timing of the low + Hurricane Michael. Current guidance suggests a large swath of 20-30cm. 30-40cm could fall locally.
Actual accumulations will be largely dependant upon key factors: track of the low, temperature, and snowfall ratios. Moisture won’t be an issue with tropical moisture from Hurricane Michael.
While Northwestern Ontario deals with heavy snow, Northeastern Ontario will be dealing with heavy rainfall. A large swath of 50-75mm is expected East of Lake Superior.
THE TALE OF TWO SEASONS
As Northern Ontario deals with heavy rain and snow, Southern Ontario will get one last blast of summer. Temperatures Wednesday will likely be soaring into the mid or high-20s. With abundant humidity making it feel into the 30s. Forecast temperature & humidity readings will challenge all-time October records Tuesday and Wednesday.